Multimedia Group

TEST PLAN

Draft Version 1.14

July, 2006

Contacts:

D. Hands Tel: +44 (0)1473 648184 Email: <david.2.hands@bt.com>

K. Brunnstrom Tel: +46 708 419105 Email: <kjell.brunnstrom@acreo.se>

Editorial History

  ------------- ----------- -------------------------------------------------
  **Version**   **Date**    **Nature of the modification**

  1.0           July 25,    Initial Draft, edited by H. Myler
                2001        

  1.1           28 January, Revised First Draft, edited by David Hands
                2004        

  1.2           19 March,   Text revised following VQEG Boulder 2004 meeting,
                2004        edited by David Hands

  1.3           18 June     Text revised during VQEG meeting, Rome 16-18 June
                2004        2004

  1.4           22October   Text revised during VQEG meeting, Seoul meeting
                2004        October 18-22, 2004

  1.5           18 March    Text revised during MM Ad Hoc Web Meeting, March
                2005        10-18, 2005

  1.5a          22 April    Text revised to include input from GC, IC and CL
                2005        

  1.5b          29 April    Text revised during VQEG meeting, Scottsdale
                2005        25-29 April 2005

  1.5e          30          Text revised during VQEG meeting, Stockholm 26-30
                September   September 2005
                2005        

  1.6           20 November Text updated following audio calls held on 12
                2005        October 2005 and 2 November 2005.

  1.7           29 November Text updated following audio call held on 29
                2005        November 2005.

  1.8           8 December  Text updated following audio call held on 8
                2005        December 2005.

  1.9           22 December Text updated following final call for comments
                2005        (comments to be received by 15 December 2005).

  1.10          25 January  Text updated following comments received during
                2006        review period (comments to be received by 5
                            January 2006).

  1.11          14 February Final core text as agreed by VQEG. Only
                2006        outstanding work is completing all annexes.
                            Current status of the Annexes is as follows.
                            Annexes I, II, VIII and IX are agreed. Annexes
                            IV, VI and VII where tracked changes remain have
                            yet to be agreed. Text still to be provided for
                            Annexes III and V.

  1.12          23 April    Editorial revisions made following audio call of
                2006        2 March 2006.

  1.13          16 June     Text updated following VQEG meeting, Boston,
                2006        April 2006.

  1.14          7 September Test updated following audio call of 7 September
                2006        2006.
  ------------- ----------- -------------------------------------------------

Summary

1.Introduction 6

2.List of Definitions 7

3.List of Acronyms 9

4.Subjective Evaluation Procedure 10

4.1.The ACR Method with Hidden Reference Removal 10

4.1.1.General Description 10

4.1.2.Application across Different Video Formats and Displays 11

4.1.3.Display Specification and Set-up 11

4.1.4.Test Method 12

4.1.5.Subjects 12

4.1.6.Viewing Conditions 13

4.1.7.Experiment design 13

4.1.8.Randomization 14

4.1.9.Test Data Collection 14

4.2.Data Format 15

4.2.1.Results Data Format 15

4.2.2.Subjective Data Analysis 15

5.Test Laboratories and Schedule 17

5.1.Independent Laboratory Group (ILG) 17

5.2.Proponent Laboratories 17

5.3.Test procedure and schedule 17

6.Sequence Processing and Data Formats 21

6.1.Sequence Processing Overview 21

6.1.1.Camera and Source Test Material Requirements 21

6.1.2.Software Tools 21

6.1.3.Colour Space Conversion 22

6.1.4.De-Interlacing 22

6.1.5.Cropping & Rescaling 22

6.1.6.Rescaling 23

6.1.7.File Format 23

6.1.8.Source Test Video Sequence Documentation 24

6.2.Test Materials 24

6.2.1.Selection of Test Material (SRC) 24

6.3.Hypothetical Reference Circuits (HRC) 25

6.3.1.Video Bit-rates 25

6.3.2.Simulated Transmission Errors 25

6.3.4.Live Network Conditions 27

6.3.5.Pausing with Skipping and Pausing without Skipping 28

6.3.6.Frame Rates 28

6.3.7.Pre-Processing 29

6.3.8.Post-Processing 29

6.3.9.Coding Schemes 29

6.3.10.Processing and Editing Sequences 30

7.Objective Quality Models 32

7.1.Model Type 32

7.2.Model Input and Output Data Format 32

7.3.Submission of Executable Model 35

7.4.Registration 35

8.Objective Quality Model Evaluation Criteria 37

8.1.Evaluation Procedure 37

8.2.Data Processing 37

8.2.1.Calculating DMOS Values 37

8.2.2.Mapping to the Subjective Scale 38

8.2.3.Averaging Process 38

8.2.4.Aggregation Procedure 39

8.3.Evaluation Metrics 39

8.3.1.Pearson Correlation Coefficient 39

8.3.2.Root Mean Square Error 39

8.4. Statistical Significance of the Results 41

8.4.1.Significance of the Difference between the Correlation
Coefficients 41

8.4.2.Significance of the Difference between the Root Mean Square Errors
41

8.4.3.Significance of the Difference between the Outlier Ratios 42

9.Recommendation 43

10.Bibliography 44

10.0.1.Introduction 48

10.0.2.Packet switched radio network 48

10.0.3.Wireline Internet 49

10.0.4.Circuit switched radio network 49

10.0.5.Summary of transmission error simulators 49

10.0.6.References 51

10.1.Transformation of source test sequences to UYVY AVI files 59

10.2.AviSynth Scripts for the common transformations 60

10.3.UYVY Raw to UYVY AVI 61

10.4.UYVY Raw to RGB AVI 61

10.5.RGB AVI to UYVY AVI 62

10.6.Processing and Editing Sequences 62

10.7.Calibration 63

10.8.UYVY Decoder to UYVY Raw / UYVY AVI 63

10.9.Notes 64

# Introduction

This document defines the procedure for evaluating the performance of
objective perceptual quality models submitted to the Video Quality
Experts Group (VQEG) formed from experts of ITU-T Study Groups 9 and 12
and ITU-R Study Group 6. It is based on discussions from various
meetings of the VQEG Multimedia working group (MM) recorded in the
Editorial History section at the beginning of this document.

The goal of the MM group is to evaluate perceptual quality models
suitable for digital video quality measurement in multimedia
applications. Multimedia in this context is defined as being of or
relating to an application that can combine text, graphics, full-motion
video, and sound into an integrated package that is digitally
transmitted over a communications channel. Common applications of
multimedia that are appropriate to this study include video
teleconferencing, video on demand and Internet streaming media. The
measurement tools evaluated by the MM group may be used to measure
quality both in laboratory conditions using a FR method and in
operational conditions using RRNR methods.

In the first stage of testing, it is proposed that video only test
conditions will be employed. Subsequent tests will involve audio-video
test sequences, and eventually true multimedia material will be
evaluated. It should be noted that presently there is a lack of both
audio-video and multimedia test material for use in testing. Video
sequences used in VQEG Phase I remain the primary source of freely
available (open source) test material for use in subjective testing. The
VQEG does desire to have copyright free (or at least free for research
purposes) material for testing. The capability of the group to perform
adequate audio-video and multimedia testing is dependent on access to a
bank of potential test sequences.

The performance of objective models will be based on the comparison of
the MOS obtained from controlled subjective tests and the MOSp predicted
by the submitted models. This testplan defines the test method or
methods, selection of test material and conditions, and evaluation
metrics to examine the predictive performance of competing objective
multimedia quality models.

The goal of the testing is to examine the performance of proposed video
quality metrics across representative transmission and display
conditions. To this end, the tests will enable assessment of models for
mobile/PDA and broadband communications services. It is considered that
FR-TV and RRNR-TV VQEG testing will adequately address the higher
quality range (4 Mbit/s and above) delivered to a standard definition
monitor. Thus, the Recommendation(s) resulting from the VQEG MM testing
will be deemed appropriate for services delivered at 4 Mbit/s or less
presented on mobile/PDA and computer desktop monitors.

It is expected that subjective tests will be performed separately for
different display conditions (e.g. one specific test for mobile/PDA;
another test for desktop computer monitor). The performance of submitted
models will be evaluated for each type of display condition. Therefore
it may be possible for one model to be recommended for one display type
(e.g., mobile) and another model for another display format (e.g.,
desktop monitor).

The objective models will be tested using a set of digital video
sequences selected by the VQEG MM group. The test sequences will be
processed through a number of hypothetical reference circuits (HRCs).
The quality predictions of the submitted models will be compared with
subjective ratings from human viewers of the test sequences as defined
by this testplan.

A final report will be produced after the analysis of test results.

# List of Definitions 

[Intended frame rate]{.underline} is defined as the number of video
frames per second physically stored for some representation of a video
sequence. The [intended frame rate]{.underline} may be constant or may
change with time. Two examples of *constant* [intended frame
rates]{.underline} are a BetacamSP tape containing 25 fps and a VQEG
FR-TV Phase I compliant 625-line YUV file containing 25 fps; these both
have an [absolute frame rate]{.underline} of 25 fps. One example of a
*variable* [absolute frame rate]{.underline} is a computer file
containing only new frames; in this case the [intended frame
rate]{.underline} exactly matches the [effective frame
rate]{.underline}. The content of video frames is not considered when
determining [intended frame rate]{.underline}.

[Anomalous frame repetition]{.underline} is defined as an event where
the HRC outputs a single frame repeatedly in response to an unusual or
out of the ordinary event. [Anomalous frame repetition]{.underline}
includes but is not limited to the following types of events: an error
in the transmission channel, a change in the delay through the
transmission channel, limited computer resources impacting the decoder's
performance, and limited computer resources impacting the display of the
video signal.

[Constant frame skipping]{.underline} is defined as an event where the
HRC outputs frames with updated content at an [effective frame
rate]{.underline} that is fixed and less than the [source frame
rate]{.underline}.

[Effective frame rate]{.underline} is defined as the number of unique
frames (i.e., total frames -- repeated frames) per second.

[Frame rate]{.underline} is the number of (progressive) frames displayed
per second (fps).

[Live Network Conditions]{.underline} are defined as errors imposed upon
the digital video bit stream as a result of live network conditions.
Examples of error sources include packet loss due to heavy network
traffic, increased delay due to transmission route changes, multi-path
on a broadcast signal, and fingerprints on a DVD. [Live network
conditions]{.underline} tend to be unpredictable and unrepeatable.

[Pausing with skipping (formerly frame skipping)]{.underline} is defined
as events where the video pauses for some period of time and then
restarts with some loss of video information. In [pausing with
skipping]{.underline}, the temporal delay through the system will vary
about an average system delay, sometimes increasing and sometimes
decreasing. One example of [pausing with skipping]{.underline} is a pair
of IP Videophones, where heavy network traffic causes the IP Videophone
display to freeze briefly; when the IP Videophone display continues,
some content has been lost. Another example is a videoconferencing
system that performs [constant frame skipping]{.underline} or [variable
frame skipping]{.underline}. Constant frame skipping and variable frame
skipping are subsets of pausing with skipping. A processed video
sequence containing [pausing with skipping]{.underline} will be
approximately the same duration as the associated original video
sequence.

P[ausing without skipping (formerly frame freeze)]{.underline} is
defined as any event where the video pauses for some period of time and
then restarts without losing any video information. Hence, the temporal
delay through the system must increase. One example of [pausing without
skipping]{.underline} is a computer simultaneously downloading and
playing an AVI file, where heavy network traffic causes the player to
pause briefly and then continue playing. A processed video sequence
containing [pausing without skipping]{.underline} events will always be
longer in duration than the associated original video sequence.

[Refresh rate]{.underline} is defined as the rate at which the computer
monitor is updated.

[Simulated transmission errors]{.underline} are defined as errors
imposed upon the digital video bit stream in a highly controlled
environment. Examples include simulated packet loss rates and simulated
bit errors. Parameters used to control [simulated transmission
errors]{.underline} are well defined.

[Source frame rate]{.underline} (SFR) is the [intended frame
rate]{.underline} of the original source video sequences. The source
frame rate is constant. For the MM testplan the SFR may be either 25 fps
or 30 fps.

[Transmission errors]{.underline} are defined as any error imposed on
the video transmission. Example types of errors include [simulated
transmission errors]{.underline} and [live network
conditions]{.underline}.

[Variable frame skipping]{.underline} is defined as an event where the
HRC outputs frames with updated content at an [effective frame
rate]{.underline} that changes with time. The temporal delay through the
system will increase and decrease with time, varying about an average
system delay. A processed video sequence containing [variable frame
skipping]{.underline} will be approximately the same duration as the
associated original video sequence.

# List of Acronyms

ACR-HRR Absolute Category Rating with Hidden Reference Removal

ANOVA ANalysis Of VAriance

ASCII ANSI Standard Code for Information Interchange

CCIR Comite Consultatif International des Radiocommunications

CIF Common Intermediate Format (352 x 288 pixels)

CODEC COder-DECoder

CRC Communications Research Centre (Canada)

DVB-C Digital Video Broadcasting-Cable

DMOS Difference Mean Opinion Score

FR Full Reference

GOP Group Of Pictures

HRC Hypothetical Reference Circuit

ILG Independent Laboratory Group

ITU International Telecommunication Union

LSB Least Significant Bit

MM MultiMedia

MOS Mean Opinion Score

MOSp Mean Opinion Score, predicted

MPEG Moving Picture Experts Group

NR No (or Zero) Reference

NTSC National Television Standard Code (60 Hz TV)

PAL Phase Alternating Line standard (50 Hz TV)

PS Program Segment

PVS Processed Video Sequence

QAM Quadrature Amplitude Modulation

QCIF Quarter Common Intermediate Format (176 x 144 pixels)

QPSK Quadrature Phase Shift Keying

VQR Video Quality Rating (as predicted by an objective model)

RR Reduced Reference

SMPTE Society of Motion Picture and Television Engineers

SRC Source Reference Channel or Circuit

VGA Video Graphics Array (640 x 480 pixels)

VQEG Video Quality Experts Group

VTR Video Tape Recorder

# Subjective Evaluation Procedure

## The ACR Method with Hidden Reference Removal

This section describes the test method according to which the VQEG
multimedia (MM) subjective tests will be performed. We will use the
absolute category scale (ACR) \[Rec. P.910\] for collecting subjective
judgments of video samples. ACR is a single-stimulus method in which a
processed video segment is presented alone, without being paired with
its unprocessed ("reference") version. The present test procedure
includes a reference version of each video segment, not as part of a
pair, but as a freestanding stimulus for rating like any other. During
the data analysis the ACR scores will be subtracted from the
corresponding reference scores to obtain a DMOS. This procedure is known
as "hidden reference removal."

### General Description

The selected test methodology is the single stimulus Absolute Category
Rating method with hidden reference removal (henceforth referred to as
ACR-HRR). This choice has been selected due to the fact that ACR
provides a reliable and standardized method (ITU-R Rec. 500-11, ITU-T
P.910) that allows a large number of test conditions to be assessed in
any single test session.

In the ACR test method, each test condition is presented singly for
subjective assessment. The test presentation order is randomized
according to standard procedures (e.g. Latin or Graeco-Latin square, or
via random number generator). The test format is shown in Figure 1. At
the end of each test presentation, human judges (\"subjects\") provide a
quality rating using the ACR rating scale below. Note that the numerical
values attached to each category are only used for data analysis and are
not shown to subjects.

5 Excellent

4 Good

3 Fair

2 Poor

1 Bad

![](media/image1.wmf)

Figure 1 -- ACR basic test cell.

The length of the SRC and PVS should be 8 s.

Instructions to the subjects provide a more detailed description of the
ACR procedure. The instruction script appears in Annex I.

### Application across Different Video Formats and Displays

The proposed MM test will examine the performance of objective
perceptual quality models for different video formats (VGA, CIF and
QCIF). Section 4.1.3 defines format and display types in detail. Video
applications targeted in this test include internet video, mobile video,
video telephony, and streaming video.

Presently, VQEG MM assumes a rolling programme of tests. The audio-video
tests are expected to involve three separate stages. It is expected that
Stage 1 will assess video quality only; the current Test Plan covers
Stage 1. It is expected that Stage 2 will assess audio quality only. It
is expected that Stage 3 will assess overall audio-video quality.

The test instructions request subjects to maintain a specified viewing
distance from the display device. The viewing distance has been agreed
as:

-   QCIF: nominally 6-10 picture heights (H), and let the viewer choose
    within physical limits (natural

> for PDAs).

-   CIF: 6-8H and let the viewer choose within physical limits.

-   VGA: 4-6H and let the viewer choose within physical limits

H=Picture Heights (picture is defined as the size of the video window)

We note regarding the Stage 2 and Stage 3 audio and audio-video tests,
that the room must be acoustically isolated and conform to relevant
international standards (e.g. ITU-T Rec. P.800. and ITU-R Rec. BS.1116).
Use of headphones will be investigated and perhaps included or mandated
in the test (e.g., Stax diffused field equalized Headphones). The
specification and selection of audio cards is to be decided.

### Display Specification and Set-up

Given that the subjective tests will use LCD displays, it is necessary
to ensure that each test laboratory selects appropriate display
specification and common set-up techniques are employed. This Test Plan
requires that LCD displays meet the following specifications:

+----------------------------------+-----------------------------------+
| **Monitor Feature**              | **Specification**                 |
+----------------------------------+-----------------------------------+
| Diagonal Size                    | 17-24 inches                      |
+----------------------------------+-----------------------------------+
| Dot pitch                        | \< 0.30                           |
+----------------------------------+-----------------------------------+
| Resolution                       | Native resolution (no scaling     |
|                                  | allowed)                          |
+----------------------------------+-----------------------------------+
| Gray to Gray Response Time (if   | \< 30 ms                          |
| specified by manufacturer,       |                                   |
| otherwise assume response time   | (\<10 ms if based on white-black) |
| reported is white-black)         |                                   |
+----------------------------------+-----------------------------------+
| Color Temperature                | 6500K                             |
+----------------------------------+-----------------------------------+
| Calibration                      | Yes                               |
+----------------------------------+-----------------------------------+
| Calibration Method               | Eye One / Video Essentials DVD    |
+----------------------------------+-----------------------------------+
| Bit Depth                        | 8 bits/colour                     |
+----------------------------------+-----------------------------------+
| Refresh Rate                     | \>= 60 Hz                         |
+----------------------------------+-----------------------------------+
| Standalone/laptop                | Standalone                        |
+----------------------------------+-----------------------------------+
| Label                            | TCO ´03                           |
+----------------------------------+-----------------------------------+

The LCD shall be set-up using the following procedure:

-   Use the autosetting to set the default values for luminance,
    contrast and colour shade of white.

-   Adjust the brightness according to Rec. ITU-T P.910, but do not
    adjust the contrast (it might change balance of the colour
    temperature).

-   Set the gamma to 2.2.

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-   Set the colour temperature to 6500 K (default value on most LCDs).

The scan rate of the PC monitor must be at least 60 Hz.

The LCD display shall be a high-quality monitor. It is preferred that
all subjective tests use the same LCD monitor panel. This will
facilitate data analysis using data from different tests. Annex V
contains a list of preferred LCD monitors for use in the subjective
tests.

### Test Method

All subjective tests will be run using the same software package. The
software package will include the following components:

-   Entry system for subject details (e.g. name, age, gender)

-   Test screens (prompts to users, grey panel, ACR scale, response
    input, data capture, data storage)

-   Timing control

-   Correct video play-out check

-   Video player

Annex V describes the test method to be used in the VQEG Multimedia
testing. Annex V also provides minimum computer specifications
(including required OS) required when using this subjective test
software package.

### Subjects

Different subjective experiments will be conducted by several test
laboratories. Exactly 24 valid viewers per experiment will be used for
data analysis. A valid viewer means a viewer whose ratings are accepted
after post-experiment results screening. Post-experiment results
screening is necessary to discard viewers who are suspected to have
voted randomly. The rejection criteria verify the level of consistency
of the scores of one viewer according to the mean score of all observers
over the entire experiment. The method for post-experiment results
screening is described in Annex VI. Only scores from valid viewers will
be reported in the results spreadsheets as described in Section 4.2[^1].

The following procedure is suggested to obtain ratings for 24 valid
observers:

1.  Conduct the experiment with 24 viewers

2.  Apply post-experiment screening to eventually discard viewers who
    are suspected to have voted randomly

3.  If n viewers are rejected, run n additional subjects.

4.  Go back to step 2 and step 3 until valid results for 24 viewers are
    obtained

It is preferred that each viewer be given a different randomized order
of video sequences where possible. Otherwise, the viewers will be
assigned to sub-groups, which will see the test sessions in different
randomized orders. A maximum of 4 viewers may be presented with the same
ordering of test sequences per subjective test.

Each viewer can only participate in 1 experiment (i.e. one experiment at
one image resolution).

Only non-expert viewers will participate. The term non-expert is used in
the sense that the viewers' work does not involve video picture quality
and they are not experienced assessors. They must not have participated
in a subjective quality test over a period of six months.

Prior to a session, the observers should usually be screened for normal
visual acuity or corrected-to-normal acuity and for normal color vision.
Acuity will be checked according to the method specified in ITU-T P.910
or ITU-R Rec. 500, which is as follows. Concerning acuity, no errors on
the 20/30 line of a standard eye chart \[I.1\] should be made. The chart
should be scaled for the test viewing distance and the acuity test
performed at the same location where the video images will be viewed
(i.e. lean the eye chart up against the monitor) and have the subjects
seated. Ishihara or Pseudo Isochromatic plates may be used for colour
screening. When using either colour test please refer to usage
guidelines when determining whether subjects have passed (e.g. standard
definition of normal colour vision in the Ishihara test is considered to
be 17 plates correct out of a 38 plate test; ITU-T Rec. P.910 states
that no more than 2 plates may be failed in a 12 plate test.

\[I.1\] Grahm-Field Catalogue Number 13-1240.

### Viewing Conditions

Each test session will involve only one subject per display assessing
the test material. Subjects will be seated directly in line with the
center of the video display at a specified viewing distance (see Section
4.1.2). The test cabinet will conform to ITU-T Rec. P.910 requirements.

### Experiment design

Each subjective experiment will include the same number of 160 PVSs[^2].
The 160 PVSs include both the common set of PVSs inserted in each
experiment and the hidden reference (hidden SRCs) sequences, i.e. each
hidden SRC is one PVS.

The randomization will be applied across the 160 PVSs. The 160 PVSs can
then be split into 2 sessions of 80 PVSs each. In this scenario, an
experiment will include the following steps:

1.  Introduction and instructions to viewer

2.  Practice clips: these test clips allow the viewer to familiarize
    with the assessment procedure and software. They must represent the
    range of distortions in the experiment but with different contents
    than those used in the experiment. A number of 6 practice clips is
    suggested. Ratings given to practice clips are not used for data
    analysis.

3.  Assessment of 80 PVSs

4.  Short break

5.  Practice clips (this step is optional but advised to regain viewer's
    concentration after the break)

6.  Assessment of 80 PVSs

A full matrix approach will be applied for each experiment: each SRC
will be processed through each HRC, i.e. number of PVSs in the
experiment = Nr of SRCs in the experiment x Nr of HRCs in the
experiment.

Each experiment will include a minimum of 6 SRCs and a maximum of 15
SRCs. The SRCS used in each experiment must cover a variety of content
categories as defined in Section 6.2. At least 6 categories of content
must be included in each experiment.

A similar number of PVSs from each type of error will be tested per
image resolution. The image resolutions are defined in Section 4.1.2.
The different types of error conditions are defined in Section 6.1.3.
However different types of error conditions can be mixed between
experiments to ensure a balance in the design of each individual
experiment \[Ed. Note: if one experiment only includes transmission
errors, it will be very difficult to obtain a distribution of MOS across
the entire voting scale\].

### Randomization

For each subjective test, a randomization process will be used to
generate orders of presentation (playlists) of video sequences.
Playlists can be pre-generated offline (e.g. using separate piece of
code or software) or generated by the subjective test software itself.
As stated in section 4.1.4, it is preferred that each subject be given a
different randomized order of video sequences where possible. Otherwise,
the viewers will be assigned to sub-groups, which will see the test
sessions in different randomized orders. A maximum of 4 subjects may be
presented with the same ordering of test sequences per subjective test.

In generating random presentation order playlists the same scene content
may not be presented in two successive trials.

Randomization refers to a random permutation of the set of PVSs used in
that test. Shifting is not permitted, e.g.

Subject1 = \[PVS4 PVS2 PVS1 PVS3\]

Subject2 = \[PVS2 PVS1 PVS3 PVS4\]

Subject3 = \[PVS1 PVS3 PVS4 PVS2\]

...

If a random number generator is used (as stated in section 4.1.1), it is
necessary to use a different starting seed for different tests.

Example script in Matlab that performs playlists (i.e. randomized orders
of presentation) is given below:

rand(\'state\',sum(100\*clock)); % generates a random starting seed

Npvs=200; % number of PVSs in the test

Nsubj=24; % number of subjects in the test

playlists=zeros(Npvs,Nsubj);

for i=1:Nsubj

playlists(:,i)=randperm(Npvs);

end

### Test Data Collection

The responsibity for the collection and organization of the data files
containing the votes will be shared by the ILG Co-Chairs and the
proponents. The collection of data will be supervised by the ILG and
distributed to test participants for verification.

## Data Format

### Results Data Format

The following format is designed to facilitate data analysis of the
subjective data results file.

The subjective data will be stored in a Microsoft Excel spreadsheet
containing the following columns in the following order: lab, test,
type, subject #, month, day, year, session, resolution, rate, age,
gender, order, scene, HRC, ACR Score. Missing data values will be
indicated by the value -9999 to facilitate global search and replacement
of missing values. Each Excel spreadsheet cell will contain either a
number or a name. All names (e.g., test, lab, scene, hrc) must be ASCI
strings containing no white space (e.g., space, tab) and no capital
letters. Where exact text strings are to be used, the text strings will
be identified below in single quotes (e.g., 'original'). Only data from
valid viewers (i.e., viewers who pass the visual acuity and color tests)
will be forwarded to the ILG and other proponents.

Below are definitions for the Excel spreadsheet columns:

[Lab:]{.underline} Name of laboratory's organization (e.g., CRC, Intel,
NTIA, NTT, etc.). This abbreviation must be a single word with no white
space (e.g., space, tab).

[Test:]{.underline} Name of the test. Each test must have a unique name.

[Type:]{.underline} Name of the test category. \[Note: exact text
strings will be specified after individual test categories have been
finalized.\]

[Distance:]{.underline} Viewing distance (e.g. 6to10H, 6to8H, 4to6H).

[Subject #:]{.underline} Integer indicating the subject number. Each
laboratory will start numbering viewers at a different point, to ensure
that all viewers receive unique numbering. Starting points will be
separated by 1000 (e.g., lab1 starts numbering at 1000, lab2 starts
numbering at 2000, etc). Subjects' names will *not* be collected or
recorded.

[Month:]{.underline} Integer indicating month \[1..12\]

[Day:]{.underline} Integer indicating day \[1..31\]

[Year:]{.underline} Integer indicating year \[2004..2006\]

[Session:]{.underline} Integer indicating viewing session

[Resolution:]{.underline} One of the following three strings: 'vga',
'cif' or 'qcif'.

[Rate:]{.underline} A number indicating the frames per second (fps) of
the original video sequence.

[Age:]{.underline} Integer number that indicates the subject's age.

[Gender:]{.underline} 'f' for female, 'm' for male

[Order:]{.underline} An integer indicating the order in which the
subject viewed the video sequences \[or trial number, if scenes are
ordered randomly\].

[Scene:]{.underline} Name of the scene. All scenes from all tests must
have unique names. If a single scene is used in multiple tests (i.e.,
digitally identical files), then the same scene name must be used. Names
shall be eight characters or fewer.

[HRC:]{.underline} Name of the HRC. For reference video sequences, the
exact text 'reference' must be used. All processed HRCs from all tests
must have unique names. If a single HRC is used in multiple tests, then
the same HRC name must be used. HRC names shall be eight characters or
fewer.

[ACR Score:]{.underline} Integer indicating the subject's ACR score (1,
2, 3, 4, or 5).

See Annex II for an example.

### Subjective Data Analysis

Difference scores will be calculated for each processed video sequence
(PVS). A PVS is defined as a SRCxHRC combination. The difference scores,
known as Difference Mean Opinion Scores (DMOS) will be produced for each
PVS by subtracting the score from that of the hidden reference score for
the SRC used to produce the PVS. Subtraction will be done per subject.
Difference scores will be used to assess the performance of each full
reference and reduced reference proponent model, applying the metrics
defined in Section 8.

For evaluation of no-reference proponent models, the absolute (raw)
subjective score will be used. Thus, for each test sequence, only the
absolute rating for the SRC and PVS will be calculated. Based on each
subject's absolute rating for the test presentations, an absolute mean
opinion score will be produced for each test condition. These MOS will
then be used to evaluate the performance of NR proponent models using
the metrics specified in Section 8.

# Test Laboratories and Schedule

Given the scope of the MM testing, both independent test laboratories
and proponent laboratories will be given subjective test
responsibilities. All laboratories will report to VQEG (MMTEST
Reflector) the test environment they plan to use prior to conducting the
subjective test.

## Independent Laboratory Group (ILG)

The independent laboratory group is composed of IRCCyN (France), FUB
(Italy), FT (France), CRC (Canada), INTEL (USA), Acreo (Sweden), and
Verizon (USA).

## Proponent Laboratories

A number of proponents also have significant expertise in and facilities
for subjective quality testing. Proponents indicating a willingness to
participate as test laboratories are BT, Genista, NTIA, NTT, Opticom,
SwissQual, Psytechnics, TDF, Toyama University, KDDI, and Yonsei. It is
clearly important to ensure all test data is derived in accordance with
this testplan. Critically, proponent testing must be free from charges
of advantage to one of their models or disadvantage to competing models.

The maximum number of subjective experiments run by any one proponent
laboratory is 3 times the lowest non-zero number run by any other
proponent laboratory, per image size.

The maximum number of non-secret PVSs included in overall test by any
single proponent laboratory is 20%.

For each proponent subjective test, no more than 20% of test sequences
may be derived from a single proponent.

See Annex IV for details on fees and conditions for proponents
participating in the VQEG Multimedia tests.

## Test procedure and schedule

## 

1.  Approval of test plan \[14 February 2006\]

2.  Declaration of intent to participate and the number of models to
    submit \[6 weeks prior to model submission date\]

3.  VQEG compiles a list of HRCs that are of interest to the MM test.
    Proponents will send details of proposed HRCs and indicate which
    ones they can create to the points of contacts and example PVSs (HRC
    point of contacts Quan Huynh Thu and Philip Corriveau). \[24 March
    2006\]

4.  Each test lab will produce a test design for each subjective test
    they plan to perforom. This test design should be sent to FS and VB
    for initial review to ensure no duplication. \[Draft test designs
    produce by Tokyo meeting; test design for review by 31 October
    2006\] A full and final review of test plans will be performed by
    the ILG and proponent labs. \[30 November 2006\]

5.  Proponents informed by ILG to whom fee payment is made. \[31 May
    2006\]

6.  Content license agreements distributed to proponents and ILG. \[31
    May 2006\]

7.  The proposed lists of HRCs for each experiment are examined by VQEG
    for problems (e.g., one organization creating too many HRCs, overlap
    between experiments, using NTT guidelines). \[9 June 2006\]

8.  Proponents and ILG return completed license agreements to content
    owners. \[15 September 2006\]

9.  ILG send invoice to proponent. \[4 weeks prior to model submission
    date\]

10. All source video sent to content point of contact (Chulhee Lee) \[29
    September 2006\]

11. Source video sent by POC to ILG for de-interlacing. \[to be decided
    in Tokyo 2006\]

12. ILG resize all source video content. \[to be decided in Tokyo 2006\]

13. \*\* Editor's note: if decided not to have ILG de-interlace the
    source content, then the providers of the SRCs must apply
    de-interlaced / resized content along with original source to the
    POC using the tools identified in this testplan. Note that if this
    happens then points 4 and 5 are not applicable.

14. ILG will then select SRC video files and distribute all SRCs to
    regional points of contact (Asia: Chulhee Lee, Europe: Kjell
    Brunnstrom, North America: Filippo Speranza) \[ to be decided in
    Toky 2006\]

15. Participating organizations obtain copies of all SRCs, except for
    the secret SRC. The requesting organization has to pay any costs
    involved. \[to be decided in Tokyo 2006\]

16. Receiving organization must send acknowledgement to MM reflector
    that they have received the SRC files. When all proponents have
    acknowledged to the MM reflector that they have received all SRC
    material, there will be a 3 month period until the submission of
    models. Secret content may still be collected by ILG. Proponents are
    not allowed to provide secret content. \[to be decided in Tokyo
    2006\]

17. Proponents and ILG inform VQEG of any problem source content (e.g.
    artifacts introduced by de-interlacing process). Problem content
    must be made available on ftp site and reviewed by proponents / ILG.
    Majority decision needed to reject suspect source. \[to be decided
    in Tokyo 2006)

18. Fee payment if applicable. Payment will be made directly from each
    proponent to the selected testing facility, according to a table
    agreed on by ILG and distributed to the proponents \[same date as
    model submission\]

19. Proponents submit their models (executable and, only if desired,
    encrypted source code). Procedures for making changes after
    submission will be outlined in a separate document (see Annex VII on
    storing encrypted version of submitted source code). To be approved
    prior to submission of models. \[9 February 2007\]

20. VQEG will agree upon video sequences to be included in
    [every]{.underline} experiment, as proposed by NTT (e.g., 5 SRC & 5
    HRC, which would be 25 of 160 video sequences or 15%). \[2 March
    2007\]

21. ILG select SRC sequences for each experiment and sends them only to
    the organization running that experiment. ILG will send exactly the
    number of SRCs required. \[9 March 2007\]

22. ILG creates a set of secret SRCs and secret HRCs. The ILG inserts
    these into every proponents' experiments. (step 10 + 0.5 month) \[9
    March 2007\]

23. The organization running the experiment will generate the PVSs,
    using the scenes that were sent to them and send all the PVSs to a
    common point of contact. \[13 April 2007\]

24. Proponents check the calibration and registration of the PVSs in
    their experiment. \[20 April 2007\]

25. If a proponent testlab believes that their experiment is unbalanced
    in terms of qualities or have calibration problems, they may ask the
    ILG and the proponent group to review the selection of test
    material. If 2/3^rd^ majority agrees then selection of PVSs will be
    amended by the ILG. An even distribution of qualities from excellent
    to bad is desirable. \[20 April 2007\]

26. All SRCs and PVSs are sent by each test laboratory to a regional
    point of contact. Point of contact then distributes SRCs and PVSs to
    all the proponents \[4 May 2007\]

27. Proponents check calibration of all PVSs and identify potential
    problems. They may ask the ILG to review the selection of test
    material and replace if necessary. \[18 May 2007\]

28. All test material to be used in experiments made available to other
    proponents and ILG for sanity check. If a proponent or ILG does not
    review the test content, then they lose the right to object to the
    content composition of that test. \[18 May 2007\]

29. Each organization runs their test and submits results to the ILG.
    Any source content used in a subjective test with a MOS of \<4 will
    be evaluated by the ILG. The ILG will determine whether the source
    and its associated processed files are valid. Any invalid test
    content will be removed before data analysis is performed and before
    proponents submit their objective data to the ILG. \[27 July 2007\]

30. Proponents run their models and the ILG performs validity checks on
    a subset of test sequences. \[11 August 2007\]

31. Verification of submitted models \[25 August 2007\]

32. ILG distribute subjective and objective data to the proponents and
    other ILG \[25 August 2007\]

33. Statistical analysis \[28 September 2007\]

34. Draft final report \[26 October 2007\]

35. Approval of final report \[16 November 2007\]

36. 

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46. 

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48. 

49. 

50. 

51. 

52. 

53. 

54. 

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56. 

57. 

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66. 

67. 

The ILG will verify that the submitted models (1) run on the ILG's
computers and (2) yield the correct output values when run on the test
video sequences. Due to their limited resources, the ILG may encounter
difficulties verifying executables submitted too close to the model
submission deadline. Therefore, proponents are strongly encouraged to
submit a prototype model to the ILG well before the verification
deadline, to work out platform compatibility problems well ahead of the
final verification date. Proponents are also strongly encouraged to
submit their final model executable 14 days prior to the verification
deadline date, giving the ILG two weeks to resolve problems arising from
the verification procedure.

The ILG requests that proponents kindly estimate the run-speed of their
executables on a test video sequence and to provide this information to
the ILG.

# Sequence Processing and Data Formats

Separate subjective tests will be performed for different video sizes.
One set of tests will present video in QCIF (176x 144 pixels). One set
of tests will present CIF (352x288 pixels) video. One set of tests will
present VGA (640x480). In the case of Rec. 601 video source, aspect
ratio correction will be performed on the video sequences prior to
writing the AVI files (SRC) or processing the PVS.

Note that in all subjective tests 1 pixel of video will be displayed as
1 pixel native display. No upsampling or downsampling of the video is
allowed at the player.

Presently, VQEG has access to a set of video test sequences. For
audio-video tests this database needs to be extended to include new
source material containing both audio and video.

## Sequence Processing Overview

The test material will be selected from a common pool of video
sequences. If the test sequences are in interlace format then a
standard, agreed de-interlacing method will be applied to transform the
video to progressive format. All source material should be 25 or 30
frames per second progressive and there should not be more than one
version of each source sequence for each resolution. The de-interlacing
algorithm will de-interlace Rec. 601 (or other, e.g., HDTV) formatted
video into a progressive format, e.g., VGA, CIF, or QCIF. Algorithms
will be proposed on the VQEG reflector and approved before processing
takes place. Uncompressed AVI files will be used for subjective and
objective tests. Tools are being sought to convert from the various
coding schemes to uncompressed AVI (see Annex VIII for a description of
the tools used for conversion). The progressive test sequences used in
the subjective tests should also be used by the models to produce
objective scores.

It is important to minimize the processing of video source sequences.
Hence, we will endeavor to find methods that minimize this processing
(e.g., to perform de-interlacing and resizing in one step).

### Camera and Source Test Material Requirements

The standard definition source test material should be in Rec. 601,
DigiBeta, Betacam SP, or DV25 (3-chip camera) format or better. Note
that this requirement does not apply to Categories 4 and 8 (Section 6.2)
where the best available quality reference will be used. HD source test
material should be taken from a professional grade HD camera (e.g., Sony
HDR-FX1) or better.  Original HD video sequences that have been
compressed should show no impairments after being re-sampled to VGA,
CIF, and QCIF.

VQEG MM expresses a preference for all test material to be open source.
At a minimum, source material must be available for use within VQEG MM
proponents and ILG for testing (e.g., under non-disclosure agreement if
necessary).

### Software Tools

Transformation of the source test sequences (e.g., from Rec. 601
525-line to CIF) shall be performed using Avisynth 2.5.5, VirtualDub
1.6.11, and ffdshow 20050303. Within VirtualDub, video sequences will be
saved to AVI files using Video Compression option (Video-\>Compressor)
\"ffdshow Video Codec\", configured with the \"Uncompressed\" decoder
and the UYVY color space. For the Colour Depth (Video-\>Color Depth),
the setting "4:2:2 YcbCr (UYVY)" is used as output format. The
processing mode (Video-\>) is set to "Full processing mode".

### Colour Space Conversion

In the absence of known color transformation matrices (e.g., such as
what might be used by a video display adapter), the following algorithms
will be used to transform between ITU-R Recommendation BT.601
Y\'C~B~\'C~R~\' video and R\'G\'B\' video that is in the range
\[0, 255\]. The reference for these color transformation equations is
pages 15-16 of ColorFAQ.pdf, which can be downloaded from:

<http://www.poynton.com/PDFs/ColorFAQ.pdf>

**Transforming R\'G\'B\' to Y\'C~B~\'C~R~\'**

1\. Compute the matrix transformation:

$$\begin{bmatrix}
Y' \\
C_{B}' \\
C_{R}'
\end{bmatrix} = \begin{bmatrix}
\text{16} \\
\text{128} \\
\text{128}
\end{bmatrix} + \frac{1}{\text{256}}\begin{bmatrix}
\text{65}\text{.}\text{738} & \text{129}\text{.}\text{057} & \text{25}\text{.}\text{064} \\
 - \text{37}\text{.}\text{945} & - \text{74}\text{.}\text{494} & \text{112}\text{.}\text{439} \\
\text{112}\text{.}\text{439} & - \text{94}\text{.}\text{154} & - \text{18}\text{.}\text{285}
\end{bmatrix} \cdot \begin{bmatrix}
R' \\
G' \\
B'
\end{bmatrix}$$

2\. Round to the nearest integer.

3\. Clamp all three components to the range 1 through 254 inclusive (0
and 255 are reserved for synchronization signals in ITU-R Recommendation
BT.601).

**Transforming Y\'C~B~\'C~R~\' to R\'G\'B\'**

1\. Compute the matrix transformation:

$$\begin{bmatrix}
R' \\
G' \\
B'
\end{bmatrix} = \frac{1}{\text{256}}\begin{bmatrix}
\text{298}\text{.}\text{082} & 0 & \text{408}\text{.}\text{583} \\
\text{298}\text{.}\text{082} & - \text{100}\text{.}\text{291} & - \text{208}\text{.}\text{120} \\
\text{298}\text{.}\text{082} & \text{516}\text{.}\text{411} & 0
\end{bmatrix} \cdot \left( \begin{bmatrix}
Y' \\
C_{B}' \\
C_{R}'
\end{bmatrix} - \begin{bmatrix}
\text{16} \\
\text{128} \\
\text{128}
\end{bmatrix} \right)$$

2\. Round to the nearest integer.

3\. Clamp all three components to the range 0 through 255 inclusive.

### De-Interlacing

De-interlacing will be performed when original material is interlaced,
using the de-interlacing function "KernelDeint" in Avisynth. If the
deinterlacing using KernelDeint results in source sequence that has
serious artifacts, the Blendfield or Autodeint may be used as
alternative methods for deinterlacing.

### Cropping & Rescaling

Table 2 lists recommend values for region of interests to be used for
transforming images. These source regions should be centered vertically
and horizontally. These source regions are intended to be applied
*prior* to rescaling and avoid use of over scan video in most cases.
These regions are known to correctly produce square pixels in the target
video sequence. Other regions may be used, provided that the target
video sequence contains the correct aspect ratio.

TABLE 2. Recommended Source Regions for Video Transformation

  -------------------------- --------------------------- -----------------
  **From**                   **To**                      **Source Region**

  525-line: 720x486 Rec. 601 VGA: 640x480 square pixel   704x480

  525-line: 720x486 Rec. 601 CIF: 352x288 square pixel   646x480

  525-line: 720x486 Rec. 601 QCIF: 176x144 square pixel  646x480

  625-line: 720x576 Rec. 601 VGA: 640x480 square pixel   702x576

  625-line: 720x576 Rec. 601 CIF: 352x288 square pixel   644x576

  625-line: 720x576 Rec. 601 QCIF: 176x144 square pixel  644x576

  1080i: 1920x1080           VGA: 640x480 square pixel   1440x1080

  1080i: 1920x1080           CIF: 352x288 square pixel   1320x1080

  1080i: 1920x1080           QCIF: 176x144 square pixel  1320x1080

  720p: 1280x720             VGA: 640x480 square pixel   960x720

  720p: 1280x720             CIF: 352x288 square pixel   880x720

  720p: 1280x720             QCIF: 176x144 square pixel  880x720
  -------------------------- --------------------------- -----------------

### Rescaling

Video sequences will be resized using Avisynth's 'LanczosResize'
function.

### File Format

All source and processed video sequences will be stored in Uncompressed
AVI in UyVy..

Source material with a source frame rate of 29.97 fps will be manually
assigned a source frame rate of 30 fps prior to being inserted into the
common pool of video sequences.

AVI is essentially a container format that consists of hierarchical
chunks -- which have their equivalent in C data structures -- which are
all preceded by a so called fourcc, a "four character code", which
indicates the type of chunk following. Some of the chunks are compulsory
and describe the structure of the file, while some are optional and
others contain the real video or audio data. The AVI container format
which is used for the exchange of files in VQEG MM is originally defined
by Microsoft as part of the RIFF file specification in:

"<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wcedshow/html/_dxce_dshow_avi_riff_file_reference.asp>"

Other descriptions can be found in:

<http://www.opennet.ru/docs/formats/avi.txt>

<http://www.the-labs.com/Video/odmlff2-avidef.pdf>

These last two can be found on the mmpretest ftp server. All these links
describe the AVI format in details as far as the container itself is
concerned. Since the multitude of chunks is quite confusing, an example
C code that reads and writes AVI files down to this level is also
included in the archive on the mmpretest reflector (files avilib.c and
avilib.h). Please note, that the provided C code falls under the GNU
Public License. Please refer to the license statements in the files
themselves. The provided C code is very simple to use and should serve
all needs of VQEG. Please note that the C code allows opening the data
chunk with the UVVY data, but it does not decode this data. In fact,
avilib does not know how to interpret these data. All it returns is a
pointer to the data and some additional information like image sizes and
frame rate. Interpretation of these data is up to the user and described
in the following paragraphs.

A description of the UYVY chunk format which is to be used inside the
AVI container can be found in
<http://www.fourcc.org/index.php?http%3A//www.fourcc.org/fccyvrgb.php>
and below.

UYVY is a YUV 4:2:2 format. The effective bits per pixel are 16. In the
AVI main header (after the fourcc "avih"), a positive height parameter
implies a top-down image (top line first).Two image pixels form one
macro pixel and are stored in one 32bit word with the following byte
ordering:

(lowest byte) U~0~ Y~0~ V~0~ Y~1~ (highest byte)

### Source Test Video Sequence Documentation

Preferably, each source video sequence should be documented. The exact
process used to create each source video sequence should be documented,
listing the following information:

-   Camera specifications

-   Source region of interest (if the default values were not used)

-   Use restrictions (e.g., "open source")

-   Deinterlacing method

This documentation is desirable but not required.

## Test Materials

The test material will be representative of a range of content and
applications. The list below identifies the type of test material that
forms the basis for selection of sequences.

1\) video conferencing: (available for research purposes only, NTIA (Rec
601 60Hz); BT (Rec 601 50Hz), Yonsei (CIF and QCIF), FT (Rec 601 50Hz,
D1)), NTT (Rec 601 60Hz, D1)

2\) movies, movie trailers:(VQEG Phase II), Opticom (trailer equivalent,
restricted within VQEG)

3\) sports: (available, 15-20 mins from Yonsei, Comcast), KDDI (7 min D1
and D2, other scenes also available), NTIA (Comcast)

4\) music video: (Intel)

5\) advertisement:

6\) animation: (graphics Phase I, cartoon Phase II; Opticom will send
material to Yonsei)

7\) broadcasting news: (head and shoulders and outside broadcasting).
(available -- Yonsei;, possible Comcast)

8\) home video: (FUB possibly, BT possibly, INTEL, NTIA). Must be
captured with DV camera or better.

All test material should be sent to the content point of contact
(Chulhee Lee, Yonsei) first and then it will be put on the ftp server by
NTIA. Ideally the material should be converted before being sent to
Chulhee Lee.

The source video will only be used in the testing if an expert in the
field considers the quality to be good or excellent on an ACR-scale.

### Selection of Test Material (SRC)

The ILG is responsible for selecting SRC material to be used in each
subjective quality test. The VQEG MM group will be responsible for
deciding upon precise HRCs to be used in the testing. Section 5.3
provides basic guidelines on the process for selecting SRCs and HRCs
together with a procedure for the distribution of test content.

## Hypothetical Reference Circuits (HRC)

The subjective tests will be performed to investigate a range of HRC
error conditions. These error conditions may include, but will not be
limited to, the following:

-   Compression errors (such as those introduced by varying bit-rate,
    codec type, frame rate and so on)

-   Transmission errors

-   Post-processing effects

-   Live network conditions

-   Interlacing problems

The overall selection of the HRCs will be done such that most, but not
necessarily all, of the following conditions are represented.

### Video Bit-rates

-   PDA/Mobile (QCIF): 16 kbit/s to 320 kbs (e.g., 16, 32, 64, 128, 192,
    320)

-   PC1 (CIF): 64 kbit/s to 704 kbit/s (e.g. 64, 128, 192, 320, 448,
    704)

-   PC2 (VGA): 128kbit/s to 4Mbit/s (e.g. 128, 256, 320, 448, 704, \~1M,
    \~1.5M, \~2M, 3M,\~4M)

### Simulated Transmission Errors

A set of test conditions (HRC) will include error profiles and levels
representative of video transmission over different types of transport
bearers:

-   Packet-switched transport (e.g., 2G or 3G mobile video streaming,
    PC-based wireline video streaming)

-   Circuit-switched transport (e.g., mobile video-telephony)

It is important that when creating HRCs using a simulator, documentation
is produced detailing simulator settings (for circuit switched HRCs the
error pattern for each PVS should also be produced).

Annex III provides guidelines on the procedures for creating and
documenting transmission error conditions.

**Packet-switched transmission**

HRCs will include packet loss with a range of packet loss ratios (PLR)
representative of typical real-life scenarios.

In **mobile video streaming**, we consider the following scenarios:

1.  Arrival of packets is delayed due to re-transmission over the air.
    Re-transmission is requested either because packets are corrupted
    when being transmitted over the air, or because of network
    congestion on the fixed IP part. Video will play until the buffer
    empties if no new (error-checked/corrected) packet is received. If
    the video buffer empties, the video will pause until a sufficient
    number of packets is buffered again. This means that in the case of
    heavy network congestion or bad radio conditions, video will pause
    without skipping during re-buffering, and no video frames will be
    lost. This case is not implemented in the current test plan as
    stated in Section 6.3.4.

2.  Arrival of packets is delayed, and the delay is too large: These
    packets are discarded by the video client.

> Note: A radio link normally has *in-order delivery*, which means that
> if one packet is delayed the following packets will also be delayed.
>
> Note: If the packet delay is too long, the radio network might drop
> the packet.

3.  Very bad radio conditions: Massive packet loss occurs.

4.  Handovers: Packet loss can be caused by handovers. Packets are lost
    in bursts and cause image artifacts.

> Note: This is valid only for certain radio networks and radio links,
> like GSM or HSDPA in WCDMA. A dedicated radio channel in WCDMA uses
> soft handover, which not will cause any packet loss.

Typical radio network error conditions are:

-   Packet delays between 100 ms and 5 seconds.

In **PC-based wireline video streaming**, network congestion causes
packet loss during IP transmission.

In order to cover different scenarios, we consider the following models
of packet loss:

-   Bursty packet loss. The packet loss pattern can be generated by a
    link simulator or by a bit or block error model, such as the
    Gilbert-Elliott model.

-   Random packet loss

-   Periodic packet loss.

Note: The bursty loss model is probably the most common scenario in a
'normal' network operation. However, periodic or random packet loss can
be caused by a faulty piece of equipment in the network. Bursty, random,
and periodic packet loss models are available in commercially-available
packet network emulators.

Choice of a specific PLR is not sufficient to characterize packet loss
effects, as perceived quality will also be dependent on codecs, content,
packet loss distribution (profiles) and which types of video frames were
hit by the loss of packets. For our tests, we will select different
levels of loss ratio with different distribution profiles in order to
produce test material that spreads over a wide range of video quality.
To confirm that test files do cover a wide range of quality, the
generated test files (i.e., decoded video after simulation of
transmission error) will be:

1.  Viewed by video experts to ensure that the visual degradations
    resulting from the simulated transmission error spread over a range
    of video quality over different content;

2.  Checked to ensure that degradations remain within the limits stated
    by the test plan (e.g., in the case where packet loss causes loss of
    complete frames, we will check that temporal misalignment remains
    with the limits stated by the test plan).

**Circuit-switched transmission**

HRCs will include bit errors and/or block errors with a range of bit
error rates (BER) or/and block[^3] error rates (BLER) representative of
typical real-world scenarios. In circuit-switched transmission, e.g.,
video-telephony, no re-transmission is used. Bit or block errors occur
in bursts.

In order to cover different scenarios, the following error levels can be
considered:

Air interface block error rates: Normal uplink and downlink: 0.3%,
normally not lower. High value uplink: 0.5%, high downlink: 1.0%. To
make sure the proponents' algorithms will handle really bad conditions
up to 2%-3% block errors on the downlink can be used.

Bit stream errors: Block errors over the air will cause bits to not be
received correctly over the air. A video telephony (H.223) bit stream
will experience CRC errors and chunks of the bit stream will be lost.

Tools are currently being sought to simulate the types of error
transmission described in this section.

Proponents are asked to provide examples of level of error conditions
and profiles that are relevant to the industry. These examples will be
viewed and/or examined after electronic distribution (only open source
video is allowed for this).

###  {#section-1 .unnumbered}

### Live Network Conditions

Simulated errors are an excellent means to test the behavior of a system
under well defined conditions and to observe the effects of isolated
distortions. In real live networks however usually a multitude of
effects happen simultaneously when signals are transmitted, especially
when radio interfaces are involved. Some effects like e.g. handovers,
can only be observed in live networks.

The term \"live network\" specifies conditions which make use of a real
network for the signal transmission. This network is not exclusively
used by the test setup. It does not mean that the recorded data
themselves are taken from live traffic in the sense of passive network
monitoring. The recordings may be generated by traditional intrusive
test tools, but the network itself must not be simulated.

Live network conditions of interest include radio transmission (e.g.,
mobile applications) and fixed IP transmission (e.g., PC-based video
streaming, PC to PC video-conferencing, best-effort IP-network with
ADSL-access). Live network testing conditions are of particular value
for conditions that cannot confidently be generated by network simulated
transmission errors (see section 6.3.4). Live network conditions should
exhibit distortions representative of real-world situations that remain
within the limits stated elsewhere in this test plan.

Normally most live network samples are of very good or best quality. To
get a good proportion of sample quality levels, an even distribution of
samples from high to low quality should be saved after a live network
session.

Note: Keep in mind the characteristics of the radio network used in the
test. Some networks will be able to keep a very good radio link quality
until it suddenly drops. Other will make the quality to slowly degrade.

Samples with perfect quality do not need to be taken from live network
conditions. They can instead be recorded from simulation tests.

Live network conditions as opposed to simulated errors are typically
very uncontrolled by their nature. The distortion types that may appear
are generally very unpredictable. However, they represent the most
realistic conditions as observed by users of e.g. 3G networks.

Recording PVSs under live network conditions is generally a challenging
task since a real hardware test setup is required. Ideally, the capture
method should not introduce any further degradation. The only
requirement on capture method is that the captured sequences conform to
the file requirements in section 6.1.7 and 7.2.

For applications including radio transmissions, one possibility is to
use a laptop with e.g. a built-in 3G network card and to download
streams from a server through a radio network. Another possibility is
the use of drive test tools and to simulate a video phone call while the
car is driving. In order to simulate very bad radio coverage, the
antenna may be wrapped with some aluminum foil (Editors note: This
strictly a simulation again, but for the sake of simplicity it can be
accepted since the simulated bad coverage is overlayed with the effects
from the live network).

In order to prepare the PVSs the same rules apply as for simulated
network conditions. The only difference is the network used for the
transmission.

### Pausing with Skipping and Pausing without Skipping

Pausing without skipping events will not be included in the current
testing.

Pausing with skipping events will be included in the current testing.
Anomalous frame repetition is not allowed during the first 1s or the
final 1s of a video sequence. Note that where pausing with skipping and
anomalous frame repetition is included in a test then source material
containing still sections should form part of the testing.

If it is difficult or impossible to determine whether a video sequence
contains pausing without skipping or pausing with skipping, the video
sequence will be given the benefit of doubt and considered to contain
pausing with skipping. The same applies to anomalous frame repetition in
the first 1s or final 1s of video sequence.

Other types of anomalous behavior are allowed provided they meet the
following restrictions. The delay through the system before, after, and
between anomalous behavior segments must vary around an average delay
and must meet the temporal registration limits in section 7.4. The first
1s and final 1s of each video sequence cannot contain any anomalous
behavior. At most 25% of any individual PVS\'s duration may exceed the
temporal registration limits in section 7.4. These 25% must have a
maximum temporal registration error of +3 seconds (added delay).

(See section 2 for definitions of "pausing with skipping", "pausing
without skipping" and "anomalous frame repetition".)

### Frame Rates

For those codecs that only offer automatically set frame rate, this rate
will be decided by the codec. Some codecs will have options to set the
frame rate either automatically or manually. For those codecs that have
options for manually setting the frame rate (and we choose to set it for
the particular case), 5 fps will be considered the minimum frame rate
for VGA and CIF, and 2.5 fps for PDA/Mobile..

Manually set frame rates (constant frame rate) may include:

-   PDA/Mobile: 30, 25, 15, 12.5, 10, 8, 5, 2.5 fps

-   PC1 (CIF): 30, 25, 15, 12.5, 10, 8, 5 fps

-   PC2 (VGA): 30, 25, 15, 12.5, 10,8, 5 fps

Variable frame rates are acceptable for the HRCs. The first 1s and last
1s of each QCIF PVS must contain at least two unique frames, provided
the source content is not still for those two seconds. The first 1s and
last 1s of each CIF and VGA PVS must contain at least four unique
frames, provided the source content is not still for those two seconds.

Care must be taken when creating test sequences for display on a PC
monitor. The refresh rate can influence the reproduction quality of the
video and VQEG MM requires that the sampling rate and display output
rate are compatible. For example,

Given a source frame rate of video is 30fps, the sampling rate is 30/X
(e.g. 30/2 = sampling rate of 15fps). This is called frame rate. Then we
upsample and repeat frames from the sampling rate of 15fps to obtain 30
fps for display output.

The intended frame rate of the source and the PVS must be identical.

### Pre-Processing

The HRC processing may include, typically prior to the encoding, one or
more of the following:

-   Filtering

-   Simulation of non-ideal cameras (e.g. mobile)

-   Colour space conversion (e.g. from 4:2:2 to 4:2:0)

This processing will be considered part of the HRC.

### Post-Processing

The following post-processing effects may be used in the preparation of
test material:

-   Colour space conversion

-   De-blocking

-   Decoder jitter

### Coding Schemes

Coding Schemes that will be used may include, but are not limited to:

-   Windows Media Player 9

-   H.263

-   H.264 (MPEG-4 Part 10)

-   Real Video (e.g. RV 10)

-   MPEG 4

### Processing and Editing Sequences

Test sequences will be captured from the decoded video in uncompressed
format. The two capture methods below have been identified, but others
may be used as well. Strict documentation of how PVSs have been produced
should be forwarded to the ILG.

**SwissQual method**

Video capture is done using proprietary software developed at SwissQual.
The software captures an uncompressed video signal directly from
QuickTime player v7.0 generating two files. The first file contains
video data in AVI format whereas a second file contains a list of the
time-stamps of the received frames. The input signal can also contain a
variable frame rate.

QuickTime 7.0 supports most known video encoding formats like: MPEG-4,
H.261, H.263, H.264, Cinepak, DV-PAL/NTSC, Intel Indeo etc.

Recording at variable frame rate reduces the amount of redundancy in
video frames during pausing without skipping events. There are two
possibilities to play back the PVS on the display:

-   Using a proprietary Player (SQAviPlayer), which reads AVI file at
    variable frame rate and time stamps from LOG file.

-   Using a standard player e.g. QuickTime connected to an output of
    SQVRtoCR

SQVRtoCR converts variable to constant frame rate PVSs.

![](media/image2.png){width="1.0188976377952756in"
height="0.6326771653543307in"}

**NTT method** PIFREC 1.0 (Lossless PC Video & Voice Recorder)

The PC capture system uses a capture board to receive the signals passed
from a PC to its monitor, without adding any processing load to the PC,
and stores them while retaining high video quality. So, video service
providers can evaluate and monitor video quality, an operation which is
particularly necessary if the video service is charged for, without
imposing a processing load on the receiving terminal, a penalty which
has conventionally been unavoidable.

![](media/image3.wmf){width="6.129861111111111in" height="2.89375in"}

Product composition:

+----------------------------------+-----------------------------------+
| PC video & voice recording       | Frame detection, and storing of   |
| software                         | video and voice data              |
+----------------------------------+-----------------------------------+
| PC video capture board           | High-resolution video capture     |
+----------------------------------+-----------------------------------+
| Video capturing PC set           | Video play-back                   |
|                                  |                                   |
| (PC, hard disc and other         |                                   |
| peripherals. Monitor is not      |                                   |
| included)                        |                                   |
+----------------------------------+-----------------------------------+

Specification:

  ----------------------------------- -----------------------------------
  Input format                        Analog signal/digital signal (DVI)

  Output format                       AVI format Video: uncompressed
                                      video, reference video Voice:
                                      uncompressed audio

  Maximum recording time              1 hour (in the case of VGA and
                                      30fps)

  Recording performance               VGA, 30fps\* and full color (24
                                      bits)
  ----------------------------------- -----------------------------------

\*Frame rate: the number of frames displayed on the monitor each second.
30fps for example means that the display is refreshed 30 times each
second. The higher the value, the smoother the video looks. The frame
rate of television (NTSC) is 30fps.

# Objective Quality Models

## Model Type

VQEG MM has agreed that Full Reference, Reduced Reference and No
Reference models may be submitted for evaluation. The side-channels
allowable for the RR models are:

-   PDA/Mobile (QCIF): (1kbit/s, 10kbit/s)

-   PC1 (CIF): (10kbit/s, 64kbit/s)

-   PC2 (VGA): (10kbit/s, 64kbit/s, 128kbit/s)

Note that for each side-channel condition the limits defined here
represent the maximum allowable side-channel data rate. For example,
where the side-channel is limited to 10 kbit/s, then valid side-channels
are those that use a data rate of \<=10 kbit/s and any data rates above
10 kbit/s are invalid.

Proponents may submit one model of each type for all image size
conditions. Thus, any single proponent may submit up to a total of 13
different models (one FR model for QCIF, one FR model for CIF, one FR
model for VGA; one NR model for QCIF, one NR model for CIF, one NR model
for VGA; two RR models for QCIF, two RR models for CIF, three RR models
for VGA). Note that where multiple models are submitted, additional
model submission fees may apply.

## Model Input and Output Data Format

Video will be full frame, full frame rate. The progressive video format
will be used in the multimedia test.

7.2.1 Full reference Models

The FR model will be given an ASCII file listing pairs of video sequence
files to be processed. Each line of this file has the following format:

\<source-file\> \<processed-file\>

where \<source-file\> is the name of a source video sequence file and
\<processed-file\> is the name of a processed video sequence file, whose
format is specified in section 6.1.7 of this document. File names may
include a path. For example, an input file should adhere to the
following naming convention:

**/video/vXX_YYY.avi /video/vXX_YYY.avi**

**/video/cXX_YYY.avi /video/cXX_YYY.avi**

**/video/qXX_YYY.avi /video/qXX_YYY.avi**

where v represents VGA, c represents CIF, q represents QCIF, XX
indicates the test number and YYY represents the video sequence index.
The leading characters (v,c,q) and all extensions ("avi" and "dat")
should be in lower cases.

The output file is an ASCII file created by the model program, listing
the name of each processed sequence and the resulting Video Quality
Rating (VQR) of the model. The contents of the output file should be
flushed after each sequence is processed, to allow the testing
laboratories the option of halting a processing run at any time. Each
line of the ASCII output file has the following format:

\<processed-file\> VQR

Where \<processed-file\> is the name of the processed sequence run
through this model, without any path information. VQR is the Video
Quality Ratings produced by the objective model. For the input file
example, this file contains the following:

**v01_001.avi 0.150**

**v01_002.avi 1.304**

**v01_003.avi 0.102**

**v01_004.avi 2.989**

Each proponent is also allowed to output a file containing Model Output
Values (MOVs) that the proponents consider to be important. The format
of this file will be

**v01_001.avi 0.150 MOV~1~ MOV~2~,... MOV~N~**

**v01_002.avi 1.304 MOV~1~ MOV~2~,... MOV~N~**

**v01_003.avi 0.102 MOV~1~ MOV~2~,... MOV~N~**

**v01_004.avi 2.989 MOV~1~ MOV~2~,... MOV~N~**

7.2.2 Reduced-reference Models

In an effort to limit the amount of variations and in agreement with all
proponents attending the VQEG meeting consensus was achieved to allow
only downstream video quality models.

7.2.2.1 Downstream Model Original Video Processing:

The software (model) for the original video side will be given the
original test sequence in the final file format and produce a reference
data file. The amount of reference information in this data file will be
evaluated in order to estimate the bit rate of the reference data and
consequently assign the class of the method (Section 7.1). The input
file format of the full-reference model will be used for the RR model
for the original video side. Deterministic RR models for the original
video side may ignore the processed video file name which is the second
argument. For example, given an input file:

**/video/qXX_YYY.avi /video/qXX_ZZZ.avi**

Then, the model should produce reference data files whose file names are
made in the following way:

**/video/qXX_YYY_BBB.dat (deterministic models) or**

**/video/qXX_YYY_ZZZ_BBB.dat (deterministic and non-deterministic
models)**

where BBB indicates side-channel bandwidth in kbps. For example, for a
VGA RR model with the 10kbps side channel, the output file names should
be as follows:

**vXX_001_10.dat**

**vXX_002_10.dat**

**or**

**vXX_001_023_10.dat**

**vXX_002_100_10.dat.**

The model should save the output files in the current directory. The ILG
should make sure that PVS files are not available for the software for
the original video side.

7.2.2.2 Downstream Model Processed Video Processing:

The software (model) for the processed video side will be given the
processed test sequence in the final file format and a reference data
file that contains the reduced-reference information (see Model Original
Video Processing). The input file format of the full-reference model
will be used for the model for the processed video side. The format of
this file will be

**/video/qXX_YYY.avi /video/qXX_ZZZ.avi**

where v indicates VGA resolution, XX indicates the test number, YYY
represents the source video sequence index and ZZZ represents the
processed video sequence index. Then, the model should make reference
data file names as follows:

/video/qXX_YYY_BBB.dat (deterministic models) OR

/video/qXX_YYY_ZZZ_BBB.dat (deterministic and non-deterministic models)

where BBB indicates side-channel bandwidth in kbps. Finally, the model
should use the processed video file and the reference data file, and
produce a VQR for the processed video sequence. The ILG should make sure
that SRC files are not available for the software for the processed
video side.

The output file format of the RR model will be identical with that of
the FR model (Section 7.2.1).

7.2.2.3 Input Parameters for RR models.

Some RR models, the identical software may generate and process
reference data files at various side-channel bandwidths. In this case,
the software needs information on side-channel bandwidth. In order to
provide the information, the software (model) for the original video
side will be given two arguments as follows:

**CompanyName_vRRsrc.exe vXX.txt BBB**

where vXX.txt is the input file name, XX indicates the test number and
BBB indicates side-channel bandwidth in kbps.

The software (model) for the processed video side will be given two
arguments as follows:

**CompanyName_vRRpvs.exe vXX.txt BBB**

7.2.3 No-reference Models

The NR model will be given a ASCII file listing only processed video
sequence files. Each line of this file has the following format:

\<processed-file\>

where \<processed-file\> is the name of a processed video sequence file,
whose format is specified in section 6.1.7 of this document. File names
may include a path. For example, an input file should adhere to the
following naming convention:

**/video/vXX_001.avi**

**/video/vXX_002.avi**

The output file format of the NR model will be identical with that of
the FR model (Section 7.2.1).

NR models will be required to predict the perceptual quality of both the
source and processed video files used in subjective quality tests.

## Submission of Executable Model

For each video format (QCIF, CIF, and VGA), a set of 2 source and
processed video sequence pairs will be used as test vectors. They will
be available for downloading on the VQEG web site
<http://www.vqeg.org/>.

Each proponent will send an executable of the model and the test vector
outputs to the ILG by the date specified in action item "Proponents
submit their models (executable and, only if desired, encrypted source
code)" of Section 5.3. The executable version of the model must run
correctly on one of the two following computing environments:

-   SUN SPARC workstation running the Solaris 2.3 UNIX operating system
    (SUN OS 5.5). \[Ed. Note: The used of SUN workstation should be
    agreed\]

-   WINDOWS 2000 workstation and Windows XP.

The use of other platforms will have to be agreed upon with the
independent laboratories prior to the submission of the model.

The ILG will verify that the software produces the same results as the
proponent with a maximum error of plus or minus 0.0001% of the
proponents reported value. See Annex X for requirements on
non-deterministic models. A maximum of 5 randomly selected files will be
used for verification. If greater errors are found, the independent and
proponent laboratories will work together to correct them. If the errors
cannot be corrected, then the ILG will review the results and recommend
further action.

## Registration

Measurements will only be performed on the portions of PVSs that are not
anomalously severely distorted (e.g. in the case of transmission errors
or codec errors due to malfunction).

Models must include calibration and registration if required to handle
the following technical criteria (Note: Deviation and shifts are defined
as between a source sequence and its associated PVSs. Measurements of
gain and offset will be made on the first and last seconds of the
sequences. If the first and last seconds are anomalously severely
distorted, then another 2 second portion of the sequence will be used.):

-   maximum allowable deviation in *offset* is ±20

-   maximum allowable deviation in *gain* is ±0.1

-   maximum allowable *Horizontal Shift* is +/- 1 pixel

-   maximum allowable *Vertical Shift* is +/- 1 pixel

-   maximum allowable *Horizontal Cropping* is 12 pixels for VGA, 6
    pixels for CIF, and 3 pixels for QCIF (for each side).

-   maximum allowable *Vertical Cropping* is 12 pixels for VGA, 6 pixels
    for CIF, and 3 pixels for QCIF (for each side).

-   no *Spatial Rotation or* *Vertical or Horizontal Re-scaling* is
    allowed

-   

-   no Spatial *Picture Jitter* is allowed. Spatial picture jitter is
    defined as a temporally varying horizontal and/or vertical shift.

For a description of offset and gain in the context of this testplan see
Annex IX. This Annex also includes the method for calculating offset and
gain in PVSs.

No Reference Models should not need calibration

Reduced Reference Models must include temporal registration if the model
needs it. Temporal misalignment of no more than +/-0.25s is allowed.
Please note that in subjective tests, the start frame of both the
reference and its associated HRCs are matched as closely as possible.
Spatial offsets are expected to be very rare. It is expected that no
post-impairments are introduced to the outputs of the encoder before
transmission. Spatial registration will be assumed to be within (1)
pixel. Gain, offset, and spatial registration will be corrected, if
necessary, to satisfy the calibration requirements specified in this
test plan.

The organizations responsible for creating the PVSs shall check that
they fall within the specified calibration and registration limits. The
PVSs will be double-checked by one other organization. After testing has
been completed any PVS found to be outside the calibration limits shall
be removed from the data analyzes. ILG will decide if a suspect PVS is
outside the limits.

# Objective Quality Model Evaluation Criteria

This chapter describes the evaluation metrics and procedure used to
assess the performance of an objective video quality model as an
estimator of video picture quality in a variety of applications.

## Evaluation Procedure

The performance of an objective quality model is characterized by three
prediction attributes: accuracy, monotonicity and consistency.

The statistical metrics root mean square (rms) error, Pearson
correlation, and outlier ratio together characterize the accuracy,
monotonicity and consistency of a model's performance. The calculation
of each statistical metric is performed along with its 95% confidence
intervals. To test for statistically significant differences among the
performance of various models, the F-test will be used.

The statistical metrics are calculated using the objective model outputs
and the results from viewer subjective rating of the test video clips.
The objective model provides a single number (figure of merit) for every
tested video clip. The same tested video clips get also a single
subjective figure of merit. The subjective figure of merit for a video
clip represents the average value of the scores provided by all subjects
viewing the video clip.

Objective models cannot be expected to account for (potential)
differences in the subjective scores for different viewers or labs. Such
differences, if any, will be measured, but will not be used to evaluate
a model's performance. "Perfect" performance of a model will be defined
so as to exclude the residual variance due to within-viewer,
between-viewer, and between-lab effects

The evaluation analysis is based on DMOS scores for the FR and RR
models, and on MOS scores for the NR model. Discussion below regarding
the DMOS scores should be applied identically to MOS scores. For
simplicity, only DMOS scores are mentioned for the rest of the chapter.

The objective quality model evaluation will be performed in three steps.
The first step is a monotonic rescaling of the objective data to better
match the subjective data. The second calculates the performance metrics
for the model and their confidence intervals. The third tests for
differences between the performances of different models using the
F-test.

## Data Processing

Prior to any data analysis, the ILG will perform an inspection of the
subjective test data. Any source sequences presented in the test with a
MOS rating of \<4 will be identified and the file will be examined. If,
in the opinion of the ILG the poor MOS vaues for these source sequences
are due to inferior quality then they shall be removed and not included
in the subsequent data analysis. This data inspection will be completed
prior to proponents submitting their objective data to the ILG.

### Calculating DMOS Values

The data analysis will be performed using the difference mean opinion
score (DMOS). DMOS values are calculated on a per subject per PVS basis.
The appropriate hidden reference (SRC) is used to calculate the DMOS
value for each PVS. DMOS values will be calculated using the following
formula:

DMOS = MOS (PVS) -- MOS (SRC) + 5

In using this formula, a DMOS of 5 indicates 'Excellent' quality and a
DMOS of 1 indicates 'Bad' quality. Any DMOS values greater than 5 (i.e.
where the processed sequence is rated better quality than its associated
hidden reference sequence) will be considered valid and included in the
data analysis.

### Mapping to the Subjective Scale

Subjective rating data often are compressed at the ends of the rating
scales. It is not reasonable for objective models of video quality to
mimic this weakness of subjective data. Therefore, in previous video
quality projects VQEG has applied a non-linear mapping step before
computing any of the performance metrics. A non-linear mapping function
that has been found to perform well empirically is (1)

$\text{DMOSp} = \text{ax}^{3} + \text{bx}^{2} + \text{cx} + d$$\text{DMOSp} = \frac{b1}{1 + e^{- b2 \ast (\text{VQR} - b3)}}$

Where DMOSp is the predicted DMOS, and the VQR is the model's computed
value for a clip-HRC combination. The weightings *a*, *b* and *c* and
the constant *d* are obtained by fitting the function to the data
\[DMOS, VCR\]. This non-linear mapping procedure will be applied to each
model's outputs before the evaluation metrics are computed.

If the cubic polynomial rescaling does not properly converge for all the
models, then a logisitc monotonic rescaling will be applied to all the
models.

$\text{DMOSp} = \frac{b1}{1 + e^{- b2 \ast (\text{VQR} - b3)}}$ (2)

where DMOSp is the predicted DMOS, and VQR is the model's computed value
for a clip-HRC combination. The parameters b1, b2, b3 are found from
fitting the function to the data \[DMOS, VCR\]. This non-linear mapping
procedure will be applied to each model's outputs before the evaluation
metrics are computed.

### Averaging Process

Primary analysis of model performance will be calculated per processed
video sequence. Secondary analysis of model performance may be
calculated and reported on (1) averaged data, by averaging all SRC
associated with each HRC (DMOS~H~), and on (2) averaged data, by
averaging all HRC associated with each SRC (DMOS~S~).

### Aggregation Procedure

The evaluation of the objective metrics is performed in two steps. In
the first step, the objective metrics are evaluated per experiment. In
this case, the evaluation/statistical metrics are calculated for all
tested objective metrics. A comparison analysis is then performed based
on significance tests. In the second step, an aggregation of the
performance results is considered. The aggregation will be performed by
taking the average values for all three evaluation metrics for all
experiments (see section 8.3).

## Evaluation Metrics

Once the mapping has been applied to objective data, the three
evaluation metrics: root mean square error, Pearson correlation
coefficient and outlier ratio are determined. The calculation of each
evaluation metric is performed along with its 95% confidence interval.

### Pearson Correlation Coefficient

The Pearson correlation coefficient R (see Equation 2) measures the
linear relationship between a model's performance and the subjective
data. Its great virtue is that it is on a standard, comprehensible scale
of -1 to 1 and it has been used frequently in similar testing.

X

$R = \frac{\sum_{i = 1}^{N}{(\text{Xi} - \overline{X}) \ast (\text{Yi} - \overline{Y})}}{\sqrt{\sum_{}^{}{(\text{Xi} - \overline{X)}}^{2}} \ast \sqrt{\sum_{}^{}{(\text{Yi} - \overline{Y)}}^{2}}}$
(2)

Xi denotes the subjective score DMOS and Yi the objective DMOSp one. N
represents the total number of video samples considered in the analysis.

It is known \[1\] that the statistic z (3) is approximately normally
distributed and its standard deviation is defined by (4). Equation (3)
is called Fisher-z transformation.

$z = 0\text{.}5 \cdot \text{ln}\left( \frac{1 + R}{1 - R} \right)$ (3)

$\sigma_{z} = \sqrt{\frac{1}{N - 3}}$ (4)

The 95% confidence interval for the correlation coefficient is
determined using the Gaussian distribution, which characterizes the
variable z and it is given by (5)

$z \pm 2 \ast \sigma$ (5)

**NOTE.** If less than N\<30 samples are used, then the Gaussian
distribution needs to be replaced by the two-tailed t-Student
distribution with t=1.96 \[1\].

.

### Root Mean Square Error

The accuracy of the objective metric is evaluated using the root mean
square error (rmse) evaluation metric.

The difference between measured and predicted DMOS is defined as the
absolute prediction error Perror (6)

$\text{Perror}(i) = \text{DMOS}(i) - \text{DMOS}_{p}(i)$ (6)

where the index *i* denotes the video sample.

The root-mean-square error of the absolute prediction error Perror is
calculated with the formula (7)

$\text{rmse} = \sqrt{\left( \frac{1}{N - d}\sum_{N}^{}{\text{Perror}\lbrack i\rbrack ²} \right)}$
(7)

.

Where N denotes the number of samples and d the number of degrees of
freedom of the mapping function (1).

The root mean square error is approximately characterized by a \^2 (n)
\[1\], where n represents the degrees of freedom and it is defined by
(8)

$n = N - d$ (8)

where N represents the total number of samples.

Using the \^2 (n) distribution, the 95% confidence interval for the rmse
is given by (9) \[1\]

$\frac{\text{rmse} \ast \sqrt{N - d}}{\chi_{0\text{.}\text{95}}^{2}(N - d)} < \text{rmse} < \frac{\text{rmse} \ast \sqrt{N - d}}{\chi_{0\text{.}\text{05}}^{2}(N - d)}$
(9)

The consistency attribute of the objective metric is evaluated by the
outlier ratio OR which represents number of "outlier-points" to total
points N.

$\text{OR} = \frac{\text{TotaNoOutliers}}{N}$ (10)

where an outlier is a point for which

$\left| \text{Perror}(i) \right| > 2 \ast \sigma(\text{DMOS}(i))$ (11)

where σ(DMOS(i)) represents the standard deviation of the individual
scores associated with the video clip i. The individual scores are
approximately normally distributed and therefore twice the σ value
represents the 95% confidence interval. Thus, 2 \* σ(DMOS(i))value
represents a good threshold for defining an outlier point.

The outlier ratio represents the proportion of outliers in N number of
samples. Thus, the binomial distribution could be used to characterize
the outlier ratio. The outlier ratio is represented by a distribution of
proportions \[1\] characterized by the mean (12) and standard deviation
(13)

$p = \frac{\text{TotalNoOutliers}}{N}$ (12)

$\sigma_{p} = \sqrt{\frac{p \ast (1 - p)}{N}}$ (13)

For N\>30, the binomial distribution, which characterizes the proportion
p, can be approximated with the Gaussian distribution . Therefore, the
95% confidence interval of the outlier ratio is given by (14)

$\pm 2 \ast \sigma_{p}$ (14)

**NOTE.** If less than N\<30 samples are used, then the t-Student
distribution with t=1.96 \[1\] can be used instead..

##  Statistical Significance of the Results

### Significance of the Difference between the Correlation Coefficients

The test is based on the assumption that the normal distribution is a
good fit for the video quality scores' populations. The statistical
significance test for the difference between the correlation
coefficients uses the H~0~ hypothesis that assumes that there is no
significant difference between correlation coefficients. The H~1~
hypothesis considers that the difference is significant, although not
specifying better or worse.

The test uses the Fisher-z transformation (3) \[1\]. The normally
distributed statistic (15) is determined for each comparison and
evaluated against the 95% t-Student value for the two--tail test, which
is the tabulated value t(0.05) =1.96.

  ------------------------------------------------------------------ --------
  $$Z_{N} = \frac{z1 - z2 - \mu_{(z1 - z2)}}{\sigma_{(z1 - z2)}}$$   \(15\)

  where $\mu_{(z1 - z2)} = 0$                                        \(16\)

  and                                                                \(17\)
  $\sigma_{(z1 - z2)} = \sqrt{\sigma_{z1}^{2} + \sigma_{z2}^{2}}$    
  ------------------------------------------------------------------ --------

σ~z1~ and σ~z2~ represent the standard deviation of the Fisher-z
statistic for each of the compared correlation coefficients. The mean
Error: Reference source not found(16) is set to zero due to the H~0~
hypothesis and the standard deviation of the difference metric z1-z2 is
defined by (17). The standard deviation of the Fisher-z statistic is
given by Error: Reference source not found(18):

  ----------------------------------------------------------------- --------
  $$\sigma_{z} = \sqrt{1(N - 3)}$$                                  \(18\)

  ----------------------------------------------------------------- --------

where N represents the total number of samples used for the calculation
of each of the two correlation coefficients.

### Significance of the Difference between the Root Mean Square Errors

Considering the same assumption that the two populations are normally
distributed, the comparison procedure is similarly to the one used for
the correlation coefficients. The H~0~ hypothesis considers that there
is no difference between rmse values. The alternative H~1~ hypothesis is
assuming that the lower prediction error value is statistically
significantly lower. The statistics defined by Error: Reference source
not found(19) has a F-distribution with n1 and n2 degrees of freedom
\[1\].

  ----------------------------------------------------------------------- --------
  $$\zeta = \frac{\text{rmse}_{\text{max}}}{\text{rmse}_{\text{min}}}$$   \(19\)

  ----------------------------------------------------------------------- --------

rmse,max is the highest rmse and rmse,min is the lowest rmse involved in
the comparison. The ζ statistic is evaluated against the tabulated value
F(0.05, n1, n2) that ensures 95% significance level. The n1 and n2
degrees of freedom are given by N1-1, respectively and N2-1, with N1 and
N2 representing the total number of samples for the compared average
prediction errors.

### Significance of the Difference between the Outlier Ratios

As mentioned in paragraph 8.3.3, the outlier ratio could be described by
a binomial distribution of parameters (p, 1-p), where p is defined by
(12). In this case P is equivalent with the probability of success of
the binomial distribution.

The distribution of differences of proportions from two binomially
distributed populations with parameters (p1, 1-p1) and (p2, 1-p2) (where
p1 and p2 correspond to the two compared outlier ratios) is approximated
by a normal distribution for N1, N2 \>30, with the mean:

$\mu_{(p1 - p2)} = \mu(p1) - \mu(p2) = p1 - p2 = 0$ (20)

and standard deviation:

$$
$\sigma_{p1 - p2} = \sqrt{\frac{\sigma(p1)^{2}}{N1} + \frac{\sigma(p2)^{2}}{N2}}$
(21)

The null hypothesis in this case considers that there is no difference
between the population parameters p1 and p2, respectively p1=p2.
Therefore, the mean (20) is zero and the standard distribution (21)
becomes equation (22)

$\sigma_{p1 - p2} = \sqrt{p \ast (1 - p) \ast (\frac{1}{N1} + \frac{1}{N2}})$
(22)(

where N1 and N2 represent the total number of samples of the compared
outlier ratios p1 versus p2. The variable p is defined by 23

$p = \frac{N1 \ast p1 + N2 \ast p2}{N1 + N2}$ (23)

References

\[1\] M. Spiegel, "Theory and problems of statistics", McGraw Hill,
1998.

# Recommendation

The VQEG will recommend methods of objective video quality assessment
based on the primary evaluation metrics defined in Section 8. The Study
Groups involved (ITU-T SG 12, ITU-T SG 9, and ITU-R SG 6) will make the
final decision(s) on ITU Recommendations.

# Bibliography

-   VQEG Phase I final report.

-   VQEG Phase I Objective Test Plan.

-   VQEG Phase I Subjective Test Plan.

-   VQEG FR-TV Phase II Test Plan.

-   Vector quantization and signal compression, by A. Gersho and R. M.
    Gray. Kluwer Academic Publisher, SECS159, 0-7923-9181-0.

-   Recommendation ITU-R BT.500-10.

-   document 10-11Q/TEMP/28-R1.

-   RR/NR-TV Test Plan

Annex I\
Instructions to the Subjects

Notes: The items in parentheses are generic sections for a Subject
Instructions Template. They would be removed from the final text. Also,
the instructions are written so they would be read by the experimenter
to the participant(s).

(*greeting*) Thanks for coming in today to participate in our study. The
study's about the quality of video images; it's being sponsored and
conducted by companies that are building the next generation of video
transmission and display systems. These companies are interested in what
looks good to you, the potential user of next-generation devices.

(*vision tests*) Before we get started, we'd like to check your vision
in two tests, one for acuity and one for color vision. (*These tests
will probably differ for the different labs, so one common set of
instructions is not possible.*)

(*overview of task: watch, then rate*) What we're going to ask you to do
is to watch a number of short video sequences to judge each of them for
"quality" \-- we'll say more in a minute about what we mean by
"quality." These videos have been processed by different systems, so
they may or may not look different to you. We'll ask you to rate the
quality of each one after you've seen it.

(*physical setup*) When we get started with the study, we'd like you to
sit here (point) and the videos will be displayed on the screen there.
You can move around some to stay comfortable, but we'd like you to keep
your head reasonably close to this position indicated by this mark
(point to mark on table, floor, wall, etc.). This is because the videos
might look a little different from different positions, and we'd like
everyone to judge the videos from about the same position. I (the
experimenter) will be over there (point).

(*room & lighting explanation, if necessary*) The room we show the
videos in, and the lighting, may seem unusual. They're built to satisfy
international standards for testing video systems.

(*presentation timing and order; number of trials, blocks*) Each video
will be (*insert number*) seconds (minutes) long. You will then have a
short time to make your judgment of the video's quality and indicate
your rating. At first, the time for making your rating may seem too
short, but soon you will get used to the pace and it will seem more
comfortable. (*insert number*) video sequences will be presented for
your rating, then we'll have a break. Then there will be another similar
session. All our judges make it through these sessions just fine.

(*what you do: judging \-- what to look for*) Your task is to judge the
quality of each image \-- not the [content]{.underline} of the image,
but how well the system displays that content for you. The images come
in three different sizes; how you judge image quality for the different
sizes is up to you. There is no right answer in this task; just rely on
your own taste and judgment.

(*what you do: rating scale; how to respond, assuming presentation on a
PC*) After [judgin]{.underline}*g* the quality of an image, please
[rate]{.underline} the quality of the image. Here is the rating scale
we'd like you to use (*also have a printed version, either hardcopy or
electronic*):

5 Excellent

4 Good

3 Fair

2 Poor

1 Bad

Please indicate your rating by pushing the appropriate numeric key on
the keyboard (button on the screen). If you missed the scene and have to
see it again, press the XXX key. If you push the wrong key and need to
change your answer, press the YYY key to erase the rating; then enter
your new rating. \[Note, this assumes that a program exists to put a
graphical user interface (GUI) on the computer screen between video
presentations. It should feed back the most recent rating that the
subject had input, should have a "next video" button and an "erase
rating" button. It should also show how far along in the sequence of
videos the session is at present. The program that randomly chooses
videos for presentation, records the data, and contains the GUI, should
be written in a language that is compatible with the most commonly used
computers.\]

(*practice trials: these should include the different size formats and
should cover the range of likely quality*) Now we will present a few
practice videos so you can get a feel for the setup and how to make your
ratings. Also, you'll get a sense of what the videos are going to be
like, and what the pace of the experiment is like; it may seem a little
fast at first, but you get used to it.

(*questions*) Do you have any questions before we begin?

(*subject consent form, if applicable; following is an example*)

The Multimedia Quality Experiment is being conducted at the (*name of
your lab*) lab. The purpose, procedure, and risks of participating in
the Multimedia Quality Experiment have been explained to me. I
voluntarily agree to participate in this experiment. I understand that I
may ask questions, and that I have the right to withdraw from the
experiment at any time. I also understand that (*name of lab*) lab may
exclude me from the experiment at any time. I understand that any data I
contribute to this experiment will not be identified with me personally,
but will only be reported as a statistical average.

Signature of participant Signature of experimenter

Name of participant Date Name of experimenter

Annex II\
Example EXCEL Spreadsheet

  --------- ---------- ------------- ----------- ----------- --------- ---------- ------------- ---------------- ---------- --------- ------------ ----------- ----------- ----------- ---------
  **lab**   **test**   **type**      **subject   **month**   **day**   **Year**   **session**   **resolution**   **rate**   **age**   **gender**   **order**   **scene**   **hrc**     **acr
                                     \#**                                                                                                                                              score**

  ntia      mm1        compression   1000        10          3         2005       1             vga              30         47        m            1           susie       hrc1        4

  ntia      mm1        compression   1000        10          3         2005       1             vga              30         47        m            1           susie       hrc2        2

  ntia      mm1        compression   1000        10          3         2005       1             vga              30         47        m            1           susie       hrc3        1

  ntia      mm1        compression   1000        10          3         2005       1             vga              30         47        m            1           susie       reference   5

  ntt       mm2        robust        2003        10          18        2005       2             cif              25         38        f            2           calmob      pktloss1    1

  ntt       mm2        robust        2003        10          18        2005       2             cif              25         38        f            2           calmob      pktloss2    2

  ntt       mm2        robust        2003        10          18        2005       2             cif              25         38        f            2           calmob      biterror1   1

  ntt       mm2        robust        2003        10          18        2005       2             cif              25         38        f            2           calmob      biterror2   3

  ntt       mm2        robust        2003        10          18        2005       2             cif              25         38        f            2           calmob      reference   4

  yonsei    mm3        livenetwork   3018        10          21        2005       1             qcif             30         27        m            1           football    ip1         4

  yonsei    mm3        livenetwork   3018        10          21        2005       1             qcif             30         27        m            1           football    ip2         3

  yonsei    mm3        livenetwork   3018        10          21        2005       1             qcif             30         27        m            1           football    reference   5
  --------- ---------- ------------- ----------- ----------- --------- ---------- ------------- ---------------- ---------- --------- ------------ ----------- ----------- ----------- ---------

Annex III\
Background and Guidelines on Transmission Errors

### Introduction {#introduction-1 .unnumbered}

Transmission errors should be created to emulate a real video service to
ensure that the proponents' models are trained and tested with realistic
video material. There are three major types of transmissions used for
video services today:

### Packet switched radio network {#packet-switched-radio-network .unnumbered}

This kind of transmission is typical for video service in so called 3G
mobile networks. Examples of services are video streaming service, such
as streaming news and sports video clips to a mobile phone, mobile TV
and video shared in parallel with a normal speech call. The transmission
errors are characterized by packet delays, which can be in the range of
10 ms to several seconds, and packet losses that could be massive
(ranging from no losses to 50%). The packet delay might case packet to
be dropped by the video client because they are received too late, or
causing the buffer to run empty in the client. If the buffer runs empty
it causes frame freezing (not currently included in the test plan).
Packet losses will cause image artifacts in the video and possibly video
frame jitter.

Transport errors should be created by running a video streaming service
over a real-time link simulator, where packets can be delayed in with a
delay pattern as in a typical mobile radio network. The link simulator
should also be able to drop packets. Typically packets are dropped when
a buffer somewhere in the network is full, and new packets arriving at
the buffer are dropped. This situation can occur when the link to the
mobile has a lower bandwidth than required by the video stream.

Packet losses are normally bursty, causing the video quality to vary a
lot. A short video streaming sequence might even be played with best
possible quality, even if the bandwidth is limited. Therefore, video
streaming sequences should be longer than 8 to 10 seconds. An 8 to 10
seconds video clip can be cut out from the longer video sequence, from
the part where the transmission errors have caused the desired video
quality degradation. Note also that the packet size is related to video
quality degradation for a certain packet loss ratio.

### Wireline Internet {#wireline-internet .unnumbered}

Typical service is video streaming to a PC with fixed Internet
connection. Network congestion causes packet losses in the network
switches. Random and periodic packet loss *can* occur due to faulty
equipment. However, bursty packet losses are the most common loss type.
Packet loss ratio is in the range from 0% to 50%. Packets are delayed
with delay ranging from 2 ms to several seconds.

Transmission errors should be created with a bursty packet loss model,
as expected for Internet bottlenecks.

### Circuit switched radio network {#circuit-switched-radio-network .unnumbered}

A typical service is video telephony. The transmission errors are
characterized by bursty loss of data. Chunks of data (packets are not
used in circuit switched transmission) are lost. Block (radio blocks)
error rates are typically ranging from 0.2% to 5% when averaged over a
couple of seconds. Momentarily the error rate can be 100%.

Transport errors should be created by applying error masks on a bit
stream. Errors in the mask should have a bursty pattern to mimic a radio
interface, such as a WCDMA 64 kbps circuit switched radio bearer. Note
that the size of the blocks over the simulated transport link is
correlated to video quality. Within limits the larger block size the
better quality for a certain block error rate. Block size can for
example be 160 or 300 bytes.

### Summary of transmission error simulators {#summary-of-transmission-error-simulators .unnumbered}

+-----------+---------------------------------+------------------------+
| **        | **Model**                       | **Typical error        |
| Transport |                                 | rates**                |
| link      |                                 |                        |
| type**    |                                 |                        |
+-----------+---------------------------------+------------------------+
| Packet    | Link simulator delaying and     | Packet delay in the    |
| switched  | dropping packages. Delay based  | range from 10 ms to 5  |
| radio     | on bit/block errors over a      | s.                     |
| network   | radio link. Drop based on       |                        |
|           | overflow in a network buffer    | Bursty packet loss in  |
|           | due to low bandwidth. The       | the range 0% to 50%    |
|           | packet delay should be          | (for an average over   |
|           | introduced as in a real radio   | one or a few seconds)  |
|           | network. Typical target         |                        |
|           | networks are GSM, WCDMA or CDMA |                        |
|           | radio networks.                 |                        |
+-----------+---------------------------------+------------------------+
| Wireline  | Link simulator dropping         | Packet delay in the    |
| Internet  | packets, as expected when the   | range 2 ms to 5        |
|           | buffer in an Internet switch    | seconds (high value    |
|           | overruns. As described in       | when for example a     |
|           | literature packet losses can be | satellite link Is      |
|           | modeled with a Markov chain     | used). Bursty packet   |
|           | with two states representing no | losses in range from   |
|           | loss/loss. See for example      | 0% to 50%              |
|           | \[2\] below for example of link |                        |
|           | model.                          |                        |
+-----------+---------------------------------+------------------------+
| Circuit   | Link simulator dropping chunks  | Typical block error    |
| switched  | of data. Alternative is to      | rates (over a radio    |
| radio     | apply an error mask to a bit    | link) are ranging from |
| network   | stream. The error mask should   | 0.2% to 5% (average    |
|           | have been made by simulating a  | over a couple of       |
|           | radio link. The bit stream      | seconds)               |
|           | should be a H.223 bit stream,   |                        |
|           | which is used for video         |                        |
|           | telephony. See reference \[1\]  |                        |
|           | below.                          |                        |
+-----------+---------------------------------+------------------------+

Table 1 Summary of transmission error simulators

*Note:* A video service might use multiple transport links. Thus, it is
possible to use a combination of simulators to get realistic transport
errors. A combination of wireline and wireless IP link simulators can be
used to simulate a service, such as video streaming over Internet and a
radio link

**Logging parameters**

Table 2 below describes the parameters to be logged when introducing
transmission errors with a simulator. All parameters are required,
except those explicitly described as "optional".

+-----------+----------------------------------------------------------+
| **Logging | **Logging details**                                      |
| C         |                                                          |
| ategory** |                                                          |
+-----------+----------------------------------------------------------+
| Simulator | -   Type of simulator (packet simulator, circuit         |
| de        |     switched simulator)                                  |
| scription |                                                          |
|           | -   Simulated network (GSM/WCDMA/CDMA/Wireline Internet) |
|           |                                                          |
|           | -   Version of simulator                                 |
|           |                                                          |
|           | -   Hardware/system it was run on                        |
|           |                                                          |
|           | -   General description of how transport errors are      |
|           |     introduced                                           |
+-----------+----------------------------------------------------------+
| Input     | -   Bandwidth limit                                      |
| p         |                                                          |
| arameters | -   System buffer size                                   |
| to        |                                                          |
| simulator | -   Block or bit error rates                             |
| (depends  |                                                          |
| on type   | -   Latency                                              |
| of        |                                                          |
| s         |                                                          |
| imulator. |                                                          |
| Only      |                                                          |
| examples  |                                                          |
| given     |                                                          |
| here)     |                                                          |
+-----------+----------------------------------------------------------+
| Output    | **Packet simulator (wireline and wireless)**             |
| p         |                                                          |
| arameters | -   Average packet loss ratio in percent                 |
| from      |                                                          |
| simulator | -   Length of window to calculate packet loss ratio      |
|           |                                                          |
|           | -   Number of total packets                              |
|           |                                                          |
|           | -   Average packet delay in ms                           |
|           |                                                          |
|           | -   Sequence number of lost packets (optional)           |
|           |                                                          |
|           | -   Distribution of packet delay (optional)              |
|           |                                                          |
|           | -   Packet size distribution (optional)                  |
|           |                                                          |
|           | **Circuit switched simulator**                           |
|           |                                                          |
|           | -   Average block and/or bit error rate (BLER/BER)       |
|           |                                                          |
|           | -   Block size over transport link                       |
|           |                                                          |
|           | -   Maximum block error rate                             |
+-----------+----------------------------------------------------------+
| Decoder   | -   General description of decoder (name, vendor)        |
|           |                                                          |
|           | -   Version of decoder                                   |
|           |                                                          |
|           | -   Post filter used (if known)                          |
|           |                                                          |
|           | -   Error concealment used (if known)                    |
+-----------+----------------------------------------------------------+

Table 2 Parameters to be logged when introducing transmission errors

.

### References {#references .unnumbered}

1.  ITU-T Recommendation H.223, Multiplexing protocol for low bit rate
    multimedia communication.

2.  B. Girod, K. Stuhlmüller, M. Link and U. Horn. "Packet Loss
    Resilient Internet Video Streaming". SPIE Visual Communications and
    Image Processing 99, January 1999, San Jose, CA

ANNEX IV

Fee and Conditions

VQEG intends to enable everybody who is interested in contributing to
the work as a proponent to participate in the assessment of video
quality metrics and to do so even if the proponent is not able to
finance more than the regular participation fee as laid forth in this
Annex (see below for details of the fees). On the other side VQEG will
produce video databases which are extremely valuable to those developing
video metrics. An organization cannot get access to these databases
without, at a minimum, substantially participating in the VQEG work.
VQEG has decided that all proponents must provide at least one database
(or a comparable contribution) which fulfils the requirements laid out
in Sections 4, 5 and 6 of this testplan in order to gain access to the
subjective databases produced in the Multimedia tests. A comparable
contribution should be agreed by the other proponents and could include
such things as providing test sequences and/or running HRCs.If an
organization has no facilities to create such a database by itself, it
may contract a recognized subjective test facility to do so on its
behalf. If an organization is lacking the financial resources to fulfil
this obligation, it can ask other proponents or the ILGs to run its
model on the VQEG databases. In this case the party will not be granted
direct access to the video databases, but the party is still able to
participate in the assessment of their models after paying the regular
participation fee to the Independent Lab Group (ILG).

ANNEX V

(Owner: Kjell Brunnstrom)

Subjective Test Software Package and Required Computer Specification

**Introduction**

The program **acrvqwin-beta2** is a program to run subjective
experiments for video quality in Windows environment, using the
ACR-method It is designed to present the video on a computer screen,
using the picture sizes QCIF, CIF and VGA, synchronized with the refresh
of the display. This is implemented using DirectX.

**System Requirements**

The program uses a multithread function, so it requires a Intel based
(AMD has not been tested) computer with two processors or a processor
that supports multithreading. The CPU speed should be at least 2 GHz.
The graphics card should support yuv to rgb conversion and have at least
256 MByte of video memory. The system should have primary memory of at
least 512 MB. The program can be run on Windows 2000 and Windows XP.

**Using the program**

### Installation and preparation {#installation-and-preparation .unnumbered}

After downloading and extracting the files, the file
**acrvqwin-beta2.exe** has to be placed in the same library as the five
dll files: libmatlb, libmcc,libmx, libmat and libut libut (should be
obtained together i.e in the same distribution, with the executable
file, so versions of the dlls match the executable). The setup-file
(setup.seq) can be placed anywhere as the program will let you specify
the path at the start of the experiment. To be able to run the
experiment program a setup-file, see also below, has to be used in order
to set some of the parameters in the program and also specify the path
and name of the avi-files that should be used during the experiment. To
specify your avi-files you write the filenames just below the path to
the directory they are in. Each filename must be written on a separate
row, as the program will treat each line of text as a filename.

### Running the program  {#running-the-program .unnumbered}

The program is started in the normal way in Windows e.g double-clicking
on the icon. The program will initially present a dialog box for
selecting setup-file (this makes it possible to have different
setup-files for various experiment stored at the same time) to use for
the experiment.

After choosing the setup-file the program will enter the experiment
environment, the screen will have the same grey-level as has been
specified with the parameter Background. To start the first sequence you
can either press the s button on the keyboard or the left button on the
mouse and the video sequence will be displayed at the centre of the
screen. When the sequence is finished a dialog box will appear in order
to get the subjects rating of the perceived video quality. This
procedure will continue until the experiment is done and the program
will automatically exit. You can at any time quit the current experiment
by pressing the Esc key.

The order of the sequences does not match the order of the filenames in
the setup-file. The program randomises the order at the start of the
program. The random numbers are drawn from a uniform distribution. The
results are stored in two output-files that have the same name as the
parameter SubjectId with an extension of either log or dat. The log-file
shows the results in the exact order as the sequences have been shown.
The dat-file sorts the data regardless of the randomisation that has
been done by the program, in order to make it easier to analyse the
results from a statistical point of view. The data in the dat-file are
stored in exactly the same order as in the setup-file.

If the Esc key is being pressed during an experiment the program will
store the necessary data in a .svd file to be able to restore the
experiment later. The .svd file will be created in the folder specified
by the parameter Path and have the filename specified by the parameter
SubjectId. Next time the program starts it will ask you if you want to
restore the aborted experiment and if selecting yes the experiment will
continue from where it was aborted. If you don't want the program to
keep asking you if you want to restore an experiment, simply delete the
.svd file.

For mixing 25-fps and 30-fps sequences, the parameter ScreenRefreshFreq
must be set to 60 Hz. The program will then run the 30-fps sequences as
normal and try to run the 25-fps sequences as close to 25 fps as
possible. As 60 is evenly divided by 30, each frame will be displayed
two screen refresh cycles and the timing between the frames will be
constant in the 30-fps sequences. This can't be done with the 25-fps
sequences and the solution applied in this program is to alternate
between displaying a frame 2 or 3 screen refresh cycles. The program
uses the serie: 2, 3, 2, 3, 2. In order to distinguish between the
differences in framerate of the sequences the framerate parameter in the
avi-file infoheader must be valid.

### Setup-file parameters {#setup-file-parameters .unnumbered}

PixelDepth: The only supported mode for this version is 16 bit with the
format YUV 4:2:2

ScreenHeight: The height of the screen measured in pixels.

ScreenWidth: The width of the screen measured in pixels.

ScreenRefreshFreq: The update frequency of the screen.

VideoFrameRate: The number of frames shown per second.

Background: The grey-level of the background in the experiment
environment, where 0 is black and 255 is white.

NumberOfSeries: This parameter is used to set how many times each
sequence will be played.

UseImageRatings: Decides whether to use an image or text to describe the
different ratings for the subject.

ImagePathRatings: Specifies the path to the image if the parameter
UseImageRatings is set to true.

ImagePathNoRating: Specifies the path to the image to be shown if
UseImageRatings is set to true and the subject has missed to rate the
sequence.

Rating5-Rating1: The text used to describe the different ratings if
UseImageRatings is set to false.

NoRating: This text is shown if the subject misses to rate the sequence
and UseImageRat-ings is set to false.

SubjectId: Specifies the filename for the .dat and .log file.

NoOfImagesInSeq: The number of frames that will be displayed from the
avi-file. This parameter makes it possible to decide the length of the
sequences from the setup-file.

Path: Specifies the path to the directory holding the avi-files to be
used. The .dat and .log file will be placed here.

### Example of a setup-file {#example-of-a-setup-file .unnumbered}

\[Sequence\]

PixelDepth = 16

ScreenHeight = 1024

ScreenWidth = 1280

ScreenRefreshFreq = 60

VideoFrameRate = 30

Background = 128

NumberOfSeries =3

UseImageRatings = FALSE

ImagePathRatings = \"C:\\MyPath\\mybitmap1.bmp\"

ImagePathNoRating = \"C:\\MyPath\\mybitmap2.bmp\"

Rating5 = \"Excellent\"

Rating4 = \"Good\"

Rating3 = \"Fair\"

Rating2 = \"Poor\"

Rating1 = \"Bad\"

NoRating = \"The sequence has not been rated\"

SubjectId = \"Subject\"

NoOfImagesInSequence = 300

Path = \"C:\\MyPath\"

myavi1.avi

myavi2.avi

myavi3.avi

**Term of usage**

This software is provided as is. No warranty or support is given. It may
be used within the VQEG for research purposes. Copyright 2005 Acreo AB,
Sweden.

ANNEX VI

(Owner: Quan Huynh-Thu)

Method for Post-Experiment Screening of Subjects

**Method**

The rejection criterion verifies the level of consistency of the raw
scores of one viewer according to the corresponding average raw scores
over all viewers. Decision is made using correlation coefficient.
Analysis per PVS and per HRC is performed for decision.

Linear Pearson correlation coefficient per PVS for one viewer vs. all
viewers:

$$r1(x,y) = \frac{\sum_{i = 1}^{n}{x_{i}y_{i} - \frac{\left( \sum_{i = 1}^{n}x_{i} \right)\left( \sum_{i = 1}^{n}y_{i} \right)}{n}}}{\sqrt{\left( \sum_{i = 1}^{n}{x_{i}^{2} - \frac{\left( \sum_{i = 1}^{n}x_{i} \right)^{2}}{n}} \right)\left( \sum_{i = 1}^{n}{y_{i}^{2} - \frac{\left( \sum_{i = 1}^{n}y_{i} \right)^{2}}{n}} \right)}}$$

Where

xi = MOS of all viewers per PVS

yi = individual score of one viewer for the corresponding PVS

n = number of PVSs

i = PVS index.

Linear Pearson correlation coefficient per HRC for one viewer vs. all
viewers:

$$r2(x,y) = \frac{\sum_{i = 1}^{n}{x_{i}y_{i} - \frac{\left( \sum_{i = 1}^{n}x_{i} \right)\left( \sum_{i = 1}^{n}y_{i} \right)}{n}}}{\sqrt{\left( \sum_{i = 1}^{n}{x_{i}^{2} - \frac{\left( \sum_{i = 1}^{n}x_{i} \right)^{2}}{n}} \right)\left( \sum_{i = 1}^{n}{y_{i}^{2} - \frac{\left( \sum_{i = 1}^{n}y_{i} \right)^{2}}{n}} \right)}}$$

Where

xi = condition MOS of all viewers per HRC, i.e. condition MOS is the
average value across all PVSs from the same HRC

yi = individual condition MOS of one viewer for the corresponding HRC

n = number of HRCs

i = HRC index

Rejection criteria

1\. Calculate r1 and r2 for each viewer

2\. Exclude a viewer if (r1\<0.75 AND r2 \<0.8) for that subject

Note: The reason for using analysis per HRC (r2) is that a subject can
have an individual content preference that is different from other
viewers, making r1 to decrease, although this subject may have voted
consistently. Analysis per HRC averages out individual's content
preference and check consistency across error conditions.

$$r(x,y) = \frac{\sum_{i = 1}^{n}{x_{i}y_{i} - \frac{\left( \sum_{i = 1}^{n}x_{i} \right)\left( \sum_{i = 1}^{n}y_{i} \right)}{n}}}{\sqrt{\left( \sum_{i = 1}^{n}{x_{i}^{2} - \frac{\left( \sum_{i = 1}^{n}x_{i} \right)^{2}}{n}} \right)\left( \sum_{i = 1}^{n}{y_{i}^{2} - \frac{\left( \sum_{i = 1}^{n}y_{i} \right)^{2}}{n}} \right)}}$$
xi = mean score of all observers for the PVS

yi = individual score of one observer for the corresponding PVS

n = number of PVSs

i = PVS index

R(xi or yi) is the ranking order

Final rejection criteria for discarding an observer of a test

The Spearman rank and Pearson correlations are carried out to discard
observer(s) according to the following
conditions:$r(x,y) = \left\lbrack 1 - \frac{6 \times \sum_{i = 1}^{n}\left\lbrack R\left( x_{i} \right) - R\left( y_{i} \right) \right\rbrack^{2}}{n^{3} - n} \right\rbrack$
ANNEX VII

Encrypted Source Code Submitted to VQEG

Proponents are entitled to submit a file with encrypted source code
along with their model's object code. This submission is not required
but is offered in case there is a bug in the software that can be fixed
without changing the algorithm. Normally, there would be no software
updates possible after the submission of the object code.

In order for this option to be exercised the proponent must encrypt the
source code with a readily available encryption program (see below for a
freeware example) and send the password protected file to two ILG labs
(CRC and Acreo). If it is determined by the proponent that a bug is
present in the software, then the proponent must discuss the situation
with the ILG Co-Chairs. If the Co-Chairs agree that a bug fix should be
tried, then a procedure must be agreed to in order for the proponent to
make the change to the code in the presence of the ILG member. This
could be done in person or perhaps by telephone.

The proponent would make the change and the ILG member would verify that
it was not an algorithm change. The code would be recompiled and tested
in the presence of the ILG member. The revised code should be
re-encrypted with a different password.

The encrypted file can be transported electronically or physically. It
needs to be sent to both ILG contacts below:

ILG contacts:

+----------------------------------+-----------------------------------+
| Kjell Brunnstrom                 | Filippo Speranza                  |
|                                  |                                   |
| Acreo                            | CRC                               |
|                                  |                                   |
| Stockholm, Sweden                | Ottawa, Canada                    |
|                                  |                                   |
| +4686327732                      | +1 613-998-7822                   |
|                                  |                                   |
| Kjell.Brunnstrom@acreo.se        | filippo.speranza@crc.ca           |
+----------------------------------+-----------------------------------+

A good freeware encryption program:

Blowfish Advanced CS 2.57

http://www.hotpixel.net/software.html (click on Blowfish Advanced CS --
Installer)

This software offers several encryption algorithms. The one that allows
the largest key (448 bits) is Blowfish. It is also in German and
English.

Source files should be zipped and then encrypted.

Other encryption programs can be used but if they are not free then the
proponent is responsible for purchasing the program for the ILG if
necessary.

ANNEX VIII

Approved Conversion Tools

## Transformation of source test sequences to UYVY AVI files {#transformation-of-source-test-sequences-to-uyvy-avi-files .unnumbered}

Transformation of the source test sequences as described in chapter 6.1
(e.g., from Rec. 601 525-line to QCIF) shall be performed using the
following tools:

  --------------------- -------------------------------------------------
  **Tool**              **Web Resources**

  Avisynth 2.5.5        <http://www.avisynth.org/>

  AviSynth Filters\     <http://www.avisynth.org/warpenterprises/>
  (RawSource,           
  KernelDeint)          

  VirtualDub 1.6.11     <http://www.virtualdub.org/>

  ffdshow 20050303      <http://ffdshow.sourceforge.net/>
  --------------------- -------------------------------------------------

For loading a sequence in raw uncompressed UYVY 4:2:2 format (as the
VQEG format, see FRTV\
Phase I video file examples at
<ftp://vqeg.its.bldrdoc.gov/SDTV/VQEG_PhaseI/TestSequences/>) the
"RawSource" plugin for AviSynth is used. The sequences are opened with
the \"UYVY\" mode.

De-interlacing will be performed according chapter 6.1.4 using the
de-interlacing AviSynth plugin "KernelDeint". If the de-interlacing
using KernelDeint results in source sequence that has serious artifacts,
the Blendfield or Autodeint may be used as alternative methods for
de-interlacing.

Cropping and Rescaling is done according chapter 6.1.5, using AviSynth
build-in "LanczosResize" function.

The following script can be used as a template for the the
transformations. See the Avisynth documentation for detailed information
on what each command does.

\# This function limits the memory space (in MB) used by the script
(should be used)

SetMemoryMax(100)

\# The RawSource plugin loads raw YUV 4:2:2, 4:2:0, etc. videos

RawSource(\"c:\\calmob.yuv\",720,486,\"UYVY\")

\# AssumeFPS() forces the framerate of the video.

AssumeFPS(30)

\# Deinterlacing

KernelDeint(order=0)

\# Cropping

crop(36,3,-38,-3)

\# Resizing

LanczosResize(176,144)

The scripts are saved using the extension ".avs" and then loaded into
VirtualDub (File-\>OpenVideoFile).

Within VirtualDub, video sequences will be saved to AVI files using
Video Compression option (Video\
-\>Compressor) \"ffdshow Video Codec\", configured with the
\"Uncompressed\" decoder and the UYVY color space. For the Color Depth
(Video-\>Color Depth), the setting "4:2:2 YCbCr (UYUV)" is used as
output format. The processing mode (Video-\>) is set to "Full processing
mode".

The tools and scripts may be downloaded at:\
Tools/Approved/ directory on <ftp://mmpretest@132.163.64.167/>

## AviSynth Scripts for the common transformations {#avisynth-scripts-for-the-common-transformations .unnumbered}

**PAL to QCIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",720,576,\"UYVY\")

AssumeFPS(25)

KernelDeint(order=1)

crop(38,0,644,576)

LanczosResize(176,144)

**PAL to CIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",720,576,\"UYVY\")

AssumeFPS(25)

KernelDeint(order=1)

crop(8,0,702,576)

LanczosResize(352,288)

**PAL to VGA**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",720,576,\"UYVY\")

AssumeFPS(25)

KernelDeint(order=1)

crop(38,0,644,576)

LanczosResize(640,480)

**NTSC to QCIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",720,486,\"UYVY\")

AssumeFPS(30)

KernelDeint(order=0)

crop(36,3,-38,-3)

LanczosResize(176,144)

**NTSC to CIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",720,486,\"UYVY\")

AssumeFPS(30)

KernelDeint(order=0)

crop(36,3,-38,-3)

LanczosResize(352,288)

**NTSC to VGA**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",720,486,\"UYVY\")

AssumeFPS(30)

KernelDeint(order=0)

crop(8,3,704,480)

LanczosResize(640,480)

**HD720 to QCIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",1280,720,\"UYVY\")

AssumeFPS(30)

crop(200,0,880,720)

LanczosResize(176,144)

**HD720 to CIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",1280,720,\"UYVY\")

AssumeFPS(30)

crop(200,0,880,720)

LanczosResize(352,288)

**HD720 to VGA**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",1280,720,\"UYVY\")

AssumeFPS(30)

crop(160,0,960,720)

LanczosResize(640,480)

**HD1080 to QCIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",1920,1080,\"UYVY\")

AssumeFPS(30)

KernelDeint(order=1)

crop(300,0,1320,1080)

LanczosResize(176,144)

**HD1080 to CIF**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",1920,1080,\"UYVY\")

AssumeFPS(30)

KernelDeint(order=1)

crop(300,0,1320,1080)

LanczosResize(352,288)

**HD1080 to VGA**

SetMemoryMax(100)

RawSource(\"c:\\calmob.yuv\",1920,1080,\"UYVY\")

AssumeFPS(30)

KernelDeint(order=1)

crop(240,0,1440,1080)

LanczosResize(640,480)

## UYVY Raw to UYVY AVI {#uyvy-raw-to-uyvy-avi .unnumbered}

These tools convert raw uncompressed UYVY 4:2:2 files to uncompressed
UYVY AVI files. The following tools are available:

**AviSynth,VirtualDub, ffdshow**

Use the procedure described in "Transformation of source test sequences
to UYVY AVI files" without performing the cropping and resizing step
within the AviSynth script.

*The following tools are not approved in the MM test plan:*

**SwissQual**

Tools/SwissQual/Conversion_Tools/UYVYIntoAVI/ directory on
<ftp://mmpretest@132.163.64.167/>

**NTIA**

The "Laboratory VQM" tool available from NTIA has this capability. The
UYVY AVI output file is limited to 2GB (AVI Version 1.0). This tool may
be obtained at:

<http://www.its.bldrdoc.gov/n3/video/vqmsoftware.htm>

## UYVY Raw to RGB AVI {#uyvy-raw-to-rgb-avi .unnumbered}

These tools convert raw uncompressed UYVY files to uncompressed RGB AVI
files. The following tools are available:

**AviSynth,VirtualDub**

Use the procedure described in "Transformation of source test sequences
to UYVY AVI files" without performing the cropping and resizing step
within the AviSynth script and save the file as described next.

Within VirtualDub, video sequences will be saved to AVI files using
Video Compression option (Video\
-\>Compressor) \"Uncompressed RGB/YCbCr\". For the Color Depth
(Video-\>Color Depth), the setting "24 bit RGB (888)" is used as output
format. The processing mode (Video-\>) is set to "Full processing mode".

*The following tool is not approved in the MM test plan:*

**SwissQual**

Tools/SwissQual/Conversion_Tools/UYVYToAVI/ directory on
<ftp://mmpretest@132.163.64.167/>

## RGB AVI to UYVY AVI {#rgb-avi-to-uyvy-avi .unnumbered}

These tools convert uncompressed RGB AVI files to uncompressed UYVY AVI
files using the agreed color space conversion in section 6.1.3. The
following tools are available:

**VirtualDub, ffdshow**

The RGB Avi file will be loaded into VirtualDub (File-\>OpenVideoFile)
and then saved according the following steps.

Within VirtualDub, video sequences will be saved to AVI files using
Video Compression option (Video\
-\>Compressor) \"ffdshow Video Codec\", configured with the
\"Uncompressed\" decoder and the UYVY color space. For the Color Depth
(Video-\>Color Depth), the setting "4:2:2 YCbCr (UYUV)" is used as
output format. The processing mode (Video-\>) is set to "Full processing
mode".

*The following tool is not approved in the MM test plan:*

**SwissQual**

Tools/SwissQual/Conversion_Tools/RGBtoYUV/ directory on
<ftp://mmpretest@132.163.64.167/>

## Processing and Editing Sequences {#processing-and-editing-sequences-1 .unnumbered}

Two capture methods have been approved and descried in chapter 6.3.9.
The tools will intercept RGB video being sent to a computer monitor and
saves this video to an uncompressed AVI file.

**SwissQual**

Free demonstration system for capturing streaming media (the full
version can be bought from SwissQual):

Tools/SwissQual/Capturing/ directory on on
<ftp://mmpretest@132.163.64.167/>

The full system is capable of capturing QuickTime, Real Media, and
Windows Media streams and includes a Media Server. The tool captures the
image shown on the monitor, or more precisely from the memory (space)
that Windows sends to the graphics card. A frame is captured only if new
data is available. That is why there is a file created that contains the
variable frame rate information. Please see:

Tools/SwissQual/VQEG_SQ_Capturing_Sequences_V2.pdf on
<ftp://mmpretest@132.163.64.167/>

To meet the desired VQEG file format definitions, the captured video
data must be converted to constant frame rate and from RGB to YUV. These
conversions are already implemented in the full version of the capturing
tools.

Please contact Pero Juric (<pero.juric@swissqual.com>) for any further
information.

**NTT**

PIFREC 1.0 (Lossless PC Video & Voice Recorder). The PC capture system
uses a capture board to receive the signals passed from a PC to its
monitor, without adding any processing load to the PC, and stores them
while retaining high video quality.

More Information about PIFREC can be found at:
<http://www.ntt-at.com/products_e/pifrec/index.html>

Please contact Mr. Takawo Adachi (<at-hama@ntt-at.co.jp>) for any
further information.

*The following tool is not approved in the MM test plan:*

**Linux**

These capture tools consist of a set of Linux system libraries that
hijack the output of various players. The captured video data as well as
a file with time stamps is saved to the disk. The tools developed by
Marcus Barkowski from the University of Erlangen are available at this
location:

Tools/playout_capure.tgz on <ftp://mmpretest@132.163.64.167/>

## Calibration {#calibration .unnumbered}

These tools verify that the processed video sequences meet the
calibration limits (e.g., temporal shifts, spatial shifts, spatial
scaling, gain and level offset) specified by the test plan.

*The following tool is not approved in the MM test plan:*

**NTIA**

The "Laboratory VQM" tool available from NTIA has the ability to
estimate spatial registration, temporal registration, and gain/level
offset. This tool may be obtained at:

<http://www.its.bldrdoc.gov/n3/video/vqmsoftware.htm>

## UYVY Decoder to UYVY Raw / UYVY AVI {#uyvy-decoder-to-uyvy-raw-uyvy-avi .unnumbered}

This tool intercepts UYVY video from a video decoder (before being
converted to RGB for monitor display) and saves this video to a UYVY Raw
or UYVY AVI file.

*The following tools are not approved in the MM test plan:*

The following video decoders output some form of uncompressed YUV video
and hence RGB color space conversions can be avoided:

  ------------------------- ---------------------------------------------------- ---------------------------
  **Tool**                  **Web Resources**                                    **Output Format**

  MPEG-2 Reference Codec    [www.mpeg.org](http://www.mpeg.org/)                 Outputs YUV 4:2:2 and YUV
                                                                                 4:2:0

  MainConcept MPEG-2 Codec  [www.mainconcept.com](http://www.mainconcept.com/)   Since the MainConcept
                                                                                 decoder is a DirectShow
                                                                                 filter, its output can be
                                                                                 an AVI file. DirectShow
                                                                                 filter outputs a range of
                                                                                 YUV formats in addition to
                                                                                 RGB.

  H.264 (AVC) Joint Video                                                        Outputs YUV 4:2:0
  Team (JVT) Reference                                                           
  Codec                                                                          

  MainConcept H.264 codec   [www.mainconcept.com](http://www.mainconcept.com/)   Outputs a range of YUV
                                                                                 formats
  ------------------------- ---------------------------------------------------- ---------------------------

## Notes {#notes .unnumbered}

VirtualDub is also capable of saving UYVY AVI files without using
ffdshow. The following settings are used to get correct results.

*The following procedure is not approved in the MM test plan:*

Within VirtualDub, video sequences will be saved to AVI files using
Video Compression option (Video-\>Compressor) \"Uncompressed
RGB/YCbCr\". For the Color Depth (Video-\>Color Depth), the setting
"4:2:2 YcbCr (UYUV)" is used as output format. The processing mode
(Video-\>) is set to "Full processing mode".

ANNEX IX

Definition and Calculating Gain and Offset in PVSs

Before computing luma (Y) gain and level offset, the original and
processed video sequences should be temporally aligned. One delay for
the entire video sequence may be sufficient for these purposes. Once the
video sequences have been temporally aligned, perform the following
steps.

Horizontally and vertically cropped pixels should be discarded from both
the original and processed video sequences.

The Y planes will be spatially sub-sampled both vertically and
horizontally by the following factors: 16 for VGA, 8 for CIF and 4 for
QCIF. This spatial sub-sampling is computed by averaging the Y samples
for each block of video (e.g., for VGA one Y sample is computed for each
16 x 16 block of video). Spatial sub-sampling should minimize the impact
of distortions and small spatial shifts (e.g., 1 pixel) on the Y gain
and level offset calculations.

The gain (*g*) and level offset (*l*) are computed according to the
following model:

$\underline{P} = g\underline{O} + l$ (1)

where *[O]{.underline}* is a column vector containing values from the
sub-sampled original Y video sequence, *[P]{.underline}* is a column
vector containing values from the sub-sampled processed Y video
sequence, and equation (1) may either be solved simultaneously using all
frames, or individually for each frame using least squares estimation.
If the latter case is chosen, the individual frame results should be
sorted and the median values will be used as the final estimates of gain
and level offset.

Least square fitting is calculated according the following formula:

*g* = ( *R~OP~* -- *R~O~R~P~* )/( *R~OO~* -- *R~O~R~O~* ), and (2)

*l* = *R~P~* - *g* *R~O~* (3)

where *R~OP,\ ~*R~OO,~ R~O~ and R~P~ are:

*R~OP~* = (1/*N*) *O*(*i*) *P*(*i*) (4)

*R~OO~* = (1/*N*) \[*O*(*i*)\]^2^ (5)

*R~O~* = (1/*N*) *O*(*i*) (6)

*R~P~* = (1/*N*) *P*(*i*) (7)

[^1]: Test laboratories can keep data from invalid viewers if they
    consider this to be of valuable information to them but they must
    not include them in the VQEG data.

[^2]: This will allow conducting an ACR experiment within 1 hour,
    including practice clips and a comfortable break during the
    experiment.

[^3]: Note that the term 'block' does not refer to a visual degradation
    such as blocking errors (or blockiness) but refers to errors in the
    transport stream (transport blocks).