Multimedia Programming Interface
and Data Specifications 1.0

Issued as a joint design by IBM Corporation and Microsoft Corporation
August 1991

This document describes the programming interfaces and data specifications for multimedia thatare common to both OS/2 and Windows environments. These specifications may be enhanced toincorporate new technologies or modified based on customer feedback and, as such, specifications
incorporated into any final product may vary.

Microsoft is a registered trademark, and Windows is a trademark of Microsoft Corp.
IBM and OS/2 are registered trademarks of International Business Machines Corporation.

Contents

Contents
Chapter 1 ....................................................................................................... Overview of Multi
Resource Interchange File Format...........................................................................................1-1
Multimedia File Formats.........................................................................................................1-1
Media Control Interface ..........................................................................................................1-2
Registering Multimedia Formats .............................................................................................1-2

Chapter 2 ....................................................................................................... Resource Intercha
About the RIFF Tagged File Format .......................................................................................2-1
Notation Conventions ......................................................................................................2-1
Chunks ............................................................................................................................2-2
RIFF Forms .....................................................................................................................2-3
Defining and Registering RIFF Forms..............................................................................2-3
Registered Form and Chunk Types ............................................................................2-4
Unregistered (Form-Specific) Chunk Types...............................................................2-4
Notation for Representing Sample RIFF Files .........................................................................2-5
Basic Notation for Representing RIFF Files......................................................................2-5
Escape Sequences for Four-Character Codes and String Chunks .......................................2-7
Extended Notation for Representing RIFF Form Definitions.............................................2-8
Atomic Labels .................................................................................................................2-10
A Sample RIFF Form Definition and RIFF Form .............................................................2-11
Storing Strings in RIFF Chunks ..............................................................................................2-12
NULL-Terminated String (ZSTR) Format .................................................................2-12
String Table Format ..................................................................................................2-13

NULL-Terminated, Byte Size Prefix String (BZSTR) Series......................................2-13
Multiline String Format.............................................................................................2-13
Choosing a Storage Method ......................................................................................2-13
LIST Chunk ...........................................................................................................................2-14
INFO List Chunk.............................................................................................................2-14
CSET (Character Set) Chunk ..................................................................................................2-16
Country Codes .................................................................................................................2-16
Language and Dialect Codes ............................................................................................2-17
JUNK (Filler) Chunk ..............................................................................................................2-18
Compound File Structure ........................................................................................................2-18
Structural Overview.........................................................................................................2-19
Compound File Table of Contents (CTOC) Chunk ...........................................................2-19
Structural Overview ..................................................................................................2-19
Header Information...................................................................................................2-21
Parameter Table Definition .......................................................................................2-21
Header Parameter Table ............................................................................................2-22
CTOC Table Entries..................................................................................................2-22
Usage Codes for Extra Header and Extra Entry Fields................................................2-24
Compression of Compound File Elements .................................................................2-26
Compound File Element Group (CGRP) Chunk ...............................................................2-27
Placement of the CTOC and CGRP Chunks .....................................................................2-27

Chapter 3 ....................................................................................................... Multimedia File Fo
Bundle File Format.................................................................................................................3-1
Device Independent Bitmap File Format .................................................................................3-1
Overview of DIB Structure ..............................................................................................3-2
Bitmap File Header..........................................................................................................3-2
Bitmap Information Header..............................................................................................3-3
Information Header Structures...................................................................................3-4

Bitmap Color Table .........................................................................................................3-6
Color Table Structure................................................................................................3-6
Order of Colors.........................................................................................................3-6
Field Descriptions .....................................................................................................3-6
Locating the Color Table...........................................................................................3-7
Interpreting the Color Table ......................................................................................3-7
Bitmap Data ....................................................................................................................3-8
Windows 3.0 Bitmap Compression Formats .....................................................................3-8
Compression of 8-Bit-Per-Pixel DIBs........................................................................3-8
Compression of 4-Bit-Per-Pixel DIBs........................................................................3-9
RIFF Device-Independent Bitmap File Format ........................................................................3-10
Simple RDIB Format .......................................................................................................3-10
Extended RDIB Format ...................................................................................................3-10
Bitmap Header Chunk...............................................................................................3-11
Transitional Compression..........................................................................................3-16
CCC Compression ....................................................................................................3-17
Palette Chunk ...........................................................................................................3-17
External Palette Chunk..............................................................................................3-17
Bitmap Data Chunk...................................................................................................3-17
MIDI and RIFF MIDI File Formats.........................................................................................3-18
Palette File Format .................................................................................................................3-18
Simple PAL Format .........................................................................................................3-18
Extended PAL Format .....................................................................................................3-19
Rich Text Format (RTF) .........................................................................................................3-22
Waveform Audio File Format (WAVE) ..................................................................................3-22
WAVE Format Chunk .....................................................................................................3-22
WAVE Format Categories ...............................................................................................3-23
Pulse Code Modulation (PCM) Format......................................................................3-24

Storage of WAVE Data....................................................................................................3-26
FACT Chunk...................................................................................................................3-26
Cue-Points Chunk............................................................................................................3-27
Examples of File Position Values ..............................................................................3-28
Playlist Chunk .................................................................................................................3-29
Associated Data Chunk....................................................................................................3-29
Label and Note Information ......................................................................................3-30
Text with Data Length Information ...........................................................................3-30
Embedded File Information.......................................................................................3-31

Chapter 4 ....................................................................................................... Media Control Int
MCI Command Strings...........................................................................................................4-1
Example of MCI Command Use.......................................................................................4-2
Categories of MCI Command Strings...............................................................................4-2
Command Syntax Conventions ........................................................................................4-3
System Commands ..........................................................................................................4-3
Required Commands........................................................................................................4-3
Basic Commands .............................................................................................................4-4
Extended Commands .......................................................................................................4-4
Extended Commands Reserved for Future Use ..........................................................4-4
Creating a Command String .............................................................................................4-5
About MCI Device Types ................................................................................................4-6
Using MCI Command Strings.................................................................................................4-6
Opening a Device ............................................................................................................4-6
Opening Simple Devices ...........................................................................................4-7
Opening Compound Devices .....................................................................................4-7
Using the Shareable Flag...........................................................................................4-8
Using the Alias Flag..................................................................................................4-8
Opening New Device Elements .................................................................................4-8

Closing a Device..............................................................................................................4-8
Shortcuts and Variations for MCI Commands...................................................................4-9
Using All as a Device Name......................................................................................4-9
Combining the Device Type and Device Element Name ............................................4-9
Automatic Open........................................................................................................4-9
Automatic Close .......................................................................................................4-9
Using Wait and Notify Flags............................................................................................4-10
Using the Notify Flag................................................................................................4-10
Obtaining Information From MCI Devices .......................................................................4-11
The Play Command .........................................................................................................4-11
Stop, Pause, and Resume Commands ...............................................................................4-11
MCI System Commands .........................................................................................................4-12
Required Commands for All Devices ......................................................................................4-13
Basic Commands for Specific Device Types ...........................................................................4-14
CD Audio (Redbook) Commands ...........................................................................................4-17
MIDI Sequencer Commands...................................................................................................4-20
Videodisc Player Commands ..................................................................................................4-25
Waveform Audio Commands..................................................................................................4-29

Chapter 1

Overview of Multimedia Specifications

This document describes the file format and control interface specifications for multimedia. These
specifications allow developers to use common file format and device control interfaces.

Resource Interchange File Format
The Resource Interchange File Format (RIFF), a tagged file structure, is a general specification
upon which many file formats can be defined. The main advantage of RIFF is its extensibility; fileformats based on RIFF can be future-proofed, as format changes can be ignored by existing
applications.
The RIFF file format is suitable for the following multimedia tasks:•

Playing back multimedia data•

Recording multimedia data•

Exchanging multimedia data between applications and across platforms

Chapter 2, “ Resource Interchange File Format,” describes the RIFF format.

Multimedia File Formats
A number of RIFF-based and non-RIFF file formats have been defined for the storage ofmultimedia data. Chapter 3, “ Multimedia File Formats,” describes the following file formats:•

Bundle File Format•

Device-Independent Bitmap (DIB) and RIFF DIB file formats•

Musical Instrument Digital Interface (MIDI) and RIFF MIDI file formats•

Palette File Format•

Rich Text File Format•

Waveform Audio File Format

Media Control Interface
The Media Control Interface (MCI) is a high-level control mechanism that provides a deviceindependent interface to multimedia devices and resource files.
The Media Control Interface (MCI) provides a command set for playing and recording multimedia
devices and resource files. Developers creating multimedia applications are encouraged to use thishigh-level command interface rather than the low-level functions specific to each platform. The
MCI command set acts as a platform-independent layer that sits between multimedia applications
and the underlying system software.
The MCI command set is extensible in two ways:•

Developers can incorporate new multimedia devices and file formats in the MCI command set
by creating new MCI drivers to interpret the commands.

•

New commands and command options can be added to support special features or functions
required by new multimedia devices or file formats.

Using MCI, an application can control multimedia devices using simple command strings like
open, play, and close. The MCI command strings provide a generic interface to different
multimedia devices, reducing the number of commands a developer needs to learn. A multimedia
application might even accept MCI commands from an end user and pass them unchanged to the
MCI driver, which parses the command and performs the appropriate action.
Chapter 3, “ Media Control Interface,” describes MCI and its command set in detail.

Registering Multimedia Formats
This document discusses several multimedia codes and formats that require registration. These
multimedia elements include the following:•

Compression techniques•

RIFF form types, chunk IDs, and list types•

Compound-file usage codes•

Waveform audio format codes

To register these multimedia elements, request a Multimedia Developer Registration Kit from thefollowing group:
Microsoft Corporation
Multimedia Systems Group
Product Marketing
One Microsoft Way
Redmond, WA 98052-6399
The Multimedia Developer Registration Kit also lists currently defined multimedia elements.

Chapter 2

Resource Interchange File Format

The Resource Interchange File Format (RIFF) is a tagged file structure developed for use on
multimedia platforms. This chapter defines RIFF and describes the file structures based on RIFF.
If your application requires a new file format, you should define it using the RIFF tagged filestructure described in this chapter.

About the RIFF Tagged File Format
RIFF (Resource Interchange File Format) is the tagged file structure developed for multimedia
resource files. The structure of a RIFF file is similar to the structure of an Electronic Arts IFF file.
RIFF is not actually a file format itself (since it does not represent a specific kind of information),
but its name contains the words “ interchange file format” in recognition of its roots in IFF. Referto the EA IFF definition document, EA IFF 85 Standard for Interchange Format Files, for a list ofreasons to use a tagged file format.
RIFF has a counterpart, RIFX, that is used to define RIFF file formats that use the Motorola
integer byte-ordering format rather than the Intel format. A RIFX file is the same as a RIFF file,
except that the first four bytes are ‘RIFX’ instead of ‘RIFF’, and integer byte ordering isrepresented in Motorola format.

Notation Conventions
The following table lists some of the notation conventions used in this document. Further
conventions and the notation for documenting RIFF forms are presented later in the document in
the section “ Notation for Representing Sample RIFF Files.”Notation

Description<element label>

RIFF file element with the label “ element label”<element label: TYPE>

RIFF file element with data type “ TYPE”[<element label>]

Optional RIFF file element<element label>...

One or more copies of the specified element[<element label>]...

Zero or more copies of the specified element

Chunks
The basic building block of a RIFF file is called a chunk. Using C syntax, a chunk can be defined
as follows:
typedef unsigned long DWORD;
typedef unsigned char BYTE;
typedef DWORD FOURCC;// Four-character code

typedef FOURCC CKID;
typedef DWORD CKSIZE;// Four-character-code chunk identifier// 32-bit unsigned size value

typedef struct {CKID
CKSIZE
BYTE} CK;// Chunk structure// Chunk type identifier// Chunk size field (size of ckData)// Chunk data

ckID;
ckSize;ckData[ckSize];

A FOURCC is represented as a sequence of one to four ASCII alphanumeric characters, paddedon the right with blank characters (ASCII character value 32) as required, with no embedded
blanks.
For example, the four-character code ‘FOO’ is stored as a sequence of four bytes: 'F', 'O', 'O', ' ' inascending addresses. For quick comparisons, a four-character code may also be treated as a 32-bit
number.
The three parts of the chunk are described in the following table:

Part

Description

ckID

A four-character code that identifies the representation of the chunk data
data. A program reading a RIFF file can skip over any chunk whose chunk
ID it doesn't recognize; it simply skips the number of bytes specified by
ckSize plus the pad byte, if present.

ckSizeA 32-bit unsigned value identifying the size of ckData. This size value does
not include the size of the ckID or ckSize fields or the pad byte at the end of
ckData.

ckDataBinary data of fixed or variable size. The start of ckData is word-alignedwith respect to the start of the RIFF file. If the chunk size is an odd number ofbytes, a pad byte with value zero is written after ckData. Word aligning
improves access speed (for chunks resident in memory) and maintains
compatibility with EA IFF. The ckSize value does not include the pad byte.

We can represent a chunk with the following notation (in this example, the ckSize and pad byte
are implicit):<ckID> ( <ckData> )Two types of chunks, the ‘LIST’ and ‘RIFF’ chunks, may contain nested chunks, or subchunks.
These special chunk types are discussed later in this document. All other chunk types store asingle element of binary data in <ckData>.

RIFF Forms
A RIFF form is a chunk with a ‘RIFF’ chunk ID. The term also refers to a file format that follows
the RIFF framework. The following is the current list of registered RIFF forms. Each is describedin Chapter 3, “ Multimedia File Formats.”

Form Type

Description

PAL

RIFF Palette Format

RDIB

RIFF Device Independent Bitmap Format

RMID

RIFF MIDI Format

RMMP

RIFF Multimedia Movie File Format

WAVE

Waveform Audio Format

Using the notation for representing a chunk, a RIFF form looks like the following:
RIFF ( <formType> <ck>... )The first four bytes of a RIFF form make up a chunk ID with values ‘R’, ‘I’, ‘F’, ‘F’. The ckSize
field is required, but for simplicity it is omitted from the notation.
The first DWORD of chunk data in the ‘RIFF’ chunk (shown above as <formType>) is a fourcharacter code value identifying the data representation, or form type, of the file. Following theform-type code is a series of subchunks. Which subchunks are present depends on the form type.
The definition of a particular RIFF form typically includes the following:•

A unique four-character code identifying the form type•A list of mandatory chunks•

A list of optional chunks•

Possibly, a required order for the chunks

Defining and Registering RIFF Forms
The form-type code for a RIFF form must be unique. To guarantee this uniqueness, you mustregister any new form types before release. See “ Registering Multimedia Formats” in Chapter 1,“ Overview of Multimedia Specifications,” for information on registering RIFF forms.
Like RIFF forms, RIFX forms must also be registered. Registering a RIFF form does not
automatically register the RIFX counterpart. No RIFX form types are currently defined.

Registered Form and Chunk Types
By convention, the form-type code for registered form types contains only digits and uppercase
letters. Form-type codes that are all uppercase denote a registered, unique form type. Uselowercase letters for temporary or prototype chunk types.
Certain chunk types are also globally unique and must also be registered before use. These
registered chunk types are not specific to a certain form type; they can be used in any form. If aregistered chunk type can be used to store your data, you should use the registered chunk type
rather than define your own chunk type containing the same type of information.
For example, a chunk with chunk ID ‘INAM’ always contains the name or title of a file. Also,
within all RIFF files, filenames or titles are contained within chunks with ID ‘INAM’ and have astandard data format.

Unregistered (Form-Specific) Chunk Types
Chunk types that are used only in a certain form type use a lowercase chunk ID. A lowercase
chunk ID has specific meaning only within the context of a specific form type. After a form
designer is allocated a registered form type, the designer can choose lowercase chunk types to use
within that form. See “ Registering Multimedia Formats” in Chapter 1, “ Overview of Multimedia
Specifications,” for information on registering form types.
For example, a chunk with ID ‘scln’ inside one form type might contain the “ number of scanlines.” Inside some other form type, a chunk with ID ‘scln’ might mean “ secondary lambda
number.”Notation for Representing Sample RIFF Files
RIFF is a binary format, but it is easier to comprehend an ASCII representation of a RIFF file.
This section defines a standard notation used to present samples of various types of RIFF files. If
you define a RIFF form, we urge you to use this notation in any file format samples you provide inyour documentation.

Basic Notation for Representing RIFF Files
The following table summarizes the elements of the RIFF notation required for representing
sample RIFF files:

Notation

Description<ckID> (<ckData>)
The chunk with ID <ckID> and data <ckData>. As previously
described, <ckID> is a four-character code which may be enclosed
by single quotes for emphasis.
For example, the following notation describes a ‘RIFF’ chunk with aform type of ‘QRST’. The data portion of this chunk contains a‘FOO’ subchunk.
RIFF('QRST' FOO(17 23))

The following example describes an ‘ICOP’ chunk containing thestring “ Copyright Encyclopedia International.” :'ICOP' ("Copyright Encyclopedia International."Z)<number>[<modifier>]
A number in Intel format, where <number> is an optional sign(+ or -) followed by one or more digits and modified by the optional<modifier>. Valid <modifier> values follow:
Modifier

MeaningNone16-bit number in decimal format

H16-bit number in hexadecimal format

C

8-bit number in decimal format

CH

8-bit number in hexadecimal format

L32-bit number in decimal format

LH

32-bit number in hexadecimal format

Several examples follow:
0
65535
-1
0L

4a3c89HL-1C
21HC

Note that -1 and 65535 represent the same value. The application
reading this file must know whether to interpret the number as
signed or unsigned.
'<chars>'
A four-character code (32-bit quantity) consisting of a sequence ofzero to four ASCII characters <chars> in the given order. If<chars> is less than four characters long, it is implicitly padded on
the right with blanks. Two single quotes is equivalent to four blanks.
Examples follow.
'RIFF''xyz'''<chars> can include escape sequences, which are combinations ofcharacters introduced by a backslash (\) and used to represent othercharacters. Escape sequences are listed in the following section.
"<string>"[<modifier>]

The sequence of ASCII characters contained in <string> andmodified by the optional modifier <modifier>. The quoted text can
include any of the escape sequences listed in the following section.
Valid <modifier> values follow:
Modifier

Meaning

none

No NULL terminator or size prefix.

Z

String is NULL-terminatedB

String has an 8-bit (byte) size prefix

W

String has a 16-bit (word) size prefix

BZ

String has a byte-size prefix and is NULL-terminated

WZ

String has a word-size prefix and is NULL-terminated

NULL-terminated means that the string is followed by a characterwith ASCII value 0. A size prefix is an unsigned integer, stored as abyte or a word in Intel format preceding the string characters, thatspecifies the length of the string. In the case of strings with BZ or
WZ modifiers, the size prefix specifies the size of the string without
the terminating NULL.
The various string formats referred to above are discussed in"Storing Strings in RIFF Chunks," following later in this section., +Examples follow:"No prefix, no NULL terminator""No prefix, NULL terminator"Z"Byte prefix, NULL terminator"BZ

Escape Sequences for Four-Character Codes and String Chunks
The following escape sequences can be used in four-character codes and string chunks:

Escape Sequence

ASCII Value

Description\n10

Newline character\t

9

Horizontal tab character\b

8

Backspace character\r

13

Carriage return character\f12

Form feed character\\

92

Backslash\'

39

Single quote\"

34

Double quote\ddd

Octal ddd

Arbitrary character

Extended Notation for Representing RIFF Form Definitions
To unambiguously define the structure of new RIFF forms, document the RIFF form using thebasic notation along with the following extended notation:

Notation

Description<name>
A label that refers to some element of the file, where <name> is the name of
the label. Examples follow:<NAME-ck><GOBL-form><bitmap-bits><foo>

Conventionally, a label that refers to a chunk is named <ckID-ck>, where‘ckID’ is the chunk ID. Similarly, a label that refers to a RIFF form is named<formType-form>, where “ formType” is the name of the form's type.
<name> ➝ elements
The actual data represented by <name> is defined as elements.
This states that <name> is an abbreviation for elements, where elements is asequence of other labels and literal data. An example follows:<GOBL-form> ➝ RIFF ( 'GOBL' <form-data> )This example defines label <GOBL-form> as representing a RIFF form withchunk ID ‘GOBL’ and data equal to <form-data>, where <form-data> is alabel that would be defined in another rule. Note that a label may represent
any data, not just a RIFF chunk or form.
Note: A number of atomic labels are defined in the section “ Atomic Labels”
later in this document. These labels refer to primitive data types.
<name:type>This is the same as <name>, but it also defines <name> to be equivalent to<type>. This notation obviates the following rule:<name> ➝ <type>This allows you to give a symbolic name to an element of a file format and to
specify the element data type. An example follows:<xyz-coordinate> ➝ <x:INT> <y:INT> <z:INT>

This defines <xyz-coordinate> to consist of three parts concatenated together:<x>, <y>, and <z>. The definition also specifies that <x>, <y>, and <z> areintegers. This notation is equivalent to the following:<xyz-coordinate> ➝ <x> <y> <z><x> ➝ <INT><y> ➝ <INT><z> ➝ <INT>[elements]

An optional sequence of labels and literal data. Surrounded by square
brackets, it may be considered an element itself. An example follows:<FOO-form> ➝ RIFF('FOO' [<header-ck>] <data-ck>)

This example defines form “ FOO” with an optional header chunk followed
by a mandatory data chunk.
el1 | el2 | ... | elN
Exactly one of the listed elements must be present. An example follows:<hdr-ck> ➝ hdr(<hdr-x> | <hdr-y> | <hdr-z>)

This example defines the ‘hdr’ chunk's data as containing one of <hdr-x>,<hdr-y>, or <hdr-z>.
element...
One or more occurrences of element may be present. An ellipsis has thismeaning only if it follows an element; in cases such as “ el1 | el2 | ... | elN,”the ellipsis has its ordinary English meaning. If there is any possibility ofconfusion, an ellipsis should only be used to indicate one or more
occurrences. An example follows:<data-ck> ➝ data(<count:INT> <item:INT>...)

This example defines the data of the ‘data’ chunk to contain an integer<count>, followed by one or more occurrences of the integer <item>.
[element]...
Zero or more occurrences of element may be present. An example follows.
<data-ck> ➝ data(<count:INT> [<item:INT>]...)

This example defines the data of the ‘data’ chunk to contain an integer<count> followed by zero or more occurrences of an integer <item>.
{elements}
The group of elements within the braces should be considered a single
element. An example follows:<blorg> ➝ <this> | {<that> | <other>}...

This example defines <blorg> to be either <this> or one or more occurrencesof <that> or <other>, intermixed in any way. Contrast this with the following
example:<blorg> ➝ <this> | <that> | <other>...

This example defines <blorg> to be either <this> or <that> or one or more
occurrences of <other>.

struct { ...} name
A structure defined using C syntax. This can be used instead of a sequence oflabels if a C header (include) file is available that defines the structure. The
label used to refer to the structure should be the same as the structure's
typedef name. An example follows:<3D_POINT> ➝ struct {INT x;
INT y;
INT z;} 3D_POINT// x-coordinate// y-coordinate// z-coordinate

Wherever possible, the types used in the structure should be the types listed in
the following section, “ Atomic Labels,” because these types are more
portable than C types such as int. The structure fields are assumed to bepresent in the file in the order given, with no padding or forced alignment.
Unless the RIFF chunk ID is ‘RIFX’, integer byte ordering is assumed to bein Intel format.
// comment
An explanatory comment to a rule. An example follows:<weekend> ➝ 'Sat'|'Sun'// Four-character code// for day

Atomic Labels
The following are atomic labels, which are labels that refer to primitive data types. Whereavailable, the equivalent Microsoft C data type is also listed.

Label

Meaning

MS C Type<CHAR>

8-bit signed integer

signed char

<BYTE>

8-bit unsigned quantity

unsigned char<INT>

16-bit signed integer in Intel format

signed int<WORD>

16-bit unsigned quantity in Intel
formatunsigned int<LONG>

32-bit signed integer in Intel format

signed long

<DWORD>

32-bit unsigned quantity in Intel
formatunsigned long

<FLOAT>

32-bit IEEE floating point number

float<DOUBLE>

64-bit IEEE floating point number

double<STR>

String (a sequence of characters)<ZSTR>

NULL-terminated string

<BSTR>

String with byte (8-bit) size prefix<WSTR>

String with word (16-bit) size prefix<BZSTR>

NULL-terminated string with byte
size prefix<WZSTR>

NULL-terminated string with word
size prefix

NULL-terminated means that the string is followed by a character with ASCII value 0.
A size prefix is an unsigned integer, stored as a byte or a word in Intel format, that specifies thelength of the string. In the case of strings with BZ or WZ modifiers, the size prefix specifies thesize of the string without the terminating NULL.
Note: The WINDOWS.H header file defines the C types BYTE, WORD, LONG, and DWORD. These types
correspond to labels <BYTE>, <WORD>, <LONG>, and <DWORD>, respectively.

A Sample RIFF Form Definition and RIFF Form
The following example defines <GOBL-form>, the hypothetical RIFF form of type ‘GOBL’. To
fully document a new RIFF form definition, a developer would also provide detailed descriptionsof each file element, including the semantics of each chunk and sample files documented using thestandard notation.
<GOBL-form> ➝RIFF( 'GOBL'[<org-ck>]<obj-list>)// RIFF form header// Origin chunk (default (0,0,0))// Series of graphical objects<org-ck> ➝org(<origin:3D_POINT> )<obj-list> ➝

LIST(

'obj'

<sqr-ck> ➝sqr(<pt1:3D_POINT><pt2:3D_POINT><pt3:3D_POINT> )<circ-ck> ➝circ(<center:3D_POINT><circumPt:3D_POINT> )<poly-ck> ➝poly( <pt:3D_POINT>... )<3D_POINT> ➝struct{INT x;
INT y;
INT z;} 3D_POINT{// Object-list origin// An object is a:<sqr-ck> |<circ-ck> |<poly-ck> }... )// square,// circle,// or polygon// one vertex// another vertex// a third vertex// Center of circle// Point on circumference// List of points in a polygon// Defined in "gobl.h"// x-coordinate// y-coordinate// z-coordinate

Sample RIFF Form
The following sample RIFF form adheres to the form definition for form type GOBL. The filecontains three subchunks:•

An ‘INFO’ list•An ‘org’ chunk•An ‘obj’ chunkThe ‘INFO’ list and ‘org’ chunk each have two subchunks. The ‘INFO’ list is a registered global
chunk that can be used within any RIFF file. The ‘INFO’ list is described in the ‘INFO List
Chunk,” later in this chapter.
Since the definition of the GOBL form does not refer to the INFO chunk, software that expects
only ‘org’ and ‘obj’ chunks in a GOBL form would ignore the unknown ‘INFO’ chunk.
RIFF( 'GOBL'
LIST('INFO'// INFO list containing filename and copyright
INAM("A House"Z)ICOP("(C) Copyright Encyclopedia International 1991"Z))org(2, 0, 0))// Origin of object list

LIST('obj'// Object list containing two polygons
poly(0,0,0 2,0,0 2,2,0, 1,3,0, 0,2,0)poly(0,0,5 2,0,5 2,2,5, 1,3,5, 0,2,5))// End of form

Storing Strings in RIFF Chunks
This section lists methods for storing text strings in RIFF chunks. While these guidelines may not
make sense for all applications, you should follow these conventions if you must make anarbitrary decision regarding string storage.

NULL-Terminated String (ZSTR) Format
A NULL-terminated string (ZSTR) consists of a series of characters followed by a terminating
NULL character. The ZSTR is better than a simple character sequence (STR) because many
programs are easier to write if strings are NULL-terminated. ZSTR is preferred to a string with asize prefix (BSTR or WSTR) because the size of the string is already available as the <ckSize>value, minus one for the terminating NULL character.

String Table Format
In a string table, all strings used in a structure are stored at the end of the structure in packed
format. The structure includes fields that specify the offsets from the beginning of the string table
to the individual strings. An example follows:
typedef struct{
INT
iWidgetNumber;
WORD
offszWidgetName;
WORD
offszWidgetDesc;
INT
iQuantity;
CHAR
rgchStrTab[1];}
WIDGET;// the widget number// an offset to a string in <rgchStrTab>// an offset to a string in <rgchStrTab>// how many widgets// string table (allocate as large as needed)

If multiple chunks within the file need to reference variable-length strings, you can store thestrings in a single chunk that acts as a string table. The chunks that refer to the strings contain
offsets relative to the beginning of the data part of the string table chunk.

NULL-Terminated, Byte Size Prefix String (BZSTR) Series
In a BZSTR series, a series of strings is stored in packed format. Each string is a BZSTR, with abyte size prefix and a NULL terminator. This format retains the ease-of-use characteristics of the
ZSTR while providing the string size, allowing the application to quickly skip unneeded strings.

Multiline String Format
When storing multiline strings, separate lines with a carriage return/line feed pair (ASCII
13/ASCII 10 pair). Although applications vary in their requirements for new line symbols(carriage return only, line feed only, or both), it is generally easier to strip out extra characters thanto insert extra ones. Inserting characters might require reallocating memory blocks or pre-scanningthe chunk before allocating memory for it.

Choosing a Storage Method
The following lists guidelines for deciding which storage method is appropriate for yourapplication.

Usage

Recommended Format

Chunk data contains nothing except a string

ZSTR (NULL-terminated string) format.

Chunk data contains a number of fields, some ofwhich are variable-length strings

String-table format

Multiple chunks within the file need to reference
variable-length strings

String-table format

Chunk data stores a sequence of strings, some ofwhich the application may want to skip

BZSTR (NULL-terminated string withbyte size prefix) series

Chunk data contains multiline strings

A multiline string format

LIST ChunkA LIST chunk contains a list, or ordered sequence, of subchunks. A LIST chunk is defined asfollows:
LIST( <list-type> [<chunk>]... )The <list-type> is a four-character code that identifies the contents of the list.
If an application recognizes the list type, it should know how to interpret the sequence ofsubchunks. However, since a LIST chunk may contain only subchunks (after the list type), an
application that does not know about a specific list type can still walk through the sequence ofsubchunks.
Like chunk IDs, list types must be registered, and an all-lowercase list type has meaning relative
to the form that contains it. See “ Registering Multimedia Formats” in Chapter 1, “ Overview ofMultimedia Specifications,” for information on registering list types.

INFO List Chunk
The ‘INFO’ list is a registered global form type that can store information that helps identify thecontents of the chunk. This information is useful but does not affect the way a program interprets
the file; examples are copyright information and comments. An ‘INFO’ list is a ‘LIST’ chunk withlist type ‘INFO’. The following shows a sample ‘INFO’ list chunk:
LIST('INFO'INAM("Two Trees"Z)
ICMT("A picture for the opening screen"Z) )An ‘INFO’ list should contain only the following chunks. New chunks may be defined, but anapplication should ignore any chunk it doesn't understand. The chunks listed below may only
appear in an ‘INFO’ list. Each chunk contains a ZSTR, or null-terminated text string.

Chunk ID

Description

IARL

Archival Location. Indicates where the subject of the file is archived.

IART

Artist. Lists the artist of the original subject of the file. For example,“ Michaelangelo.”

ICMS

Commissioned. Lists the name of the person or organization thatcommissioned the subject of the file. For example, “ Pope Julian II.”

ICMTComments. Provides general comments about the file or the subject of the
file. If the comment is several sentences long, end each sentence with aperiod. Do not include newline characters.

ICOP

Copyright. Records the copyright information for the file. For example,“ Copyright Encyclopedia International 1991.” If there are multiple
copyrights, separate them by a semicolon followed by a space.

ICRD

Creation date. Specifies the date the subject of the file was created. List dates
in year-month-day format, padding one-digit months and days with a zero on

the left. For example, “ 1553-05-03” for May 3, 1553.
ICRP

Cropped. Describes whether an image has been cropped and, if so, how it was
cropped. For example, “ lower right corner.”

IDIM

Dimensions. Specifies the size of the original subject of the file. For example,“ 8.5 in h, 11 in w.”

IDPI

Dots Per Inch. Stores dots per inch setting of the digitizer used to produce thefile, such as “ 300.”

IENG

Engineer. Stores the name of the engineer who worked on the file. If there are
multiple engineers, separate the names by a semicolon and a blank. For
example, “ Smith, John; Adams, Joe.”

IGNR

Genre. Describes the original work, such as, “ landscape,” “ portrait,” “ still
life,” etc.

IKEY

Keywords. Provides a list of keywords that refer to the file or subject of the
file. Separate multiple keywords with a semicolon and a blank. For example,“ Seattle; aerial view; scenery.”

ILGT

Lightness. Describes the changes in lightness settings on the digitizer required
to produce the file. Note that the format of this information depends on
hardware used.

IMED

Medium. Describes the original subject of the file, such as, “ computer
image,” “ drawing,” “ lithograph,” and so forth.

INAM

Name. Stores the title of the subject of the file, such as, “ Seattle From
Above.”

IPLT

Palette Setting. Specifies the number of colors requested when digitizing animage, such as “ 256.”

IPRD

Product. Specifies the name of the title the file was originally intended for,such as “ Encyclopedia of Pacific Northwest Geography.”

ISBJ

Subject. Describes the conbittents of the file, such as “ Aerial view ofSeattle.”ISFT

Software. Identifies the name of the software package used to create the file,such as “ Microsoft WaveEdit.”

ISHP

Sharpness. Identifies the changes in sharpness for the digitizer required to
produce the file (the format depends on the hardware used).

ISRC

Source. Identifies the name of the person or organization who supplied theoriginal subject of the file. For example, “ Trey Research.”

ISRF

Source Form. Identifies the original form of the material that was digitized,
such as “ slide,” “ paper,” “ map,” and so forth. This is not necessarily thesame as IMED.

ITCHTechnician. Identifies the technician who digitized the subject file. For
example, “ Smith, John.”

CSET (Character Set) Chunk
To define character-set and language information for a RIFF file, use the CSET chunk. The CSET
chunk defines the code page and country, language, and dialect codes for the file. These values
can be overridden for specific file elements; see “ Usage Codes for Extra Header and Extra Entry
Fields,” later in this chapter, for information on specifying character set information in acompound file.
The CSET chunk is defined as follows:<CSET chunk> ➝ CSET( <wCodePage:WORD><wCountryCode:WORD><wLanguageCode:WORD><wDialect:WORD> )The fields are as follows:

Field

Description

wCodePage

Specifies the code page used for file elements. If the CSET
chunk is not present, or if this field has value zero, assume
standard ISO 8859/1 code page (identical to code page1004 without code points defined in hex columns 0, 1, 8,
and 9).

wCountryCode

Specifies the country code used for file elements. See“ Country Codes,” following this section, for a list of
currently defined country codes.
If the CSET chunk is not present, or if this field has value
zero, assume USA (country code 001).

wLanguage,
wDialect

Specify the language and dialect used for file elements. See“ Language and Dialect Codes,” later in this chapter, for alist of language and dialect codes.
If the CSET chunk is not present, or if these fields havevalue zero, assume US English (language code 9, dialect
code 1).

Country Codes
Use one of the following country codes in the wCountryCode field:

Country CodeCountry

000
001
002
003
030
031

None (ignore this field)
USA
CanadaLatin America
GreeceNetherlands

032
033
034
039
041
043
044
045
046
047
049
052
055
061
064
081
082
086
088
090
351
352
354
358

Belgium
FranceSpain
Italy
Switzerland
Austria
United Kingdom
Denmark
SwedenNorwayWest Germany
MexicoBrazilAustralia
New Zealand
Japan
Korea
People’s Republic of China
TaiwanTurkeyPortugal
Luxembourg
IcelandFinlandLanguage and Dialect Codes
Specify one of the following pairs of language-code and dialect-code values in the wLanguage
and wDialect fields:

Language CodeDialect Code

Language

0
1
2
3
4
4
5
6
7
7
8
9
9
10
10
11
12
12
12
12
13

0
1
1
1
1
2
1
1
1
2
1
1
2
1
2
1
1
2
3
4
1

None (ignore these fields)
ArabicBulgarian
CatalanTraditional Chinese
Simplified Chinese
Czech
DanishGermanSwiss German
Greek
US English
UK English
SpanishSpanish Mexican
FinnishFrenchBelgian French
Canadian French
Swiss French
Hebrew

14
15
16
16
17
18
19
19
20
20
21
22
22
23
24
25
26
26
27
28
29
30
31
32
33

1
1
1
2
1
1
1
2
1
2
1
1
2
1
1
1
1
2
1
1
1
1
1
1
1

Hungarian
Icelandic
ItalianSwiss ItalianJapanese
KoreanDutch
Belgian Dutch
Norwegian - Bokmal
Norwegian - Nynorsk
PolishBrazilian Portuguese
Portuguese
Rhaeto-Romanic
Romanian
Russian
Serbo-Croatian (Latin)
Serbo-Croatian (Cyrillic)
SlovakAlbanian
SwedishThai
TurkishUrdu
BahasaJUNK (Filler) Chunk
A JUNK chunk represents padding, filler or outdated information. It contains no relevant data; it isa space filler of arbitrary size. The JUNK chunk is defined as follows:<JUNK chunk> ➝ JUNK( <filler> )where <filler> contains random data.

Compound File Structure
The compound file structure is a RIFF-based structure upon which multimedia file formats can be
defined. The compound file structure is a parameterized structure that provides for the following:•

Storage of multimedia data elements•

Direct access to multimedia data elements (as opposed to sequential searching)

The goals of the compound file structure are to maximize flexibility and extensibility while
minimizing implementation costs. Using the compound file structure, developers of multimedia
data formats can define both simple and complex file formats.

The structure is flexible enough to be used for many purposes, but it can be simplified for use withsimple file formats. Designers of new multimedia file formats can restrict the use of standard
header fields, requiring some and removing others.
For example, a developer might define a compound file format that stores a series of bitmaps in asingle file, thus reducing compact disc seek times. Another developer might define a compound
file format that contains a special type of audio resource, using the compound file header
information to identify the attributes of the audio data stored within.

Structural Overview
Files based upon the compound file structure contain the following two RIFF chunks at their
topmost level:•

Compound File Table of Contents (CTOC) chunk•Compound File Element Group (CGRP) chunk

The CTOC chunk indexes the CGRP chunk, which contains the actual multimedia data elements.
Defined using the standard chunk notation, a compound file is represented as follows:<compound file> ➝ RIFF('type' <CTOC> <CGRP>)

where 'type' is a FOURCC indicating the file type.
This section describes the CTOC and CGRP chunks in detail.

Compound File Table of Contents (CTOC) Chunk
The CTOC chunk functions mainly as an index, allowing direct access to elements within acompound file. The CTOC chunk also contains information about the attributes of the entire fileand of each media element within the file.
To provide the maximum flexibility for defining compound file formats, the CTOC chunk can becustomized at several levels. The CTOC chunk contains fields whose length and usage is definedby other CTOC fields. This parameterization adds complexity, but it provides flexibility to fileformat designers and allows applications to correctly read data without necessarily knowing thespecific file format definition.

Structural Overview
The CTOC chunk defines the contents of the CGRP chunk. The CTOC chunk has the following
components:•

Header information defining the size of the CTOC chunk, the number of entries in the CGRP
chunk, the size of the CGRP chunk, and general information about the entire header file•

A parameter table definition defining the size and contents of the header parameter table andCTOC table entries•A header parameter table defining attributes that apply to the entire compound file.

•

CTOC table entries defining the location, size, name, and attributes of the compound fileelements contained in the CGRP chunk.

These components appear sequentially in the CTOC chunk. The individual fields in the CTOC
chunk are the following:<CTOC-chunk>➝ CTOC (<dwHeaderSize:DWORD><dwEntriesTotal:DWORD><dwEntriesDeleted:DWORD><dwEntriesUnused:DWORD><dwBytesTotal:DWORD><dwBytesDeleted:DWORD><dwHeaderFlags:DWORD>// Header information<wEntrySize:WORD>// Parameter table definition<wNameSize:WORD><wExHdrFields:WORD><wExEntFields:WORD><awExHdrFldUsage:WORD[wExHdrFields]><awExEntFldUsage:WORD[wExEntFields]>// Header parameter table<adwExHdrField:DWORD[wExHdrFields]>[<bHeaderPad:BYTE>][<CTOC-table-entry>]// CTOC table entries)

Each CTOC table entry is defined as follows:<CTOC-table-entry> ➝<dwOffset:DWORD><dwSize:DWORD><dwMedType:DWORD><dwMedUsage:DWORD><dwCompressTech:DWORD><dwUncompressBytes:DWORD><adwExEntField:DWORD[wExEntFields]><bEntryFlags:BYTE><achName:CHAR[wNameSize]>[<bEntryPad:BYTE>]...

The following sections describe each field in detail.

Header Information
The header information section defines general information about the CTOC header and about theentire compound file. It contains the following fields:

Field Name

Description

dwHeaderSize

Combined size of header information, parameter table definition, andheader parameter table. Use this value to locate the start of the
CTOC table entries within the CTOC chunk.

dwEntriesTotal

Total number of CTOC table entries, including unused entries andentries corresponding to deleted elements.

dwEntriesDeleted

Number of CTOC table entries that correspond to deleted elements.

dwEntriesUnused

Number of CTOC table entries that are unused.

dwBytesTotal

Combined size of all CGRP elements, including deleted elements.

dwBytesDeleted

Combined size of all deleted CGRP elements.

dwHeaderFlags

Flags that give information about the entire compound file. The
following flags may be used:
CTOC_HF_SEQUENTIAL
Valid CTOC table entries are arranged in sequential order. If
this flag is not set, the CTOC table entries may be in an arbitraryorder.
CTOC_HF_MEDSUBTYPE
The dwMedUsage field of each CTOC table entry contains a
FOURCC that indicates how the element is used. If this flag is
not set, the dwMedUsage field contains information as definedby the form type.

Parameter Table Definition
The parameter table definition defines the size and contents of the header parameter table andCTOC table. It contains the following fields:

Field Name

Description

wEntrySize

Size of each CTOC table entry, including any pad bytes.

wNameSize

Size of the achName field of each CTOC table entry. Each
achName field must be padded with null characters to this length.
The achName field is a null-terminated string, so it always contains
at least one trailing null character.

wExHdrFields

Number of extra header fields, or entries in the awExHdrFldUsageand adwExHdrField arrays.

wExEntFields

Number of extra entry fields, or entries in the awExEntFldUsageand adwExHdrField arrays.

awExHdrFldUsage

Array of extra header field usage fields. Each entry in this arraycorresponds to the same numbered entry in the adwExHdrField
array and defines how that entry is interpreted. Valid usage codes foreach field in this array are listed in “ Usage Codes for Extra Header
and Extra Entry Fields,” later in this chapter. The number of
WORDs in this array is defined by the wExHdrFields value.

awExEntFldUsage

Array of extra entry field usage fields. Each entry in this arraycorresponds to the same numbered entry in the adwExEntField
array, present in each CTOC table entry, and defines how that entry
is interpreted. Valid usage codes for each field in this array are listed
in “ Usage Codes for Extra Header and Extra Entry Fields,” later inthis chapter. The number of WORDs in this array is defined by thewExEntFields value.

Header Parameter Table
The header parameter table is an optional component generally used to define attributes of theentire compound file.

Field Name

Type

adwExHdrField

Extra header fields. The usage of each cell in the array is defined by
the corresponding cell in the awExHdrFldUsage array.
The number of DWORDs in this array is defined by thewExHdrFields value.

bHeaderPad

Zero or more NULL pad bytes. There must be enough padding inthis field to make the CTOC header an even number of bytes inlength.

CTOC Table Entries
The CTOC table entries define the location, size, name, and other information about the individualcompound file elements contained in the CGRP chunk. The number of CTOC table entries isdetermined by the dwEntriesTotal field in the header information of the CTOC chunk.

Each CTOC table entry is a structure containing the following fields:

Field Name

Description

dwOffset

Byte offset of the compound file element measured from the
beginning of the data portion of the CGRP chunk.
For example, if dwOffset is 1000 and the chunk ID of the CGRP
chunk is at offset 500, the element is at offset 1508 (1000+500+4(chunk ID)+4 (chunk size field)).

dwSizeSize of the element in bytes.

dwMedTypeFOURCC value identifying the media element type of the compound
file element. This field may be zero if the compound file element is
not to be interpreted as a standalone file. If the compound fileelement is a RIFF form, then the media element type is the same as
the RIFF form type.

dwMedUsage

Extra usage information for the compound file element.
If the CTOC_HF_MEDSUBTYPE flag is set in the dwHeaderFlags
field, this field contains a FOURCC that indicates how the element
is used. To avoid name conflicts, this FOURCC must be registered.
See “ Registering Multimedia Formats” in Chapter 1, “ Overview ofMultimedia Specifications,” for information on usage codes.
If the CTOC_HF_MEDSUBTYPE flag is not set in the
dwHeaderFlags field, this field contains 32 bits of informationinterpreted as defined by the form type.

dwCompressTech

Compression technique used to compress the media element. If thisvalue is zero, the element is not compressed. See “ Compression ofCompound File Elements,” later in this chapter, for more
information.

dwUncompressBytes

Number of bytes the compound file element occupies in memory
after decompression. This value assumes the decompression
technique identified in the dwCompressTech field. If the
dwCompressTech field is 0, then the compound file element is notcompressed, and this field should equal the dwSize field.

adwExEntField

Array of extra entry fields defining attributes of this compound fileelement. The usage of each cell in the array is defined by thecorresponding cell in the awExEntFldUsage array.
The number of DWORDs in this array is defined by thewExEntFields value.

bEntryFlags

Flags giving information about the compound file element or this
CTOC table entry. Possible values follow; these may be combined:
CTOC_EF_DELETED
Compound file is marked as deleted and should not be accessed.
Do not combine this flag with the CTOC_EF_UNUSED flag.
CTOC_EF_UNUSEDCTOC table entry is unused and does not refer to any compound
file element. This entry can be used to refer to a new compound
file element. Do not combine this flag with the
CTOC_EF_DELETED flag.

achNameArray of characters containing the name of the compound fileelement. The number of bytes in this array is defined by thewNameSize value.
The string must be padded on the right with NULL characters andmust be terminated by at least one NULL character. This field must
be an odd number of bytes in length and must be at least one bytelong.
bEntryPad

Zero or more NULL pad bytes as needed to make the table entry aneven number of bytes in length.

Usage Codes for Extra Header and Extra Entry Fields
The following are valid usage codes for elements in the awExHdrFldUsage andawExEntFldUsage arrays, both of which are fields of the CTOC header. These arrays define themeaning of data stored in the adwExHdrField and adwExEntField “ extra fields.” All usage
codes apply to both header fields and entry fields, unless explicitly stated otherwise.
Values marked in the extra header field arrays generally apply to all elements in the CFRG chunk,while values marked in the extra entry field arrays generally apply only to the element referenced
by the corresponding CTOC table entry.

Flag

Description

CTOC_EFU_UNUSED (0x00)

The field is unused. This usage code may be used tologically delete a header field.

CTOC_EFU_LASTMODTIME(0x01)

When used to describe an extra header field, the fieldcontains the time that any portion of the CTOC or CGRP
was last modified.
When used to describe an extra entry field, the fieldcontains the time that the corresponding CTOC table entry,
or the compound file element it refers to, was last modified.
The field is interpreted as a DWORD containing thenumber of seconds that have elapsed since 00:00:00
Greenwich Mean Time (GMT), January 1, 1970.

CTOC_EFU_CODEPAGE

The field contains the code page and country code for the
achName field. These values override any values specified
in a CSET chunk.
When used to describe an extra header field, the fieldcontains code-page and country-code information for all
CTOC table entries. When used to describe an extra entry
field, the field contains information for that specific CTOC
table entry.
The low-order word of the field contains one of thefollowing code page values:
Zero
Use standard ISO 8859/1 code page. This is identical tocode page 1004 without code points defined in hex
columns 0, 1, 8, and 9.
CTOC_CHARSET_CODEPAGE (0x0000nnnn)

Use code page 0xnnnn, where 0xnnnn is the 16-bit
code page number. For example, 0x00000352 for OS/2
code page 850, or 0x000004E4 for Windows 3.1 code
page 1252.
The high-order word contains one of the following country
codes:
Zero
Ignore this field.
Country code
See “ Country Codes,” earlier in this chapter, for a listof currently defined country codes.
CTOC_EFU_LANGUAGE

The field contains language and dialect information for the
achName field. These values override any values specified
in a CSET chunk.
When used to describe an extra header field, the fieldcontains language information for all CTOC table entries.
When used to describe an extra entry field, the fieldcontains information for that specific CTOC table entry.
The low-order word of the field contains one of thefollowing language codes:
Zero
Ignore this field.
Language code
See “ Language and Dialect Codes,” earlier in thischapter, for a list of currently defined language codes.
The high-order word of the field contains one of thefollowing dialect codes:
Zero
Ignore this field.
Dialect code
See “ Language and Dialect Codes,” earlier in thischapter, for a list of currently defined dialect codes.

CTOC_EFU_COMPRESSPARAM0(0x05) throughCTOC_EFU_COMPRESSPARAM9Specifies a compression parameter. See “ Compression ofCompound File Elements,” later in this chapter.

(0x14)

Compression of Compound File Elements
Compound file elements can be compressed. The dwCompressTech field of a CTOC table entry
contains a FOURCC compression technique identifier for the corresponding compound fileelement. If the field is zero, the compound file element is not compressed.
The definition of a specific compression technique may specify that either the entire compound
file element is compressed, or that some specific subset, for example one or more RIFF chunks, iscompressed.

The dwUncompressSize field contains the number of bytes that the compound file element will
occupy in memory after decompression. If the compound file element is not compressed, this fieldcontain the same value as the dwSize field, which identifies the file size of the compound fileelement.
Compression techniques may demand extra header fields or extra entry fields for decompression
parameters. Compression technique identifiers, and any new entry fields corresponding todecompression technique parameters, must be unique. See “ Registering Multimedia Formats” in
Chapter 1, “ Overview of Multimedia Specifications,” for information on registering compression
techniques.

Compound File Element Group (CGRP) Chunk
The actual elements of data referenced by the CTOC chunk are stored in a compound file Element
Group (CGRP) chunk. The CGRP chunk contains all the compound file elements, concatenated
together into one contiguous block of data. Some of the elements in the CGRP chunk might beunused, if the element was marked for deletion or was altered and stored elsewhere within the
CGRP chunk.
Elements within the CGRP chunk are of arbitrary size and can appear in a specific or arbitraryorder, depending upon the file format definition. Each element is identified by a corresponding
CTOC table entry.
Using the standard RIFF notation, the CGRP chunk is defined as follows:<CGRP-chunk> ➝ CGRP([<compound file element>]...)

Placement of the CTOC and CGRP Chunks
The specific file format definition can specify which of the two chunks appear first the data file.
Generally, the CTOC chunk is placed at the front of the file to reduce the seek and read times
required to access it. During authoring time, an application might place the CTOC chunk at theend of the file, so it can be expanded as elements are added to the CGRP chunk.

Chapter 3

Multimedia File Formats

This chapter describes the multimedia file formats. Most of these file formats are based on the
Resource Interchange File Format (RIFF), described in Chapter 2.
This chapter describes the following file formats:•

Bundle File Format (BND)•

Device Independent Bitmap File Format (DIB)•

RIFF DIB File Format (RDIB)•

Musical Instrument Digital Interface File Format (MIDI)•

RIFF MIDI File Format (RMID)•

Palette File Format (PAL)•

Rich Text Format (RTF)•

Waveform Audio File Format (WAVE)

Bundle File Format
The Bundle (BND) format contains a series of RIFF chunks or other multimedia files. The BND
file is defined as follows:<BND-file> ➝ RIFF('BND' <CTOC-chunk> <CGRP-chunk> )The <CTOC-chunk> and <CGRP-chunk> formats are defined in “ Compound File Structure,”
in Chapter 2, “ Resource Interchange File Format.”
Each compound file element must be capable of standing alone as an independent file. An element
may not be a random chunk (except the RIFF chunk, indicating a RIFF file) or random binary data
(unless the binary data is supposed to be treated as a file).

Device Independent Bitmap File Format
The Device Independent Bitmap (DIB) format represents bitmap images in a device-independent
manner. Bitmaps can be represented at 1, 4, and 8 bits per pixel, with a palette containing colors
represented in 24 bits. Bitmaps can also be represented at 24 bits per pixel without a palette and ina run-length encoded format.
This documentation describes three types of DIB files:•

Windows version 3.0 device-independent bitmap files•

OS/2 Presentation Manager version 1.2 device-independent bitmap files•

RIFF device-independent bitmap files

The Windows 3.0 and Presentation Manager 1.2 DIBs are similar, so they are discussed together.

Overview of DIB Structure
Windows 3.0 and Presentation Manager 1.2 DIB files consist of the following sequence of data
structures:•

A file header•

A bitmap information header•

A color table•

An array of bytes that defines the bitmap bits

The following sections describe each of these structures.

Bitmap File Header
The bitmap file header contains information about the type, size, and layout of a deviceindependent bitmap (DIB) file. In both the Windows 3.0 and Presentation Manager 1.2 DIBs, it isdefined as a BITMAPFILEHEADER data structure:
typedef struct tagBITMAPFILEHEADER {WORD
bfType;DWORD
bfSize;WORD
bfReserved1;
WORD
bfReserved2;
DWORD
bfOffBits;} BITMAPFILEHEADER;

The following table describes the fields.

Field

Description

bfTypeSpecifies the file type. It must consist of the character sequence BM(WORD value 0x4D42).
bfSizeSpecifies the file size in bytes.

bfReserved1

Reserved. Must be set to zero.

bfReserved2

Reserved. Must be set to zero.

bfOffBits

Specifies the byte offset from the BITMAPFILEHEADER structure
to the actual bitmap data in the file.

Bitmap Information Header
The BITMAPINFO and BITMAPCOREINFO data structures define the dimensions and color
information for Windows 3.0 and Presentation Manager 1.2 DIBs, respectively. They are defined
as follows:
Windows 3.0 DIB

Presentation Manager 1.2 DIB

typedef struct tagBITMAPINFO {BITMAPINFOHEADER bmiHeader;
RGBQUAD bmiColors[1];} BITMAPINFO;

typedef struct _BITMAPCOREINFO {BITMAPCOREHEADER
bmciHeader;
RGBTRIPLE bmciColors[1];} BITMAPCOREINFO;

These structures are essentially alike, and this section discusses them simultaneously. Each fieldname for the Windows BITMAPINFO structure is followed by the corresponding field name for
the Presentation Manager BITMAPCOREINFO 1.2 structure, in parentheses.
The following table describes the fields.

Windows (PM) Field

Description

bmiHeader(bmciHeader)Specifies information about the dimensions and color
format of the DIB. The BITMAPINFOHEADER and
BITMAPCOREHEADER data structures are described in
the next section.

bmiColors(bmciColors)

Specifies the DIB color table. The RGBQUAD and
RGBTRIPLE data structures are described in “ Bitmap
Color Table,” later in this chapter.

Information Header Structures
The BITMAPINFOHEADER and BITMAPCOREHEADER structures contain information about
the dimensions and color format of Windows 3.0 and Presentation Manager 1.2 DIBs,
respectively. They are defined as follows:

Windows 3.0 DIB

Presentation Manager 1.2 DIB

typedef struct tagBITMAPINFOHEADER {DWORD biSize;
DWORD biWidth;
DWORD biHeight;
WORD biPlanes;
WORD biBitCount;
DWORD biCompression;
DWORD biSizeImage;
DWORD biXPelsPerMeter;
DWORD biYPelsPerMeter;
DWORD biClrUsed;
DWORD biClrImportant;} BITMAPINFOHEADER;

typedef struct tagBITMAPCOREHEADER {DWORD
bcSize;WORD
bcWidth;WORD
bcHeight;
WORD
bcPlanes;
WORD
bcBitCount;} BITMAPCOREHEADER;

Because these structures are essentially alike, except for the added fields in the Windows 3.0
structure, this section discusses them simultaneously. Each field name for the Windows structure
is followed by the corresponding field name for the Presentation Manager structure, inparentheses.
Common Fields
The following fields are present in both the Windows 3.0 and Presentation Manager 1.2 formats:Windows (PM) Field

Description

biSize (bcSize)

Specifies the number of bytes required by the
BITMAPINFOHEADER structure. You can use this field
to distinguish between Windows 3.0 and Presentation
Manager 1.2 DIBs.

biWidth (bcWidth)

Specifies the width of the DIB in pixels.

biHeight (bcHeight)

Specifies the height of the DIB in pixels.

biPlanes (bcPlanes)

Specifies the number of planes for the target device. Must
must be set to 1.

wBitCount (bcBitCount)

Specifies the number of bits-per-pixel. See “ Interpreting
the Color Table,” later in this section, for more
information.

Windows Fields
The following fields are present only in the Windows 3.0 BITMAPINFOHEADER structure:

Field

Description

biCompression

Specifies the type of compression for a compressed bitmap. It can beone of the following values:
Value

Meaning

BI_RGB

Specifies that the bitmap is not compressed.

BI_RLE4

Specifies a run-length encoded format for bitmaps with
4 bits-per-pixel. The compression format is a two-byteformat consisting of a count byte followed by twoword-length color indexes.

BI_RLE8

Specifies a run-length encoded format for bitmaps with
8 bits-per-pixel. The compression format is a two-byteformat consisting of a count byte followed by a colorindex byte.

See “ Windows 3.0 Bitmap Compression Formats” later in thisdocument for information about the encoding schemes.
biSizeImage

Specifies the size in bytes of the image.

biXPelsPerMeter

Specifies the horizontal resolution in pixels per meter of the target
device for the bitmap. An application can use this value to select abitmap from a resource group that best matches the characteristics ofthe current device.

biYPelsPerMeter

Specifies the vertical resolution in pixels per meter of the target
device for the bitmap.

biClrUsed

Specifies the number of color values in the color table actually usedby the bitmap. Possible values follow.
Value

Result0

Bitmap uses the maximum number of colors
corresponding to the value of the wBitCount field.

NonzeroIf the wBitCount value is less than 24, the biClrUsed
value indicates the actual number of colors which thegraphics engine or device driver will access.
If the wBitCount value is 24, the biClrUsed value
indicates the size of the reference color table used to
optimize performance of Windows color palettes.

If the bitmap is a “ packed” bitmap (that is, a bitmap in which thebitmap array immediately follows the BITMAPINFO header andwhich is referenced by a single pointer), the biClrUsed field must be
set to 0 or to the actual size of the color table. See “ Interpreting theColor Table,” later in this section, for more information on how thisfield affects the interpretation of the color table.
biClrImportant

Specifies the number of color indexes that are considered important

for displaying the bitmap. If this value is 0, then all colors areimportant.

Bitmap Color Table
The color table is a collection of 24-bit RGB values. There are as many entries in the color table as
there are colors in the bitmap. The color table isn't present for bitmaps with 24 color bits because
each pixel is represented by 24-bit RGB values in the actual bitmap data area.

Color Table Structure
The color table for Windows 3.0 and Presentation Manager 1.2 DIBs consists of an array of
RGBQUAD and RGBTRIPLE structures, respectively. These structures are defined as follows:

Windows 3.0 DIB

Presentation Manager 1.2 DIB

typedef struct tagRGBQUAD {BYTE rgbBlue;BYTE rgbGreen;
BYTE rgbRed;
BYTE rgbReserved;} RGBQUAD;

typedef struct tagRGBTRIPLE {BYTE rgbtBlue;BYTE rgbtGreen;
BYTE rgbtRed;} RGBTRIPLE;

Because these structures are essentially alike, this section discusses them simultaneously. Eachfield name for the Windows RGBQUAD structure is followed by the corresponding field name for
the Presentation Manager RGBTRIPLE structure, in parentheses.

Order of Colors
The colors in the table should appear in order of importance. This can help a device driver render abitmap on a device that cannot display as many colors as there are in the bitmap. If the DIB is in
Windows 3.0 format, the driver can use the biClrImportant field of the BITMAPINFOHEADER
structure to determine which colors are important.

Field Descriptions
The RGBQUAD (RGBTRIPLE) structure contains the following fields:

Windows (PM) Field

Description

rgbBlue (rgbtBlue)

Specifies the blue intensity.

rgbGreen (rgbtGreen)

Specifies the green intensity.

rgbRed (rgbtRed)

Specifies the red intensity.

rgbReserved (no PM equivalent)

Not used. Must be set to 0.

Locating the Color Table
An application can use the biSize (bcSize) field of the BITMAPINFOHEADER(BITMAPCOREHEADER) structure to locate the color table. Each of the following statements
assigns the pColor variable the byte offset of the color table from the beginning of the file:// Windows 3.0 DIB
pColor = (LPSTR)pBitmapInfo + (WORD)pBitmapInfo->biSize// Presentation Manager 1.2 DIB
pColor = (LPSTR)pBitmapCoreInfo + (WORD)pBitmapCoreInfo->bcSize

Interpreting the Color Table
The biSize (bcSize) field of the BITMAPINFOHEADER (BITMAPCOREHEADER) structure
specifies how many bits define each pixel and specifies the maximum number of colors in thebitmap. Its value affects your interpretation of the color table.
The biSize (bcSize) field can have any of the following values:

Value

Meaning

1

The bitmap is monochrome, and the color table contains two entries. Each bit
in the bitmap array represents a pixel. If the bit is clear, the pixel is displayedwith the color of the first entry in the color table. If the bit is set, the pixel has
the color of the second entry in the table.

4

The bitmap has a maximum of 16 colors. Each pixel in the bitmap isrepresented by a four-bit index into the color table.
For example, if the first byte in the bitmap is 0x1F, then the byte represents
two pixels. The first pixel contains the color in the second table entry, and thesecond pixel contains the color in the 16th table entry.

8

The bitmap has a maximum of 256 colors. Each pixel in the bitmap isrepresented by a byte-sized index into the color table. For example, if the first
byte in the bitmap is 0x1F, then the first pixel has the color of the thirtysecond table entry.

24

The bitmap has a maximum of 224 colors. The bmiColors (bmciColors) field
is NULL, and each three bytes in the bitmap array represent the relative
intensities of red, green, and blue, respectively, of a pixel.

Note on Windows DIBs
For Windows 3.0 DIBs, the field of the BITMAPINFOHEADER structure specifies the number ofcolor indexes in the color table actually used by the bitmap. If the biClrUsed field is set to 0, thebitmap uses the maximum number of colors corresponding to the value of the field.

Bitmap Data
The bits in the array are packed together, but each line of pixels, or scan line, must be zero-padded
to end on a LONG boundary. When the bitmap is in memory, segment boundaries can appear
anywhere in the bitmap. The origin of the bitmap is the lower-left corner. The following section
discusses compression formats for the Windows 3.0 bitmap data.

Windows 3.0 Bitmap Compression Formats
Windows supports run-length encoded formats for compressing 4- and 8-bit bitmaps.
Compression reduces the disk and memory storage required for the bitmap. The following sections
describe the compression formats.

Compression of 8-Bit-Per-Pixel DIBs
When the biCompression field is set to BI_RLE8, the bitmap is compressed using a run-length
encoding format for an 8-bit bitmap. This format uses two modes:

RDIB’ form is defined as follows, using the standard RIFF form definition notation:<RDIB-form> ➝RIFF ('RDIB’ data( <DIB-data> ))The <DIB-data> format is defined in “ Device Independent Bitmap File Format,” earlier in thischapter.

Extended RDIB Format
The extended RDIB format, designed to incorporate enhancements such as compression, isdefined as follows:<RDIB-form> ➝RIFF('RDIB'<bmhd-ck>[ <pal-file> |<XPAL-ck>]<bitmap-data> )// Bitmap header chunk// Internal palette chunk// External palette chunk// Bitmap data

The <pal-file> chunk can be any of the palette-file formats discussed in “ Palette File Format,”later in this chapter. The <bmhd-ck>, <XPAL-chunk>, and <bitmap-data> are described in thefollowing sections.

Bitmap Header Chunk
The <bmhd-ck> bitmap header chunk is defined as follows:<bmhd-chunk> ➝ bmhd( struct {DWORD
dwMemSize;
DWORD
dwPelFormat;
WORD
wTransType;// If dwPelFormat is 'data', only these// four fields are present.

DWORD
DWORD
DWORD
DWORD
WORD
WORD
DWORD
DWORD
DWORD
DWORD
DWORD
DWORD

dwTransVal;
dwHdrSize;
dwWidth;dwHeight;
dwPlanes;
dwBitCount;dwCompression;dwSizeImage;
dwXPelsPerMeter;
dwYPelsPerMeter;
dwClrUsed;
dwClrImportant;// Fields from dwHdrSize forward match// the Windows BITMAPINFOHEADER// structure, though some fields can// contain new values.

} )If the dwCompression field equals BI_RGB or BI_RLE8 or BI_RLE4, then the extended RDIB
has the same bitmap format as a simple RDIB.
Each pixel format defines the orientation, or position of the bitmap origin. Windows bitmaps(identified by a value of ‘data’ in the dwPelFormat field) have the origin at the bottom left. By
default, the other formats have the origin at the top left.

Field

Description

dwMemSize

Equal to the size of the bitmap bits if the bits are uncompressed. For
RDIBs with dwPelFormat equal to ‘data,’ dwMemSize has one of thefollowing values:

dwPelFormat

Image Type

Field Value

Non-RLESame as dwSizeImage value

8-bit RLE

Size as an uncompressed, 8-bit image

4-bit RLE

Size as an uncompressed, 4-bit image

Specifies a FOURCC code defining the pixel format of the bitmap data.
The bitmap data is stored in a chunk (or chunks) that has the same
chunk ID as is contained in dwPelFormat. The compression schemeand pixel depth of the bitmap data are recorded in the dwCompression
and dwBitCount fields. The current bitmap data values are as follows:
Value

Bitmap Data Location and Format'data'

Bitmap data is stored in a ‘data’ chunk using the format
defined for Windows 3.0 device independent bitmaps(DIBs). An application can display the bitmap properly
even if the fields after (and including) dwMemSize are
ignored.

'palb'

Bitmap data is stored in a ‘palb’ chunk. The pixel format
is one of the Windows 3.0 RGB palettized formats (1 to 8
bpp, depending on the value of the dwBitCount field).

'rgbb'

Bitmap data is stored in a ‘rgbb’ chunk. Pixel format ispacked, unpalettized RGB represented at 16, 24, or 32
bits per pixel. The following shows the ordering of the
RGB bits for each pixel-depth value. The first extra bit (ifpresent) is the high-order bit.
dwBitCount

Extra

Red

Green

Blue

15
16
24
32
'yuvb'

wTransType

1
0
0
8

5
5
8
8

5
6
8
8

5
5
8
8

Bitmap data is stored in a ‘yuvb’ chunk. Pixel format ispacked, unpalettized YUV. The exact pixel format iscurrently undefined. By the time this draft is final, thepixel format will be defined similarly to the ‘rgbb’
definition.

Specifies the type of transparency representation, if any, used for thisimage. This is normally used for either image overlay applications,where one image may be visually on top of another, and all pels of thetransparency color should not be drawn. Examples include sprites, clip
art and motion video overlay. Wherever the transparency color occurs
in the picture, the background should be visible.
This information is stored with the image, so that multiple images that
use the same color map may all have different transparency color.
There are 5 different values for the transparency variable. These are:dwTransVal

Value

Result

BITT_NONE(0x0000)

No pels are considered transparent in thisimage.

BITT_MAPINDEX(0x0001)

One of the color map/palette entries should beconsidered the transparency color. All
instances of this pel should NOT be drawn,
and the existing background should beallowed to show through.

BITT_SINGLECOLOR(0x0002)

A single RGB or YUV value is consideredtransparent and should not be drawn.

BITT_BITPLANE(0x0003)

An individual bit plane is consideredtransparent, and all pels that have that bit orbits “ on” should not be drawn.

BITT_MULTILEVEL(0x0004)

A set of bits indicate multiple levels oftransparency or opacity. This is usually usedwith 32-bit RGB, where the high 8 bits
indicate transparency.

These bytes allow the image definition to indicate the exact information
about the transparent color. The information is dependent on the valueof the wTransType as follows:
wTransTypedwTransVal Contents

BITT_NONE

Not used.

BITT_MAPINDEX

Specifies a palette index, either 0 through 16
or 0 through 255, depending on the number ofpalette entries.

BITT_SINGLECOLOR

Specifies an RGB or YUV value (2 to 4 bytes
in size, depending on the pixel format

specified by dwPelFormat). All pels thatmatch dwTransVal should be consideredtransparent.
BITT_BITPLANE

Specifies a bit mask identifying the bits used
to indicate a transparent pel. Any pel that has
this set of bits set is totally transparent. This
allows multiple colors to be consideredtransparent. This method works for palettizedimages; in this case, the value refers to a map
entry that is considered transparent.

BITT_MULTILEVEL

Specifies bits to use for transparency levels.
These bits act as a mask on every pel, andeach pel can be matched to the mask todetermine the transparency level for the pel.
For example, if dwTransVal has value
0xFF000000, then there are 256 levels oftransparency. Each pel can be evaluatedagainst the mask. If the pel has a value
FFxxxxxx, then it is fully transparent. If thepel has a value 00xxxxxx, then it is fully
visible. If the pel has a value 7Fxxxxxx, thenthe pel is half visible.

dwHdrSize

Specifies the size of the data portion of the <bmhdr> chunk. This isalways 40, the size of the BITMAPINFOHEADER structure.

dwWidthSpecifies the width of the DIB in pixels.

dwHeight

Specifies the height of the DIB in pixels.

wPlanesSpecifies the number of planes. This value is normally 1, but it can be 3
or 4 for 24-bit RGB and 32-bit RGB images, respectively. In a
multiplane DIB, each color component (for example, red, green, andblue) is stored as a separate plane, and each plan is stored in a separate
bitmap data chunk. For example, in a 3-plane, 24-bit ‘rgbb’ bitmap, thered colors are stored in one ‘rgbb’ chunk, the green colors in a second‘rgbb’ chunk, and the blue colors in a third ‘rgbb’ chunk.
Allowing the separate RGB planes to be compressed independently candramatically improve the compression ratio. The wPlanes value mustbe 1 if dwPelFormat equals ‘data’.

wBitCount

Specifies the number of bits per pixel. If the dwPelFormat field equals‘data’, this field must contain values compatible with the Windows 3.0
DIB definition.

dwCompression

Specifies the type of compression for a compressed bitmap. It can beone of the following values:
Value

Meaning

BI_NONE(0xFFFF0000)

Specifies that the bitmap is not compressed. Pixel
values are not padded to four-byte boundaries.

BI_RGB(0x00000000)

Specifies that the bitmap is an uncompressed, 1-,4-, 8-, or a 24-bit image. For 24-bit images, thepalette is optional. Bitmap bits are represented as
defined by Windows 3.0 for BI_RGB DIBs. The

dwPelFormat field must be set to ‘data’.
BI_RLE8(0x00000001)

Specifies a run-length encoded, compressed
bitmap (as defined by Windows 3.0 BI_RLE8
DIBs). The palette is required. The dwPelFormat
field must be set to ‘data’.

BI_RLE4(0x00000002)

Specifies a run-length encoded, compressed
bitmap (as defined by Windows 3.0 BI_RLE4
DIBs). The palette is required. The dwPelFormat
field must be set to ‘data’.

BI_PACK(0xFFF0001)

Specifies a simple PACKBITS byte compression
scheme consisting of one-byte counts followed bybyte data, in the form:<count byte n><data byte1><data byte2>...<data byte n><count byte n><data byte to repeat>

The high-order bit of the count byte n is a decisionbit:n Value

Data Representationn < 0x80

A run of n+1 non-repeating bytes
follows.

n > 0x80

Data byte is repeated (n-0x80+1)
times.

n = 0x80

Reserved.

BI_TRANS(0xFFFF0002)

Specifies transitional compression, using a table ofbyte transitions or sequences. See “ Transitional
Compression,” following this table.

BI_CCC(0xFFFF0003)

Specifies CCC compression, a method involving
encoding each 4-by-4 block of the image using
two colors. See “ CCC Compression,” following
this table.

BI_JPEGN(0xFFFF0004)

To be defined later, when the ISO completes theofficial specification.

dwSizeImage

Specifies the size in bytes of the compressed image.

dwXPelsPerMeter

Specifies the horizontal resolution in pixels per meter of the target
device for the bitmap. An application can use this value to select abitmap from a resource group that best matches the characteristics ofthe current device. This field is set to zero if unused.

dwYPelsPerMeter

Specifies the vertical resolution in pixels per meter of the target device
for the bitmap. This field is set to zero if unused.

dwClrUsed

Specifies the number of palette entries actually used by the bitmap.
Possible values follow.
Value

Result0

Bitmap uses the maximum number of colors
corresponding to the value of the wBitCount field.

NonzeroIf the wBitCount is less than 24, dwClrUsed
specifies the actual number of colors which thegraphics engine or device driver will access.
If the wBitCount field is set to 24, dwClrUsed
specifies the size of the reference color table used
to optimize performance of Windows color
palettes.

dwClrImportant

Specifies the number of color indexes that are considered important for
displaying the bitmap. If this value is 0, then all colors are important.

Transitional Compression
If the dwCompression field is set to BI_TRANS, the data is transitionally compressed using atable of byte transitions or sequences. Values in the data indicate a table position to start at, andthe table provides continuing references to other table positions. Transitional compression applies
only to eight-bit data, either from an eight-bit palettized image or from a multi-plane image inwhich each color component is represented in eight bits.
The table consists of up to 256 16-byte rows at the beginning of the data section of the object.
Nibbles (half-bytes) in the data section indicate an offset into a table row, at which location isstored the actual byte value. The actual value then becomes the row applicable to the next data
nibble. The transitional encoding scheme is described more fully in a separate IBM document.
In transitional compression, the data section is a two-part compound object having the following
items:•A transition table•

The compressed image data

The transition table consists of an integer indicating the table size in bytes and a table of 16-byte
rows. The first byte in each row is a row number and the next 15 are transition values. Rows are indescending sequence. The image is compressed according to the following rules:•

Data is in nibbles (half-bytes) or in nibble-pairs (successive half-bytes which may cross a byteboundary).

•

The first byte is a nibble-pair. It is the first byte of the image and also the first row number.

•

Following a nibble-pair is a series of transition nibbles (1-15) ended by a terminator (0). Eachtransition nibble indicates an offset in the current row at which the next byte in the image isfound; this value is also the next row number.

•

The terminator indicates that the next image byte is not in the table, but instead in thefollowing nibble-pair. This value is also the next row number.

•If the picture has an odd number of nibbles (i.e., it ends in the first half of the last byte), an
extra zero nibble is included.

CCC Compression
TBD.

Palette ChunkA PLT chunk represents a color table and consists of a valid PAL file. The PAL file format isdefined in “ Palette File Format,” later in this chapter.

External Palette Chunk
Instead of a PLT chunk, an RDIB may contain an XPLT chunk, which indicates that the bitmap's
palette is stored outside the bitmap. The palette might be stored in a separate file or as a separate
compound file element. The XPLT chunk indicates the name and location of the external palettechunk and is defined as follows:<XPLT-chunk> ➝ XPLT(<fccLocation:FOURCC> <szPaletteName::ZSTR>)

The fccLocation contains one of the following FOURCC values specifying the location of theexternal chunk:fccLocation Value

Chunk Location‘full’

Palette is located in an external file, and the szPaletteName value
specifies a complete filename with path.

‘file’

Palette is located in an external file, and the szPaletteName value
specifies a filename without path.

‘elem’

Palette is located in the same compound file containing the DIB. The
szPaletteName value specifies the name of the compound fileelement.

The szPaletteName consists of a null-terminated string (ZSTR) containing the name of theexternal chunk containing the palette.

Bitmap Data Chunk
The <bitmap-data> contains bitmap data in the format specified by the biPelFormat field of the<bmhd-chunk>.

MIDI and RIFF MIDI File Formats
The Musical Instrument Digital Interface (MIDI) file format represents a Standard MIDI File, as
defined by the MIDI Manufacturers Association. A MIDI file contains commands instructing
instruments to play specific notes and perform other operations.
The specifications for MIDI and MIDI files can be obtained from the following organization:
International MIDI Association (IMA)
5316 W. 57th Street
Los Angeles, CA 90056(213) 649-6434.
The ‘RMID’ format consists of a standard MIDI file enclosed in a RIFF chunk. Enclosing the
MIDI file in a ‘RIFF’ chunk allows the file to be consistently identified; for example, an ‘INFO’list can be included in the file.
The ‘RMID’ form is defined as follows, using the standard RIFF form definition:<RMID-form>➝ RIFF ('RMID' data( <MIDI-data> ))The <MIDI-data> is equivalent to a Standard MIDI File.

Palette File Format
The Palette (PAL) File Format represents a logical palette, which is a collection of colors
represented as RGB values. There are two types of PAL formats:•

A simple PAL format•

An extended PAL format

Simple PAL Format
The simple PAL format is defined as follows:
RIFF('PAL' data( <palette:LOGPALETTE> ))LOGPALETTE is the Windows 3.0 logical palette structure, defined as follows:
typedef struct tagLOGPALETTE {WORD
palVersion;
WORD
palNumEntries;
PALETTEENTRY
palPalEntry[];} LOGPALETTE;

The LOGPALETTE structure fields are as follows:

Field

Description

palVersion

Specifies the Windows version number for the structure.

palNumEntries

Specifies the number of palette color entries.

palPalEntry[]

Specifies an array of PALETTEENTRY data structures that define
the color and usage of each entry in the logical palette.

The colors in the palette entry table should appear in order of importance. This is because entries
earlier in the logical palette are most likely to be placed in the system palette.
The PALETTEENTRY data structure specifies the color and usage of an entry in a logical color
palette. The structure is defined as follows:
typedef struct tagPALETTEENTRY {BYTE
peRed;BYTE
peGreen;
BYTE
peBlue;BYTE
peFlags;} PALETTEENTRY;

The PALETTEENTRY structure fields are as follows:

the bitmap's palette is stored outside the bitmap. The palette might be stored in a separate file or asa separate compound file element. The XPLT chunk indicates the name and location of theexternal palette chunk and is defined as follows:<XPLT-chunk> ➝ XPLT(<fccLocation:FOURCC> <szPaletteName::ZSTR>)

The fccLocation contains one of the following FOURCC values specifying the location of theexternal chunk:fccLocation Value

Chunk Location‘full’

Palette is located in an external file, and the szPaletteName value
specifies a complete filename with path.

‘file’

Palette is located in an external file, and the szPaletteName value
specifies a filename without path.

‘elem’

Palette is located in the same compound file containing the DIB. The
szPaletteName value specifies the name of the compound fileelement.

The szPaletteName consists of a null-terminated string (ZSTR) containing the name of theexternal chunk containing the palette.

Bitmap Data Chunk
The <bitmap-data> contains bitmap data in the format specified by the biPelFormat field of the<bmhd-chunk>.

MIDI and RIFF MIDI File Formats
The Musical Instrument Digital Interface (MIDI) file format represents a Standard MIDI File, as
defined by the MIDI Manufacturers Association. A MIDI file contains commands instructing
instruments to play specific notes and perform other operations.
The specifications for MIDI and MIDI files can be obtained from the following organization:
International MIDI Association (IMA)
5316 W. 57th Street
Los Angeles, CA 90056(213) 649-6434.
The ‘RMID’ format consists of a standard MIDI file enclosed in a RIFF chunk. Enclosing the
MIDI file in a ‘RIFF’ chunk allows the file to be consistently identified; for example, an ‘INFO’list can be included in the file.
The ‘RMID’ form is defined as follows, using the standard RIFF form definition:<RMID-form>➝ RIFF ('RMID' data( <MIDI-data> ))The <MIDI-data> is equivalent to a Standard MIDI File.

Palette File Format
The Palette (PAL) File Format represents a logical palette, which is a collection of colors
represented as RGB values. There are two types of PAL formats:•

A simple PAL format•

An extended PAL format

Simple PAL Format
The simple PAL format is defined as follows:
RIFF('PAL' data( <palette:LOGPALETTE> ))LOGPALETTE is the Windows 3.0 logical palette structure, defined as follows:
typedef struct tagLOGPALETTE {WORD
palVersion;
WORD
palNumEntries;
PALETTEENTRY
palPalEntry[];} LOGPALETTE;

The LOGPALETTE structure fields are as follows:

Field

Description

palVersion

Specifies the Windows version number for the structure.

palNumEntries

Specifies the number of palette color entries.

palPalEntry[]

Specifies an array of PALETTEENTRY data structures that define
the color and usage of each entry in the logical palette.

The colors in the palette entry table should appear in order of importance. This is because entries
earlier in the logical palette are most likely to be placed in the system palette.
The PALETTEENTRY data structure specifies the color and usage of an entry in a logical color
palette. The structure is defined as follows:
typedef struct tagPALETTEENTRY {BYTE
peRed;BYTE
peGreen;
BYTE
peBlue;BYTE
peFlags;} PALETTEENTRY;

The PALETTEENTRY structure fields are as follows:

Field

Description

peRed

Specifies the intensity of red for the palette entry color.

peGreenSpecifies the intensity of green for the palette entry color.

peBlueSpecifies the intensity of blue for the palette entry color.

peFlags

Specifies how the palette entry is to be used.

Extended PAL Format
The extended PAL format includes the following:•

A palette-header chunk•

A data chunk containing an RGB palette (consisting of a LOGPALETTE structure) or someother palette type, including YUV and XYZ palettes.

For an RGB palette, the extended PAL format is represented as follows:
RIFF('PAL' plth( <palette-header> ) data( <LOGPALETTE-data> ))For a YUV palette, the extended PAL format is represented as follows:
RIFF('PAL' plth( <palette-header> ) yuvp( <YUV-LOGPALETTE-data> ))Both the <LOGPALETTE-data> and <YUV-LOGPALETTE-data> use the Windows 3.0
LOGPALETTE structure, described in “ Simple PAL Format,” earlier in this section. The <YUVLOGPALETTE-data> contains YUV values instead of RGB values.
The ‘plth’ chunk is defined as follows:<plth-ck> ➝ PLT( struct {DWORD
dwMapType;
WORD
wWhite;WORD
wBlack;WORD
wBorder;
WORD
wRegisteredMap;
WORD
wCustomBase;
WORD
wCustomCnt;
WORD
wRsvBase;
WORD
wRsvCount;
WORD
wArtBase;
WORD
wArtCnt;
WORD
wNumIntense;} )// Fields from this point on are// optional. If they are included// but not used, set them to 0xFFFF.
// If an application encounters a// 'PLT' chunk smaller than shown// here, it should treat the missing// fields as unused.

The structure fields are described in the following:

Field

Description

dwMapTypeFOURCC code specifying the type of palette. Currently, the following
palette types are identified:
Code

Description‘data’

Specifies an RGB palette. Data chunk contains a
LOGPALETTE structure.

‘yuvp’

Specifies a YUV palette. Data chunk contains a YUV
palette.

‘xyzp’

Specifies an XYZ palette. Data chunk contains a XYZ
palette.

wWhitewBlackSpecify palette-map indices corresponding to the closest value of whiteand black. These identify the pair of colors with the best contrast for
use in cursors, calibration, etc. These values are usually changed if thepalette changes. Ignore these fields if they contain 0xFFFF.

wBorder

Specifies the index of the palette entry to be used for any displayborder regions, if supported by the display device. Ignore this field if it
contains 0xFFFF.

wRegisteredMap

Specifies how many palette entries correspond to a registered color
map. Registered entries are stored at the front of the palette. Ignore thisfield if it contains 0xFFFF.
Registered map entries are always stored at the beginning of the palette,
so wRegisteredMap also indicates the index of the first custom color
in the palette. Registered color maps include predefined palettes forgeneral use, forest/nature, or seasides. Currently defined values are thefollowing:
Value

Description

PAL_UNREGISTERED (0xFFFF)
Color map does not contain colors from a registered colormap.
PAL_VGA (0x0000)
Color map contains the standard 16 VGA colors.
PAL_AVC198 (0x0001)

Standard AVC 198-entry palette.

wCustomBase

Specifies the index of the first custom color of the palette. The
beginning of the palette contains the entries of the registered map, so
wCustomBase also indicates the number of entries in the registeredpalette. Map entries starting with wCustomBase comprise additionalcustom colors used in the bitmap. Ignore this value if
wRegisteredPalette is PAL_UNREGISTERED, or if wCustomBase
contains 0xFFFF.

wCustomCnt

Specifies the number of custom colors in the palette. Ignore this value
if wRegisteredPalette is PAL_UNREGISTERED, or if this fieldcontains 0xFFFF.

wRsvBase

Specifies the index of the first reserved color of the palette. Reservedcolors are those reserved for menus, text, and other screen elements.
Reserved colors must be stored contiguously. Ignore this field if it
contains 0xFFFF.

wRsvCnt

Specifies the number of reserved entries. Ignore this field if it contains
0xFFFF.

wArtBase

Specifies the index of the first art color of the palette. Art colors arecolors used for text and drawing. Art colors consist of a number ofhues, each of which has multiple intensities. The various intensities areused for anti-aliasing, a method of using different shades of a color to
improve the quality of images displayed on low-resolution devices.
For example, if the first art color is red anti-aliased to black with threeintensities, the first three entries in the palette would be dark red,medium red, and bright red. The art colors constitute an array, and allhues have the same number of intensities. The user can set both thenumber of hues and the number of intensities. Ignore these fields ifthey contain 0xFFFF.

wArtCnt

Specifies the number of art colors. Ignore this field if it contains
0xFFFF.

wNumIntense

Specifies the number of palette entries reserved for the anti-aliased
levels of a given art color. This field must be present if wArtBase ispresent. Ignore this field if it contains 0xFFFF.

Rich Text Format (RTF)
The Rich Text Format (RTF) is a standard method of encoding formatted text and graphics using
only 7-bit ASCII characters. Formatting includes different font sizes, faces, and styles, as well as
paragraph alignment, justification, and tab control.
RTF is described in the Microsoft Word Technical Reference: For Windows and OS/2, publishedby Microsoft Press.

Waveform Audio File Format (WAVE)This section describes the Waveform format, which is used to represent digitized sound.
The WAVE form is defined as follows. Programs must expect (and ignore) any unknown chunks
encountered, as with all RIFF forms. However, <fmt-ck> must always occur before<wave-data>, and both of these chunks are mandatory in a WAVE file.
<WAVE-form> ➝RIFF( 'WAVE'<fmt-ck>[<fact-ck>][<cue-ck>][<playlist-ck>][<assoc-data-list>]<wave-data> )// Format// Fact chunk// Cue points// Playlist// Associated data list// Wave data

The WAVE chunks are described in the following sections.

WAVE Format Chunk
The WAVE format chunk <fmt-ck> specifies the format of the <wave-data>. The <fmt-ck> isdefined as follows:<fmt-ck> ➝fmt(<common-fields> ➝struct
{
WORD
WORD
DWORD
DWORD
WORD
}

<common-fields><format-specific-fields> )wFormatTag;
wChannels;
dwSamplesPerSec;
dwAvgBytesPerSec;
wBlockAlign;// Format category// Number of channels// Sampling rate// For buffer estimation// Data block size

The fields in the <common-fields> chunk are as follows:

Field

Description

wFormatTag

A number indicating the WAVE format category of the file. The
content of the <format-specific-fields> portion of the ‘fmt’ chunk,and the interpretation of the waveform data, depend on this value.
You must register any new WAVE format categories. See“ Registering Multimedia Formats” in Chapter 1, “ Overview ofMultimedia Specifications,” for information on registering WAVE
format categories.
“ Wave Format Categories,” following this section, lists thecurrently defined WAVE format categories.

wChannels

The number of channels represented in the waveform data, such as 1
for mono or 2 for stereo.

dwSamplesPerSec

The sampling rate (in samples per second) at which each channel
should be played.

dwAvgBytesPerSec

The average number of bytes per second at which the waveform data
should be transferred. Playback software can estimate the buffer size
using this value.

wBlockAlign

The block alignment (in bytes) of the waveform data. Playback
software needs to process a multiple of wBlockAlign bytes of data at
a time, so the value of wBlockAlign can be used for bufferalignment.

The <format-specific-fields> consists of zero or more bytes of parameters. Which parameters
occur depends on the WAVE format category–see the following section for details. Playback
software should be written to allow for (and ignore) any unknown <format-specific-fields>parameters that occur at the end of this field.

WAVE Format Categories
The format category of a WAVE file is specified by the value of the wFormatTag field of the‘fmt’ chunk. The representation of data in <wave-data>, and the content of the<format-specific-fields> of the ‘fmt’ chunk, depend on the format category.
The currently defined open non-proprietary WAVE format categories are as follows:

wFormatTag Value

Format Category

WAVE_FORMAT_PCM (0x0001)

Microsoft Pulse Code Modulation (PCM) format

The following are the registered proprietary WAVE format categories:

wFormatTag Value

Format Category

IBM_FORMAT_MULAW (0x0101)

IBM mu-law format

IBM_FORMAT_ALAW (0x0102)

IBM a-law format

IBM_FORMAT_ADPCM (0x0103)

IBM AVC Adaptive Differential Pulse CodeModulation format

The following sections describe the Microsoft WAVE_FORMAT_PCM format.

Pulse Code Modulation (PCM) Format
If the wFormatTag field of the <fmt-ck> is set to WAVE_FORMAT_PCM, then the waveform
data consists of samples represented in pulse code modulation (PCM) format. For PCM waveform
data, the <format-specific-fields> is defined as follows:<PCM-format-specific> ➝struct{WORD
wBitsPerSample;}// Sample size

The wBitsPerSample field specifies the number of bits of data used to represent each sample ofeach channel. If there are multiple channels, the sample size is the same for each channel.
For PCM data, the wAvgBytesPerSec field of the ‘fmt’ chunk should be equal to the following
formula rounded up to the next whole number:
wChannels x wBitsPerSecond x

wBitsPerSample
8

The wBlockAlign field should be equal to the following formula, rounded to the next whole
number:wChannels x

wBitsPerSample
8

Data Packing for PCM WAVE Files
In a single-channel WAVE file, samples are stored consecutively. For stereo WAVE files, channel
0 represents the left channel, and channel 1 represents the right channel. The speaker position
mapping for more than two channels is currently undefined. In multiple-channel WAVE files,
samples are interleaved.
The following diagrams show the data packing for a 8-bit mono and stereo WAVE files:
Sample 1

Sample 2

Sample 3

Sample 4

Channel 0

Channel 0

Channel 0

Channel 0

Data Packing for 8-Bit Mono PCM

Sample 1
Channel 0(left)

Sample 2
Channel 1(right)Channel 0(left)

Channel 0(right)Data Packing for 8-Bit Stereo PCM

The following diagrams show the data packing for 16-bit mono and stereo WAVE files:
Sample 1

Sample 2

Channel 0

Channel 0

Channel 0

Channel 0

low-order byte

high-order byte

low-order byte

high-order byte

Data Packing for 16-Bit Mono PCM

Sample 1
Channel 0
Channel 1(left)(right)high-order byte
low-order byte

Channel 0(left)
low-order byte

Channel 1(right)high-order byte

Data Packing for 16-Bit Stereo PCM

Data Format of the Samples
Each sample is contained in an integer i. The size of i is the smallest number of bytes required tocontain the specified sample size. The least significant byte is stored first. The bits that represent
the sample amplitude are stored in the most significant bits of i, and the remaining bits are set tozero.
For example, if the sample size (recorded in nBitsPerSample) is 12 bits, then each sample isstored in a two-byte integer. The least significant four bits of the first (least significant) byte is set
to zero.
The data format and maximum and minimums values for PCM waveform samples of various sizes
are as follows:

Sample Size

Data Format

Maximum Value

Minimum Value

One to eight bits

Unsigned integer

255 (0xFF)

0Nine or more bits

Signed integer i

Largest positive valueof i

Most negative value ofiFor example, the maximum, minimum, and midpoint values for 8-bit and 16-bit PCM waveform
data are as follows:

FormatMaximum Value Minimum Value

Midpoint Value

8-bit PCM

255 (0xFF)

0128 (0x80)

16-bit PCM

32767 (0x7FFF)-32768 (-0x8000)

0

Examples of PCM WAVE Files
Example of a PCM WAVE file with 11.025 kHz sampling rate, mono, 8 bits per sample:
RIFF( 'WAVE'

fmt(1, 1, 11025, 11025, 1, 8)
data( <wave-data> ) )Example of a PCM WAVE file with 22.05 kHz sampling rate, stereo, 8 bits per sample:
RIFF( 'WAVE'

fmt(1, 2, 22050, 44100, 2, 8)
data( <wave-data> ) )Example of a PCM WAVE file with 44.1 kHz sampling rate, mono, 20 bits per sample:
RIFF( 'WAVE'INFO(INAM("O Canada"Z))
fmt(1, 1, 44100, 132300, 3, 20)data( <wave-data> ) )Storage of WAVE Data
The <wave-data> contains the waveform data. It is defined as follows:<wave-data> ➝<data-ck> ➝<wave-list> ➝samples<silence-ck> ➝{ <data-ck> | <data-list> }data( <wave-data> )LIST( 'wavl' {<data-ck> |// Wave<silence-ck> }... )// Silenceslnt( <dwSamples:DWORD> )// Count of// silent samples

Note: The ‘slnt’ chunk represents silence, not necessarily a repeated zero volume or baseline
sample. In 16-bit PCM data, if the last sample value played before the silence section is a 10000,
then if data is still output to the D to A converter, it must maintain the 10000 value. If a zero value
is used, a click may be heard at the start and end of the silence section. If play begins at a silence
section, then a zero value might be used since no other information is available. A click might becreated if the data following the silent section starts with a nonzero value.

FACT Chunk
The <fact-ck> fact chunk stores important information about the contents of the WAVE file. This
chunk is defined as follows:<fact-ck> ➝ fact( <dwFileSize:DWORD> )// Number of samples

The “ fact” chunk is required if the waveform data is contained in a “ wavl” LIST chunk and for
all compressed audio formats. The chunk is not required for PCM files using the “ data” chunkformat.
The "fact" chunk will be expanded to include any other information required by future WAVE
formats. Added fields will appear following the <dwFileSize> field. Applications can use the
chunk size field to determine which fields are present.

Cue-Points Chunk
The <cue-ck> cue-points chunk identifies a series of positions in the waveform data stream. The<cue-ck> is defined as follows:<cue-ck> ➝<cue-point> ➝cue(<dwCuePoints:DWORD><cue-point>... )// Count of cue points// Cue-point tablestruct {DWORD dwName;
DWORD dwPosition;
FOURCC fccChunk;
DWORD dwChunkStart;
DWORD dwBlockStart;
DWORD dwSampleOffset;}

The <cue-point> fields are as follows:

Field

Description

dwNameSpecifies the cue point name. Each <cue-point> record must have aunique dwName field.

dwPosition

Specifies the sample position of the cue point. This is the sequential
sample number within the play order. See “ Playlist Chunk,” later inthis document, for a discussion of the play order.

fccChunk

Specifies the name or chunk ID of the chunk containing the cue
point.

dwChunkStart

Specifies the file position of the start of the chunk containing the cue
point. This is a byte offset relative to the start of the data section ofthe ‘wavl’ LIST chunk.

dwBlockStart

Specifies the file position of the start of the block containing theposition. This is a byte offset relative to the start of the data sectionof the ‘wavl’ LIST chunk.

dwSampleOffset

Specifies the sample offset of the cue point relative to the start of theblock.

Examples of File Position Values
The following table describes the <cue-point> field values for a WAVE file containing multiple‘data’ and ‘slnt’ chunks enclosed in a ‘wavl’ LIST chunk:

Cue Point Location

Field

Value

In a ‘slnt’ chunkfccChunk

FOURCC value ‘slnt’.

dwChunkStart

File position of the ‘slnt’ chunk relative to thestart of the data section in the ‘wavl’ LIST
chunk.

dwBlockStart

File position of the data section of the ‘slnt’chunk relative to the start of the data sectionof the ‘wavl’ LIST chunk.

dwSampleOffset

Sample position of the cue point relative tothe start of the ‘slnt’ chunk.

fccChunk

FOURCC value ‘data’.

dwChunkStart

File position of the ‘data’ chunk relative to thestart of the data section in the ‘wavl’ LIST
chunk.

dwBlockStart

File position of the cue point relative to thestart of the data section of the ‘wavl’ LIST
chunk.

dwSampleOffset

Zero value.

fccChunk

FOURCC value ‘data’.

dwChunkStart

File position of the start of the ‘data’ chunk
relative to the start of the data section of the‘wavl’ LIST chunk.

dwBlockStart

File position of the enclosing block relative tothe start of the data section of the ‘wavl’ LIST
chunk. The software can begin thedecompression at this point.

dwSampleOffset

Sample position of the cue point relative tothe start of the block.

In a PCM ‘data’ chunk

In a compressed ‘data’chunk

The following table describes the <cue-point> field values for a WAVE file containing a single‘data’ chunk:

Cue Point Location

Field

Value

Within PCM data

fccChunk

FOURCC value ‘data’.

dwChunkStart

Zero value.

dwBlockStart

Zero value.

dwSampleOffset

Sample position of the cue point relative tothe start of the ‘data’ chunk.
In a compressed ‘data’chunk

fccChunk

FOURCC value ‘data’.

dwChunkStart

Zero value.

dwBlockStart

File position of the enclosing block relative tothe start of the ‘data’ chunk. The software canbegin the decompression at this point.

dwSampleOffset

Sample position of the cue point relative tothe start of the block.

Playlist Chunk
The <playlist-ck> playlist chunk specifies a play order for a series of cue points. The <playlistck> is defined as follows:<playlist-ck> ➝<play-segment> ➝plst(<dwSegments:DWORD><play-segment>... )// Count of play segments// Play-segment tablestruct {DWORD dwName;
DWORD dwLength;
DWORD dwLoops;}

The <play-segment> fields are as follows:

Field

Description

dwNameSpecifies the cue point name. This value must match one of thenames listed in the <cue-ck> cue-point table.

dwLength

Specifies the length of the section in samples.

dwLoopsSpecifies the number of times to play the section.

Associated Data Chunk
The <assoc-data-list> associated data list provides the ability to attach information like labels to
sections of the waveform data stream. The <assoc-data-list> is defined as follows:<assoc-data-list> ➝LIST('adtl'<labl-ck><note-ck><ltxt-ck>// Label// Note// Text withdata length<file-ck> )<labl-ck> ➝labl(<dwName:DWORD><data:ZSTR> )<note-ck> ➝note(<dwName:DWORD><data:ZSTR> )// Media file<ltxt-ck> ➝ltxt(<dwName:DWORD><dwSampleLength:DWORD><dwPurpose:DWORD><wCountry:WORD><wLanguage:WORD><wDialect:WORD><wCodePage:WORD><data:BYTE>... )<file-ck> ➝file(<dwName:DWORD><dwMedType:DWORD><fileData:BYTE>...)

Label and Note Information
The ‘labl’ and ‘note’ chunks have similar fields. The ‘labl’ chunk contains a label, or title, toassociate with a cue point. The ‘note’ chunk contains comment text for a cue point. The fields are
as follows:
Field

Description

dwNameSpecifies the cue point name. This value must match one of thenames listed in the <cue-ck> cue-point table.

dataSpecifies a NULL-terminated string containing a text label (for the‘labl’ chunk) or comment text (for the ‘note’ chunk).

Text with Data Length Information
The “ ltxt” chunk contains text that is associated with a data segment of specific length. The chunk
fields are as follows:
Field

Description

dwNameSpecifies the cue point name. This value must match one of thenames listed in the <cue-ck> cue-point table.

dwSampleLength

Specifies the number of samples in the segment of waveform data.

dwPurpose

Specifies the type or purpose of the text. For example, dwPurpose
can specify a FOURCC code like ‘scrp’ for script text or ‘capt’ forclose-caption text.

wCountry

Specifies the country code for the text. See “ Country Codes” in
Chapter 2, “ Resource Interchange File Format,” for a current list of
country codes.

wLanguage,
wDialect

Specify the language and dialect codes for the text. See “ Language
and Dialect Codes” in Chapter 2, “ Resource Interchange File
Format,” for a current list of language and dialect codes.

wCodePage

Specifies the code page for the text.

Embedded File Information
The ‘file’ chunk contains information described in other file formats (for example, an ‘RDIB’ fileor an ASCII text file). The chunk fields are as follows:
Field

Description

dwNameSpecifies the cue point name. This value must match one of thenames listed in the <cue-ck> cue-point table.

dwMedTypeSpecifies the file type contained in the fileData field. If the fileData
section contains a RIFF form, the dwMedType field is the same as
the RIFF form type for the file.
This field can contain a zero value.

fileData

Contains the media file.

Chapter 4Media Control Interface

The Media Control Interface (MCI) is a high-level command control interface to multimedia
devices and resource files. MCI provides applications with device-independent capabilities forcontrolling audio and visual peripherals. Your application can use MCI to control any multimedia
device, including audio playback and recording, as well as videodisc and videotape players.
MCI provides a standard command set for playing and recording multimedia devices and resource
files. Developers creating multimedia applications are encouraged to use this high-level commandinterface rather than the low-level functions specific to each platform. The MCI command set acts
as a platform-independent layer that sits between multimedia applications and the underlying
system software.
The command set is extensible in two ways:•

Developers can incorporate new multimedia devices and file formats in the MCI command set
by creating new MCI drivers to interpret the commands.

•

New commands and command options can be added to support special features or functions
required by new multimedia devices or file formats.

MCI Command Strings
Using MCI, an application can control multimedia devices using simple command strings like
open, play, and close. The MCI commands provide a generic interface to different multimedia
devices, reducing the number of commands a developer needs to learn. A multimedia application
might even accept MCI commands from an end user and pass them unchanged to the MCI driver,which parses the command and performs the appropriate action.
A set of basic commands is supported by all MCI devices. Developers can also define MCI
commands and command options specific to a particular multimedia device or file format. These
device-specific commands and command options are needed only when the basic command set
does not support a feature specific to the device or file format.

Example of MCI Command Use
The following example shows a series of MCI commands that play track 6 of an audio compact
disc:
open cdaudio
set cdaudio time format tmsf
play cdaudio from 6 to 7
close cdaudio

The next example shows a similar series of MCI commands that play the first 10,000 samples of a
waveform audio file:
open c:\mmdata\purplefi.wav type waveaudio alias finch
set finch time format samples
play finch from 1 to 10000 wait
close finch

Notice the following:•

The same basic commands (open, play, and close) are used with both devices.

•

The open command for the “ waveaudio” device includes a filename specification. The“ waveaudio” device is a compound device (one associated with a media element), while the“ cdaudio” device is a simple device (one without an associated media element).

•

The set commands both specify time formats, but the time format options for the “ cdaudio”
device are different from those used with the “ waveaudio” device.

•

The parameters used with the from and to flags are appropriate to the respective device. For
the “ cdaudio” device, the parameters specify a range of tracks; for the “ waveaudio” device,
the parameters specify a range of samples.

Categories of MCI Command Strings
MCI command strings divide into the following categories:•

System commands are interpreted directly by MCI rather than being relayed to a device.

•

Required commands are recognized by all MCI devices. If a device does not support arequired command, it can return “ unsupported function” in response to the message.

•

Basic commands are optional commands. If a device uses a basic command, it must respondto all options for that command. If a device does not use a basic command, it can return“ unrecognized command” in response to the message.

•

Extended commands are specific to a device type or device class; for example, videodisc
players. These commands contain both unique commands and extensions to the required andbasic commands.

Command Syntax Conventions
This chapter uses the following documentation conventions:

Convention

Descriptionbold

MCI command or flag keyword.

italics

Command parameter to be replaced with a valid string, number, or rectangle
specification.

“ quotes”

Parameter text to be typed exactly as shown.

[ brackets ]Optional flags or parameters

System Commands
The following list summarizes the system commands. MCI supports these commands directly
rather than passing them to MCI devices.

Message

Description

soundPlay system sounds defined in a system setup file.

sysinfo

Returns information about MCI devices.

Required Commands
The following list summarizes the required commands. All devices recognize these messages. If adevice does not support a required command, it can return “ unsupported function” in response to
the message.

Message

Description

capability

Obtains the capabilities of a device.

close

Closes the device.

info

Obtains textual information from a device.

open

Initializes the device.

statusReturns various status information from the device.

Basic Commands
The following list summarizes the basic commands. MCI devices are not required to recognize
these commands. If the device does not recognize a basic command, it can return “ unrecognizedcommand” in response to the message.

Message

Description

load

Recalls data from a disk file.

pause

Stops playing.

play

Starts transmitting output data.

recordStarts recording input data.

resumeResumes playing or recording from a paused state.

save

Saves data to a disk file.

seek

Seeks forward or backward.

set

Sets the operating state of the device.

statusObtains status information about the device. (The flags for this command
supplement the flags for the command in the required command group.)

stop

Stops playing.

Extended Commands
MCI devices can have additional commands or extend the definition of the required and basic
commands. While some extended commands only apply to a specific device driver most of them
apply to all devices of a particular type. For example, the MIDI sequencer command set extends
the set command to add time formats needed by MIDI sequencers.You can find descriptions ofextended commands in the command tables in this chapter.

Extended Commands Reserved for Future Use
The following commands can be defined as extended commands. With the exception of the deletecommand, they are not currently defined for any MCI devices.

Message

Description

copy

Copies data to the Clipboard. Parameters and flags for this message vary
according to the selected device.

cut

Moves data from the MCI element to the Clipboard. Parameters and flags forthis message vary according to the selected device.

deleteRemoves data from the MCI element. Parameters and flags for this message
vary according to the selected device.

Creating a Command String
There are three components associated with each command string: the command, the name or IDof the device receiving the command, and the command arguments. A command string has thefollowing form:
command device_namearguments

These components contain the following information:•

The command includes a command from the system, required, basic, or extended commandset. Examples of commands include open, close, and play.

•

The device_name designates the target of the command. MCI accepts the names of MCI
device types and names of media elements for the device_name. An example of a devicename is “ cdAudio” .

•The arguments specify the flags and parameters used by the command. Flags are key words
recognized by the MCI command, and parameters are variables associated with the MCI
command or flag. Parameters specify variable data values such as filenames, track or frame
numbers, or speed values. You can use the following data types for the parameters in a string
command:•

Strings–String data types can be delimited by leading and trailing white space or bymatching quotation marks. If MCI encounters a single (unmatched) quotation mark, itignores the quotation mark. To embed a quote in string, use two quotes (""). To specify
an empty string, you can use double quotes ("") for the string.

•

Signed long integers–Signed long integer data types are delimited by leading and trailingwhite space. Unless otherwise specified, integers can be positive or negative. If using
negative integers, do not embed white space between the negative sign and the first digit.

•

Rectangle–Rectangle data types are an ordered list of four signed integer values. White
space delimits this data type as well as separates each integer in the list.

For example, the play command uses the arguments “ from position to position” to specify
starting and ending points for the playback. The from and to arguments are flags, and the two
position values are parameters.
For example, the following command string instructs the CD audio player “ cdaudio” to play fromthe start of the waveform to position 500:
play cdaudio from 0 to 500

Unspecified command arguments assume a default value. For example, if the flag from wasunspecified in the previous example, the audio player would start playing at the current position.

About MCI Device Types
Your application identifies an MCI device by specifying an MCI device type. A device typeindicates the physical type of device. The following table lists the currently defined MCI device
types:

Device Type

Description

cdaudio1

CD audio player

dat

Digital audio tape player

digitalvideo

Digital video in a window (not GDI based)

other

Undefined MCI device

scanner

Image scanner

sequencer1

MIDI sequencer

vcr

Videotape recorder or player

videodisc1

Videodisc player

waveaudio1

Audio device that plays digitized waveform files

1An extended command set is provided for these devices.

If you have a particular device type installed more than once, the device type names in the systemsetup file have integers appended to them. This creates unique names for each MCI device type
entry. For example, if the “ cdaudio” device type is installed twice, the names “ cdaudio1” and“ cdaudio2” are used to create unique names for each occurrence of the device type. Each nameusually refers to a different CD audio player in the system.

Using MCI Command Strings
The tables at the end of this chapter describe command strings for the MCI devices. The following
sections describe commonly used command strings.

Opening a Device
Before using a device, you must initialize it with the open command. The number of devices you
can have open depends on the amount of available memory. The open command has the following
syntax:open device_name [shareable] [type device_type] [ alias alias ]The parameters for the open command are:Parameters

Description

device_nameSpecifies the destination device or MCI element name (filename).

shareable

Allows applications to share a common device or device element.

type device_type

Specifies the device when the device_name refers to an MCI
element.

alias alias

Specifies an alternate name for the device.

MCI classifies device drivers as compound and simple. Compound device drivers use a device
element–a media element associated with a device–during operation. For most compound device
drivers, the device element is the source or destination data file. For file elements, the element
name references a file and its path.
Simple device drivers do not require a device element for playback. For example, compact discaudio device drivers are simple device drivers.

Opening Simple Devices
Simple devices require only the device_name for operation. You don't need to provide any
additional information (such as a name of a data file) to open these devices. For these devices,
substitute the name of a device type obtained from the system setup file. For example, you can
open a videodisc device with the following command:
open videodisc1

Opening Compound Devices
There are three ways to open a compound device:•

By specifying just the device type•

By specifying both the element name and the device type•

By specifying just the element nameTo determine the capabilities of a device, you can open a device by specifying only the device
type. When opened this way, most compound devices will let you determine their capabilities andclose them. For example, you can open the sequencer with the following command:
open sequencer

To associate a device element with a particular device, you must specify the element name anddevice type. In the open command, substitute the element name for the device_name, add the typeflag, and substitute the name of the device you want to use for device_type. This combination lets
your application specify the MCI device it needs to use. For example, you can open a device
element of the waveaudio device with the following command:open

right.wav

type

waveaudio

To associate a default MCI device with a device element, you can specify just an element name. In
this case, MCI uses the filename extension of the element name to select the device type.

Using the Shareable Flag
The shareable flag lets multiple applications or tasks concurrently access the same device (orelement) and device instance.
If your application opens a device or device element without the shareable flag, no otherapplication can access it simultaneously. If your application opens a device or device element asshareable, other applications can also access it by also opening it as shareable. The shared device
or device element gives each application the ability to change the parameters governing theoperating state of the device or device element. Each time that a device or device element is
opened as shareable, a unique device ID is returned (even though the device IDs refer to the same
instance)
If you make a device or device element shareable, your application should not make any
assumptions about the state of a device. When working with shared devices, your application
might need to compensate for changes made by other applications using the same services.
If a device can service only one application or task it will fail an open with the shareable flag.
While most compound device elements are not shareable, you can open multiple elements (where
each element is unique), or you can open a single element multiple times. If you open a single fileelement multiple times, MCI creates an independent instance for each open device. Each fileelement opened within a task must have a unique name. The alias flag described in the next
section lets you use a unique name for each element.

Using the Alias Flag
The alias flag specifies an alternate name for the given device. The alias provides a shorthandnotation for compound devices with lengthy pathnames. If your application creates a device alias,
it must use the alias rather than the device name for all subsequent references.

Opening New Device Elements
To create a new device element for a task such as capturing a sound using waveform recording,specify new as a device_name. MCI does not save a new file element until you save it with thesave command. When creating a new file, you must include a device alias with the open
command. The following commands open a new waveaudio device element, start and stop
recording, save the file element, and close the device element:
open new type waveaudio alias capturerecord capture
stop capture
save capture orca.wav
close capture

Closing a Device
The close command releases access to a device or device element. To help MCI manage thedevices, your application must explicitly close each device or device element when it is finishedwith it.

Shortcuts and Variations for MCI Commands
The MCI string interface lets you use several shortcuts when working with MCI devices.

Using All as a Device NameYou can specify all as a device_name for any command that does not return information. Whenyou specify all, the command is sent to all devices opened by your application. For example,“ close all” closes all open devices and “ play all” starts playing all devices opened by the task.
Because MCI sends the commands to each device, there is a delay between when the first device
receives the command and when the last device receives the command.

Combining the Device Type and Device Element NameYou can eliminate the type flag in the open command if you combine the device type with thedevice element name. MCI recognizes this combination when you use the following syntax:
device_type!element_name
The exclamation mark separates the device type from the element name. The following example
opens the right.wav element with the waveaudio device:
open waveaudio!right.wav

Automatic OpenIf MCI cannot identify the device_name as an already open device, MCI tries to automatically
open the specified device. Automatic open does not let your application specify the type flag. If
the device type is not supplied, MCI determines the device type from the element (filename)extensions listed in the system setup file. If you want to use a specific device, you can combine thedevice type name with the device element name using the exclamation mark.
Only the command-string interface supports automatic open. Automatic open will fail for devicespecific commands. For example, a command to unlock the front panel of a videodisc player will
fail an automatic open because this capability is specific to the particular videodisc player.
A device that was opened using the automatic open feature will not respond to a command thatuses all as a device name.

Automatic Close
MCI automatically closes any device automatically opened using the command-string interface.
MCI closes a device when the command completes, when you abort the command, when you
request notification with a subsequent command, or when MCI detects a failure.

Using Wait and Notify Flags
Normally, MCI commands return to the user immediately, even if it takes several minutes tocomplete the action initiated by the command. For example, after a VCR device receives a rewindcommand, it returns before the tape has finished rewinding. You can use either of the following
required MCI flags to modify this default behavior:

Flag

Description

notifyDirects the device to send an MM_MCINOTIFY message to awindow when the requested action is complete.

wait

Directs the device to wait until the requested action is complete
before returning to the application.

Using the Notify Flag
The notify flag directs the device to post an MM_MCINOTIFY message when the device
completes an action. Your application must have a window procedure to process the
MM_MCINOTIFY message for notification to have any effect. While the results of a notification
are application-dependent, the application's window procedure can act upon four possible
conditions associated with the notify message:•

Notification will occur when the notification conditions are satisfied.

•

Notification can be superseded.

•

Notification can be aborted.

•

Notification can fail.

A successful notification occurs when the conditions required for initiating the callback aresatisfied and the command completed without interruption.
A notification is superseded when the device has a notification pending and you send it anothernotify request. When a notification is superseded, MCI resets the callback conditions tocorrespond to the notify request of the new command.
A notification is aborted when you send a new command that prevents the callback conditions set
by a previous command from being satisfied. For example, sending the stop command cancels anotification pending for the “ play to 500” command. If your command interrupts a command thathas a notification pending, and your command also requests notification, MCI will abort the first
notification immediately and respond to the second notification normally.
A notification fails if a device error occurs while a device is executing the MCI command. For
example, MCI posts this message when a hardware error occurs during a play command.

Obtaining Information From MCI Devices
Every device responds to the capability, status, and info commands. These commands obtain
information about the device. For example, your application can determine if a videodisc requiresa device element using the following command:
capability videodisc compound fileFor most videodisc devices, this example would return false. The flags listed for the required andbasic commands provide a minimum amount of information about a device. Many devices
supplement the required and basic flags with extended flags to provide additional information
about the device.
When you request information with the capability, status, or info command, the argument list cancontain only one flag requesting information. The string interface can only return one string orvalue in response to a capability, status, or info command.

The Play Command
The play command starts playing a device. Without any flags, the play command starts playing
from the current position and plays until the command is halted or until the end of the media orfile is reached. For example, “ play cdaudio” starts playing an audio disc from the position where
it was stopped.
Most devices support the play command also support the from and to flags. These flags indicate
the position at which the device should start and stop playing. For example, “ play cdaudio from0” plays the audio disc from the beginning of the first track. The units assigned to the position
value depend on the device. For example, the position is normally specified in frames for CAV
videodiscs, and milliseconds for digital audio.
As an extended command, devices add flags to use the capabilities of a particular device. For
example, the play command for videodisc players adds the flags fast, slow, reverse, and scan.

Stop, Pause, and Resume Commands
The stop command suspends the playing or recording of a device. Many devices include the basic
command pause, which also suspends these sessions. The difference between stop and pause
depends on the device. Usually pause suspends operation but leaves the device ready to resume
playing or recording immediately.
Using play or record to restart a device will reset the to and from positions specified before thedevice was paused or stopped. Without the from flag, these commands reset the start position to
the current position. Without the to flag, they reset the end position to the end of the media. If you
want to continue playing or recording but want to stop at a position previously specified, use theto flag with these commands and repeat the position value.
Some devices include the resume command to restart a paused device. This command does notchange the to and from positions specified with the play or record command, which preceded thepause command.

MCI System Commands
The following commands are interpreted directly by MCI. The remaining command tables list
commands interpreted by the devices.

Command

Description

sound

The device name of this command specifies a sound defined in a systemsetup file.. If it is not found, MCI uses a system default sound.

sysinfo item

Obtains MCI system information. One of the following items modifies
sysinfo:installname

Returns the name used to install the device.

quantity

Returns the number of MCI devices of the typespecified by the device-name field. The devicename field must contain a standard MCI device
type. Any digits after the name are ignored. The
special device name all returns the total number of
MCI devices in the system.

quantity open

Returns the number of open MCI devices of thetype specified by the device name. The devicename must be a standard MCI device type. Any
digits after the name are ignored. The special
device name all returns the total number of MCI
devices in the system that are open.

name index

Returns the name of an MCI device. The index
ranges from 1 to the number of devices of thattype. If all is specified for the device name, index
ranges from 1 to the total number of devices in thesystem.

name index open

Returns the name of an open MCI device. The
index ranges from 1 to the number of devices ofthat type. If all is specified for the device name,index ranges from 1 to the total number of devices
in the system.

Required Commands for All Devices
The following commands are recognized by all devices. Extended commands can add otheroptions to these commands. A list of the errors common to all the commands follows the requiredcommand table.

Command

Description

capability item

Requests information about a particular capability of a device. While othercapabilities are defined for specific devices and device types, the following
items are always available:
can eject

Returns true if the device can eject the media.

can play

Returns true if the device can play.

can record

Returns true if the device supports recording.

can save

Returns true if the device can save data.

compound device

Returns true if the device requires an element
name.

device type

Returns one of the following:audio tapecdaudio
digital audio tapescannersequencer
videodiscvideotape
waveaudio

has audio

Returns true if the device supports audio
playback.

has video

Returns true if the device supports video.

uses files

Returns true if the element of a compound device
is a file pathname.

close

When sent to a simple device, closes the device. When sent to a compounddevice element, closes the element and any resources associated with it.
MCI unloads a device when it is no longer being used.

info item

Fills a user-supplied buffer with a NULL-terminated string containing
textual information. One of the following item modifies info:
product

open items

Returns a description of the hardware associatedwith a device. This usually includes the
manufacturer and model information.

Initializes the device. The following optional items modify open:
alias device alias

Specifies an alternate name for the given device. If
specified, it must be used for subsequent
references.

shareable

Initializes the device or element as shareable.
Subsequent attempts to open it fail unless youspecify shareable in both the original andsubsequent open commands. MCI returns an error
if it is already open and not shareable.
type device typestatus item

Specifies the compound device that controls adevice element. As an alternative to type, MCI can
use the filename extension entries to select thedevice based on the extension used by the device
element.

Obtains status information for the device. One of the following items
modifies status:
mode

Returns the current mode of the device.
Commonly supported standard modes are: notready, paused, playing, stopped, open,
recording, and seeking

ready

Returns true if the device is ready.

Basic Commands for Specific Device Types
In addition to the commands described previously, each device supports a set of commands
specific to its device type. Where possible, these type-specific commands are identical between
types. When type-specific commands are common to multiple devices, they are considered basic
commands. For example, the basic play command is identical for videodisc and videotape players.
Other basic commands are listed in the following table. Although these commands are optional fora device, if a command is used it must recognize all options listed in this table. The options
generally provide for a minimum set of capabilities, but some devices may return “ unsupported
function” if an option is used which clearly doesn’t apply.

Command

Description

load item

Load a device element from disk. The following optional item modifies
load:
filename

Specifies the source path and file.

pause

Pauses playing or recording.

play items

Start playing the device. The following optional items modify play:from position
to position

Specifies the position to start and stop
playing. If from is omitted, the play starts
from the current position; if to is omitted, theplay stops at the end of the media.

record items

Start recording data. All data recorded after a file is opened is discarded
if the file is closed without saving it. The following optional items
modify record:
insertSpecifies that new data is added to the device
element at the current position.

from position
to position

Specifies the positions to start and stop
recording. If from is omitted, the device starts
recording at the current position; if to isomitted, the device records until a stop or
pause command is received.

overwrite

Specifies that new data will replace data in thedevice element.

The default recording mode (insert or overwrite) depends on thespecific device. Each device should define a default recording mode.
resumeResumes playing or recording following a pause.

save item

Saves the MCI element. The following optional item modifies save:
filenameseek item

set items

status item

Specifies the destination path and file.

Moves to the specified position and stops. One of the following isrequired for item :to position

Specifies the position to stop the seek.

to start

Seeks to the start of the media or device
element.

to endSeeks to the end of the media or device
element.

Sets the various control items:
audio all off
audio all on

Enables or disables audio output

audio left off
audio left on

Enables or disables output to the left audio
channel.

audio right off
audio right on

Enables or disables output to the right audio
channel.

door closed

Loads the media and closes the door if
possible.

door open

Opens the door and ejects the tray if possible.

time format
milliseconds

Sets time format to milliseconds. All position
information is this format after this command.
You can abbreviate milliseconds as ms.

video off
video onEnables or disables video output.

Obtains status information for the device. One of the following items
modifies status:
current track

Returns the current track.

stop

lengthReturns the total length of the segment.

length track
track_number

Returns the length of the serial track specified
by track_number.

number of tracks

Returns the number of tracks on the media.

position

Returns the current position.

position track
track_number

Returns the position of the start of the track
specified by track_number.

start position

Returns the starting position of the media ordevice element.

time format

Returns the time format.

Stops the device.

CD Audio (Redbook) Commands
The CD audio command set provides a common method for playing CD audio sequencesCD audio
devices support the following core set of commands:

Command

Description

capability item

Requests information about the capabilities of the CD audio device.
One of the following items is required:can eject

Returns true if the CD audio device can eject
the media.

can play

Returns true if the CD audio device can play
the media.

can record

Returns false.

can save

Returns false.

compound device

Returns false.

device type

Returns CDaudio.

has audio

Returns true.

has video

Returns false.

uses files

Returns false..

close

Closes the device.

info item

Fills a user-supplied buffer with a NULL-terminated string containing
textual information. One of the following optional item modifies info:
product

open items

Returns the product name and model of thecurrent audio device.

Initializes the device. MCI reserves cdaudio for the compact disc audio
device type. The following optional items modify open:
alias device_ alias

Specifies an alternate name for the given
device. If specified, it must also be used for
subsequent references.

shareable

Initializes the device as shareable. Subsequentattempts to open it fail unless you specify
shareable in both the original and subsequent
open commands. MCI returns an error if it isalready open and not shareable.

pause

Pauses playing.

play items

Starts playing audio. The following optional items modify play:from position toposition

Specifies the position to start and stop
playing.

resumeResumes playing from a paused state.

seek item

Moves to the specified location on the disc. If already playing or
recording, the device is stopped. One of the following items modifies
seek:set items

to position

Specifies the destination position for the seek.
If it is greater than the length of the disc, an
out-of-range error is returned.

to start

Specifies to seek to the start of the audio dataon the CD.

to endSpecifies to seek to the end of the audio dataon the CD.

Sets the various control items:
audio all off
audio all on

Enables or disables audio output..

audio left off
audio left on

Enables or disables output to the left audio
channel.

audio right off
audio right on

Enables or disables output to the right audio
channel.

door closed

Retracts the tray and closes the door if
possible.

door open

Opens the door and ejects the tray if possible.

time format
milliseconds

Sets the time format to milliseconds. All
position information is this format after thiscommand. You can abbreviate milliseconds as
ms.

time format msf

Sets the time format to mm:ss:ff, where mm isminutes, ss is seconds, and ff is frames. All
position information is in this format after thiscommand. On input, ff can be omitted if 0,
and ss can be omitted if both it and ff are 0.
These fields have the following maximum
values:Minutes 99
Seconds 59
Frames 74

time format tmsf

Sets the time format to tt:mm:ss:ff where “ tt”
is tracks, “ mm” is minutes, “ ss” is seconds,
and “ ff” is frames. All position information isin this format after this command. On input“ ff” can be omitted if 0, “ ss” can be omitted
if both it and “ ff” are 0, and “ mm” can beomitted if it, “ ss” and “ ff” are 0. These fields
have the following maximum values:
Tracks 99
Minutes 99
Seconds 59
Frames 74

status item

Obtains status information for the device. One of the following items
modifies status:
current track

Returns the current track.

lengthReturns the total length of the disc.

stop

length track
track_number

Returns the length of the track specified bytrack_number.

media present

Returns true if the CD is inserted in the drive;otherwise, it returns false.

mode

Returns not ready, open, paused, playing,seeking, or stopped for the current mode ofthe drive.

number of tracks

Returns the number of tracks on the CD.

position

Returns the current position.

position track
track_no

Returns the starting position of the track
specified by track_no.

ready

Returns true if the drive is ready.

start position

Returns the starting position of the CD.

time format

Returns the current time format.

Stops playing.

MIDI Sequencer Commands
The MIDI sequencer supports the following set of commands:

Command

Description

capability item

Requests additional information about the capabilities of the MIDI
sequencer. One of the following items is required:can eject

Returns false..

can play

Returns true if the sequencer can play.

can record

Returns true if the sequencer can record MIDI
data.

can save

Returns true if the sequencer can save MIDI
data.

compound device

Generally returns true; most sequencers arecompound devices..

device type

Returns sequencer.

has audio

Returns true.

has video

Returns false.

uses files

Returns true.

close

Closes the sequencer element and the port and file associated with it.

info item

Fills a user-supplied buffer with a NULL-terminated string containing
textual information. One of the following optional item modifies info:
product

open items

Returns the product name of the current MIDI
sequencer.

Initializes the sequencer. The following optional items modify open:
alias device_ alias

Specifies an alternate name for the sequencer
element. If specified, it must also be used for
subsequent references.

shareable

Initializes the sequencer element as shareable.
Subsequent attempts to open it fail unless you
specify shareable in both the original andsubsequent open commands. MCI returns aninvalid device error if it is already open andnot shareable.

type device_ type

MCI reserves sequencer for the MIDI
sequencer device type. As an alternative totype, MCI can use the element filename
extension entries to select the sequencer.

pause

Pauses playing.

play items

Starts playing the sequencer. The following optional items modify
play:from position
to position

Specifies the positions to start and stop
playing. If from is omitted, play starts at thecurrent position; if to is omitted, play stops at
the end of the file.
record items

Starts recording MIDI data. All data recorded after a file is opened is
discarded if the file is closed without saving it. The following optional
items modify record:
insertSpecifies that new data is added to the device
element.

from position
to position

Specifies the positions to start and stop
recording. If from is omitted, the device starts
recording at the current position; if to isomitted, the device records until a stop or
pause command is received.

overwrite

Specifies that new data will replace data in thedevice element.

resumeResumes playing or recording following a pause.

save item

Saves the MCI element. The following item modifies save:
filenameseek item

set items

The filename specifies the destination pathand file.

Moves to the specified position in the file. One of the following items isrequired:
to position

Specifies the final position for the seek.

to start

Specifies to seek to the start of the sequence.

to endSpecifies to seek to the end of the sequence.

Sets the various control items:
audio all off
audio all on

Enables or disables audio output..

audio left off
audio left on

Enables or disables output to the left audio
channel.

audio right off
audio right on

Enables or disables output to the right audio
channel.

master MIDI

Sets the MIDI sequencer as thesynchronization source. Synchronization data
is sent in MIDI format.

master none

Inhibits the sequencer from sending
synchronization data.

master SMPTE

Sets the MIDI sequencer as thesynchronization source. Synchronization data
is sent in SMPTE format.

offset time

Sets the SMPTE offset time in colon form
(hours:minutes:seconds:frames). The offset isthe beginning time of a SMPTE based
sequence.

port port_number

Sets the MIDI port receiving the MIDI
messages. This command will fail if the port
you are trying to open is being used byanother application.

status item

port mapper

Sets the MIDI mapper as the port receiving
the MIDI messages. This command will fail if
the MIDI mapper or a port it needs is being
used by another application.

port none

Disables the sending of MIDI messages..

slave file

Sets the MIDI sequencer to use file data as thesynchronization source. This is the default.

slave MIDI

Sets the MIDI sequencer to use incoming data
MIDI for the synchronization source. The
sequencer recognizes synchronization datawith the MIDI format.

slave none

Sets the MIDI sequencer to ignore
synchronization data.

slave SMPTE

Sets the MIDI sequencer to use incoming
MIDI data for the synchronization source. The
sequencer recognizes synchronization datawith the SMPTE format.

tempo
tempo_value

Sets the tempo of the sequence according to
the current time format. For a ppqn-based file,the integer is interpreted as beats per minute.
For a SMPTE-based file, the integer isinterpreted as frames per second.

time format
milliseconds

Sets time format to milliseconds. All position
information is specified as milliseconds
following this command. The sequence filesets the default format to ppqn or SMPTE.
You can abbreviate milliseconds as ms.

time format song
pointer

Sets time format to song pointer (sixteenth
notes). This can only be performed for asequence of division type ppqn.

time format
SMPTE 24

Sets time format to SMPTE 24 frame rate. All
position information is specified in SMPTE
format following this command. The sequence
file sets the default format to ppqn or SMPTE.

time format
SMPTE 25

Sets time format to SMPTE 25 frame rate. All
position information is specified in SMPTE
format following this command. The sequence
file sets the default format to ppqn or SMPTE.

time format
SMPTE 30

Sets time format to SMPTE 30 frame rate. All
position information is specified in SMPTE
format following this command. The sequence
file sets the default format to ppqn or SMPTE.

time format
SMPTE 30 drop

Sets time format to SMPTE 30 drop frame
rate. All position information is specified in
SMPTE format following this command. The
sequence file sets the default format to ppqn
or SMPTE.

Obtains status information for the MIDI sequencer. One of thefollowing items modifies status:current track

Returns the current track number.

division type

Returns one of the following file division
type: PPQN, SMPTE 24 frame, SMPTE 25
frame, SMPTE 30 drop frame, or SMPTE 30
frame. Use this information to determine theformat of the MIDI file, and the meaning of
tempo and position information.

lengthReturns the length of a sequence in the current
time format. For ppqn files, this will be song
pointer units. For SMPTE files, this will be incolon form (hours:minutes:seconds:frames).

length track
track_number

Returns the length of a sequence using thecurrent time format. For ppqn files, this will
be song pointer units. For SMPTE files, thiswill be in colon form
(hours:minutes:seconds:frames).

masterReturns midi, none, or smpte depending on
the type of synchronization set.

media present

The sequencer returns true.

mode

Returns not ready, paused, playing, seeking,or stopped.

number of tracks

Returns the number of tracks.

offsetReturns the offset of a SMPTE-based file. The
time is returned in colon form
(hours:minutes:seconds:frames). The offset isthe starting time of a SMPTE based sequence.

port

Returns the MIDI port number assigned to thesequence.

position

Returns the current position of a sequence inthe current time format. For ppqn files, thiswill be song pointer units. For SMPTE files,
this will be in colon form
(hours:minutes:seconds:frames).

position track
track_number

Returns the current position of the track
specified by track_number in the current time
format. For ppqn files, this will be song
pointer units. For SMPTE files, this will be incolon form (hours:minutes:seconds:frames).

ready

Returns true if the device is ready.

slave

Returns file, midi, none, or smpte dependingon the type of synchronization set.

start position

Returns the starting position of the media ordevice element.

tempo

Returns the current tempo of a sequence in thecurrent time format. For files with ppqn
format, the tempo is in beats per minute. For
files with SMPTE format, the tempo is inframes per second.

time format
stop

Stops playing.

Returns the time format.

Videodisc Player Commands
Videodisc players support the following core set of commands:

Command

Description

capability item

Reports the capabilities of the device. The device should report
capabilities according to the type of disc (CAV or CLV) inserted in thedrive. If no disc is inserted, the device should assume CAV. One of thefollowing optional items modifies capability:
can eject

Returns true if the device can eject the media.

can play

Returns true if the device supports playing.

can record

Returns true if the video device can record.

can reverse

Returns true if the device can play in reverse,
false otherwise. This is always false if a CLV
disc is inserted.

can save

Returns false.

compound device

Returns false.

device type

Returns videodisc.

fast play rate

Returns the standard fast play rate of theplayer in frames per second. Returns 0 if thedevice cannot play fast.

has audio

Returns true if the videodisc player has audio.

has video

Returns true.

media type

Returns CAV, CLV, or other, depending on
the type of videodisc.

normal play rate

Returns the normal play rate in frames per
second. Returns 0 for CLV discs.

slow play rate

Returns the standard slow play rate in frames
per second. Returns 0 if the device cannot
play slow.

uses files

Returns false.

close

Closes the device.

escape item

Sends custom information to a device. The following item modifies
escape:stringinfo item

Fills a user-supplied buffer with a NULL-terminated string containing
textual information. The following optional item modifies info:
product

open items

Specifies the custom infomation sent to thedevice.

Returns the product name of the device thatthe peripheral is controlling..

Initializes the device. MCI reserves video disc for the videodisc device
type. The following optional items modify open:alias device_ alias

Specifies an alternate name for the given
device. If specified, it must also be used for
subsequent references.

shareable

Initializes the device as shareable. Subsequentattempts to open it fail unless you specify
shareable in both the original and subsequent
open commands. MCI returns an invalid
device error if it is already open and notshareable.

pause

Stops playing. If a CAV disc is playing, it also freezes the video frame.
If a CLV disc is playing, the player is stopped.

play items

Starts playing. The following optional items modify play:
fast
slow

Indicates that the device should play faster orslower than normal. To determine the exact
speed on a particular player, use the status
speed command. To specify the speed more
precisely, use the fps flag. Slow applies only
to CAV discs.

from position
to position

Specifies the positions to start and stop
playing. Positions are in frames for CAV discs
and in seconds for CLV discs, unless chapter
is also used (in which case, the position is
given in chapters). If from is omitted, playstarts at the current position; if to is omitted,
the play stops at the end of the disc.

reverseSets the play direction to backwards. Thisapplies only to CAV discs.

scan

Indicates the play speed is as fast as possible,
possibly with audio disabled. This applies
only to CAV discs.

speed integer

Specifies the rate of play. Currently supported
speed values are measured in frames per
second, which is the default. This applies only
to CAV discs.

resumeResumes playing.

seek item

Searches using fast forward or fast reverse with video and audio off.
The following optional items modify seek:

set items

reverse

Indicates the seek direction on CAV discs isbackwards. This modifier is invalid if to is
specified.

to position

Specifies the end position to stop the seek. If
to is not specified, the seek continues until theend of the media is reached.

to start

Specifies to seek to the start of the disc.

to endSpecifies to seek to the end of the disc.

Sets the various control items:
audio all off
audio all on

Enables or disables audio output.

spin item

status item

audio left off
audio left on

Enables or disables output to the left audio
channel.

audio right off
audio right on

Enables or disables output to the right audio
channel.

door open

Opens the door and ejects the tray, if possible.

door closed

Retracts the tray and closes the door, if
possible.

time format
frames

Sets the position format to frames on CAV
discs. All position information is specified inthis format following this command. This is
the default for CAV discs.

time format hms

Sets position format to h:mm:ss where h ishours, mm is minutes, and ss is seconds. All
position information is specified in this format
following this command. On input, h may beomitted if 0, and mm may be omitted if both it
and h are 0. This is the default for CLV discs.

time format
milliseconds

Sets the position format to milliseconds. All
position information is specified in this format
following this command. You can abbreviate
milliseconds as ms.

time format track

Sets the position format to tracks (chapters).
All position information is specified in thisformat following this command.

video onvideo off

Turns the video on or off.

Starts the disc spinning or stops the disc from spinning. One of thefollowing items modifies status:
down

Stops the disc from spinning.

up

Starts the disc spinning.

Obtains status information for the device. One of the following items
modifies status:
current track

Returns the current track (chapter) number.

disc size

Returns either 8 or 12 to indicate the size ofthe loaded disc in inches.

forwardReturns true if the play direction is forward or
if the device is not playing; false if the play
direction is backward.

lengthReturns the total length of the segment.

length track
track_number

Returns the length of the track (chapter)
specified by track_number.

media present

Returns true if a disc is inserted in the device,false otherwise.

media type

Returns either CAV, CLV, or otherdepending on the type of videodisc.

mode

Returns not ready, opened, paused, parked,

playing, scanning, seeking, or stopped.

step items

stop

number of tracks

Returns the number of tracks (chapters) on the
media.

position

Returns the current position.

position track
track_number

Returns the position of the start of the track(chapter) specified by track_number.

ready

Returns true if the device is ready.

side

Returns 1 or 2 to indicate which side of thedisc is loaded.

speed

Returns the speed in frames per second.

start position

Returns the starting position of the disc.

time format

Returns the time format.

Step the play one or more frames forward or backward. The default
action is to step one frame forward. The step command applies only to
CAV discs. The following items modifies step:by frames

Specifies the number of frames to step. If a
negative value is used, the reverse flag is
ignored.

reverseStep backward.

Stop playing.

Waveform Audio Commands
Waveform audio drivers must support the following core set of commands:

Command

Description

capability item

Requests additional information about the capabilities of the waveform
audio driver. One of the following items modify capability:
can eject

Returns false.

can play

Returns true if the device can play. The wave
audio device returns true if an output device isavailable.

can record

Returns true if the waveform driver canrecord. The waveform audio device returns
true if an input device is available.

can save

Returns true if the wave audio device cansave data.

compound device

Generally returns true; most waveform audio
devices are compound devices.

device type

Returns waveaudio.

has audio

Returns true

has video

Returns false.

inputsReturns the total number of input devices.

outputs

Returns the total number of output devices.

uses files

Returns true.

close

Closes the device element and any resources associated with it.

cue itemPrepares for playing or recording. The cue command does not have to
be issued prior to playing or recording. However, depending on thedevice, it might reduce the delay associated with the play or record
command. This command fails if playing or recording is in progress.
The item is one of the following:

delete items

input

Prepares for recording.

outputPrepares for playing. This is the default.

Deletes a data segment from the MCI element. The following optional
items modify delete:from position
to position

info item

Specifies the positions to start and stop
deleting data. If from is omitted, the deletion
starts at the current position; if to is omitted,
the deletion stops at the end of the file or
waveform.

Fills a user-supplied buffer with a NULL-terminated string containing
textual information. One of the following items modifies info:
file

Returns the current filename.

open items

product

Returns the product name of the current audio
output device.

input

Returns the product name of the current
waveform input device or none if no device isset.

outputReturns the product name of the current
waveform output device or none if no device
is set.

Initializes the device. The following items are optional:
alias device_ alias

Specifies an alternate name for the given
device. If specified, it must also be used thealias for references.

buffer buffer_size

Sets the size in seconds of the buffer used by
the wave audio device. The default size of thebuffer is set when the wave audio device isinstalled or configured. Typically, the buffer
size is set to 4 seconds.

shareable

Initializes the device element as shareable.
Subsequent attempts to open it fail unless you
specify shareable in both the original andsubsequent open commands. MCI returns anerror if it is already open and not shareable.

type device_type

Specifies the compound device used to control
a device element. MCI reserves waveaudio for
the waveform audio device type. As analternative to type, MCI can use the element
filename extension entries to select thecontrolling device

pause

Pauses playing or recording.

play items

Starts playing audio. The following optional items modify play:from position
to position

record items

Specifies the positions to start and stop
playing. If from is omitted, play starts at thecurrent position; if to is omitted, play stops at
the end of the file or waveform.

Starts recording audio. All data recorded after a file is opened is
discarded if the file is closed without saving it. The following optional
items modify record:
insertSpecifies that new data is added to the device
element.

from position
to position

Specifies the positions to start and stop
recording. If from is omitted, the device starts
recording at the current position; if to isomitted, the device records until a stop or
pause command is received.

overwrite

Specifies that new data will replace data in thedevice element.

resumeResumes playing or recording following a pause.

save item

Saves the MCI element in its current format. The following item

modifies save:
filenameseek item

set items

Specifies the file and pathname used to savedata.

Moves to the specified location in the file. Playback or recording is
stopped after the seek. One of the following items modify seek:
to position

Specifies the stop position.

to start

Specifies to seek to the first sample.

to endSpecifies to seek to the last sample.

Sets the following control items:alignment integer

Sets the alignment of data blocks. The file issaved in the new format.

any input

Use any input that supports the current format
when recording. This is the default.

any output

Use any output that supports the current
format when playing. This is the default.

audio all off
audio all on

Enables or disables audio output.

audio left off
audio left on

Enables or disables output to the left audio
channel.

audio right off
audio right on

Enables or disables output to the right audio
channel.

bitspersample
bit_count

Sets the number of bits per sample played orrecorded. The file is saved in this format.

bytespersec
byte_rate

Sets the average number of bytes per second
played or recorded. The file is saved in thisformat.

channelschannel_countSets the channel count for playing andrecording. The file is saved in this format.

format tag tag

Sets the format type for playing and recording.
The file is saved in this format.

format tag pcm

Sets the format type to PCM for playing andrecording. The file is saved in this format.

input integer

Sets the audio channel used as the input.

output integer

Sets the audio channel used as the output.

samplespersec
integer

Sets the sample rate for playing and recording.
The file is saved in this format.

time format bytes

Sets the time format to bytes. All position
information is specified as bytes following
this command.

time format
milliseconds

Sets the time format to milliseconds. All
position information is specified as
milliseconds following this command. You
can abbreviate milliseconds as ms.

time format
samples

Sets the time format to samples. All position
information is specified as samples following

this command.
status item

stop

Obtains status information for the device. One of the following items
modifies status:alignment

Returns the block alignment of data in bytes.

bitspersample

Returns the bits per sample.

bytespersec

Returns the average number of bytes per
second played or recorded.

channels

Returns the number of channels set (1 formono, 2 for stereo).

current track

Returns the index of the current track.

format tag

Returns the format tag.

input

Returns the currently set input. If no input isset, the error returned indicates that any device
can be used.

lengthReturns the total length of the waveform.

length track
track_number

Returns the length of the waveform track.

level

Returns the current audio sample value.

media present

Returns true.

mode

Returns not ready, paused, playing, stopped,
recording, or seeking.

number of tracks

Returns the number of tracks (chapters).

outputReturns the currently set output. If no output
is set, the error returned indicates that any
device can be used.

position

Returns the current position.

position track
track_number

Returns the position of the track specified bytrack_number.

ready

Returns true if the device is ready.

samplespersec

Returns the number of samples per second
played or recorded.

start position

Returns the starting position of the waveform
data.

time format

Returns the current time format.

Stops playing or recording.