Compressed television signal recording and reproducing apparatus

In a compressed signal recording and reproducing apparatus, a table-of-contents generator extracts user selected representative frames from among frames of an input compressed television signal that can be identified by specified additional information, and generates table-of-contents data representing contents of a specified number of the user selected representative frames. A recording signal processor arranges the input compressed television signal, table-of-contents data, and positional information relating to positions for recording the individual user selected representative frames data, respectively, at specified positions of the recording medium. The apparatus further includes a reproduction signal processor for outputting table-of-contents data recorded at a specified position in the recording medium for exhibiting contents of a plurality of user selected representative frames, from among the reproduction data.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a compressed television signal recording 
and reproducing apparatus for recording television signals compressed by 
means of a high efficiency compression algorithm and for reproducing the 
compressed television signals to a decoder. 
2. Description of the Prior Art 
High efficiency digital coding technologies for video and other image 
signals have progressed significantly in recent years. Particular 
attention has been given to inter-frame predictive coding techniques as a 
means of reducing redundancy on the time-base axis, and international 
standards for video signal coding techniques have been established. One of 
these is the ISO-13818 specification, which is commonly known as MPEG-2 
for the Motion Picture Expert Group of the ISO. 
This method reduces redundancy on the time base by inter-frame predictive 
coding, and reduces redundancy on the spatial base by discrete cosine 
transformation (DCT) coding. Predictive error is reduced by motion 
compensation during inter-frame prediction to improve coding efficiency. 
The coded data is generally recorded using variable length block units, 
macro block units, MBS units, picture units, and group-of-picture (GOP) 
units. 
Systems for combining and packetizing the video and audio coded data in an 
MPEG signal have been established as a means of transmitting such variable 
length coded data. In this system, the coded data is first converted to 
variable length packets called a "packetized elementary stream" (PES); 
these PES packets are then divided into fixed length packets called the 
"transport stream packets" (TSP). Auxiliary information used, for example, 
to synchronize the audio and video or to identify multiplexed programs is 
also written to the TSP. 
As described in An experimental study on a home-use digital VCR (IEEE 
International Conference on Consumer Electronics, Jun. 6-9, 1989; WPM8.6), 
when recording a base band signal in a digital video cassette recorder 
(DVCR), the input video signal is compressed, then an error correction 
signal is added to the compressed video signal for coding the signal for 
recording, and the coded signal is then recorded on a magnetic tape. 
During reproduction, the signal read from the magnetic tape is detected 
and processed for error correction, and then decoded to output the video 
signal. Note that the video signal is recorded to the magnetic tape in 
fixed length packet units. 
When an MPEG or other compressed television signal is recorded and 
reproduced, the signal is packetized in units of a fixed number of bits in 
the transmission sequence of the signal sent from the encoder. During 
reproduction, the read-out packets are reconnected in the sequence to 
reproduce the original signal, which is then transmitted to the decoder. 
With this conventional method, however, the following problems develop when 
the input data is data compressed by inter-frame coding as in the case of 
MPEG signals. 
Specifically, during fast forward, fast reverse and other special 
reproduction modes, since a reproducing head scans across the recording 
tracks, it is impossible to reproduce frame data or to reproduce auxiliary 
signals necessary for the decoder to perform the decoding operation. 
Secondly, it is also impossible to know contents of individual portions of 
a recording tape which are recorded on the tape over, for example, two 
hours or so. 
SUMMARY OF THE INVENTION 
The object of the present invention is to solve the above-described 
problems of the conventional signal recording and reproducing apparatus. 
More particularly, the object of the present invention is to make known 
the contents of individual recorded portions of the tape. 
The compressed television signal recording and reproducing apparatus 
according to a first aspect of the present invention comprises; 
on its recording portion, a table-of-contents data generating means for 
extracting representative frames that can be identified by specified 
additional information, from among frames of an input compressed 
television signal, and then generating table-of-contents data representing 
contents of a specified number of said representative frames; an 
arrangement means for arranging the input compressed television signal at 
a first specified position of a recording medium, arranging the 
table-of-contents data at a second specified position of the recording 
medium, and arranging positional information relating to positions for 
recording the individual representative frames data at a third specified 
position of the recording medium; and a recording means for recording the 
data arranged by said arrangement means onto the recording medium, 
the apparatus further comprising: 
on its reproduction side, a reproducing means for obtaining reproduction 
data by reproducing data recorded in a recording medium; a 
table-of-contents data output means for outputting table-of-contents data 
recorded at a specified position in the recording medium for exhibiting 
contents of a plurality of representative frames, from among the 
reproduction data; a selection information acquiring means for acquiring 
information from an external device as to which to select among the 
representative frames exhibited by the table-of-contents frame; and an 
output means for delivering an output signal containing data of a 
representative frame selected by the selection information acquiring means 
out of the representative frames. 
By this arrangement, since table-of-contents frames are recorded 
independently, a table-of-contents frame can be easily reproduced in the 
reproduction mode. Further, since the relationship of the representative 
frames exhibited in a table-of-contents frame to the position on the 
recording medium, it becomes possible to easily move to a position where a 
representative frame selected in the reproduction mode is recorded. 
According to another feature of the present invention, the 
table-of-contents frames are recorded independently, whereby it becomes 
easy to reproduce a table-of-contents frame in the reproduction mode. 
Further, the relationship between programs within a signal transmitted 
with a plurality of programs multiplexed and the representative frames 
exhibited within the table-of-contents frame is recorded. By this 
arrangement, it becomes possible to easily select a program of the 
representative frame selected in the reproduction mode. 
Moreover, according to further another feature of the present invention, 
the compressed television signal recording and reproducing apparatus 
comprises, a positional information extracting means for extracting 
positional information of data of one representative frame selected out of 
the representative frames, and a search means for searching for a position 
on the recording medium exhibited by the representative frame according to 
the obtained positional information and for making a reproduction started 
at the position on the recording medium. 
By this constitution, a table-of-contents frame can be reproduced from the 
recording medium on which table-of-contents frames are recorded 
independently. Further, it becomes possible to easily move to a position 
where a selected is representative frame is recorded, based on the 
relationship between the representative frame exhibited within the 
table-of-contents frame and the position an the recording medium. 
Moreover, according to another further feature of the present invention, 
the compressed television signal recording and reproducing apparatus 
comprises, an identification information extracting means for extracting 
identification information for identifying data of one representative 
frame selected by the selection information acquiring means out of the 
representative frames, and an identifying means for identifying the 
reproduction signal by using the identification information. 
By this constitution, a table-of-contents frame can be reproduced from the 
recording medium on which table-of-contents frames are recorded 
independently. Further, it becomes possible to easily select a program of 
a selected representative frame, by confirming the relationship between 
the programs within a signal transmitted and multiplexed with a plurality 
of programs and the representative frames exhibited within the 
table-of-contents frame.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The embodiments of the present invention will be described hereinbelow with 
reference to the accompanying drawings. It is to be noted that components 
denoted by like numerals have the same construction and function 
throughout the description. 
EMBODIMENT 1 
FIG. 1 shows a construction of a compressed television signal recording and 
reproducing apparatus according to a first embodiment of the present 
invention 
Referring to FIG. 1, the compressed television signal recording and 
reproducing apparatus of the first embodiment comprises a memory 1 for 
storing input signals supplied via an input terminal, a table-of-contents 
frame generator circuit 2 connected between the memory 1 and a recording 
signal processor circuit 4 for generating a table-of-contents frame, a 
representative frame positional information detector circuit 3 also 
connected between the memory 1 and the recording signal processor circuit 
4 for detecting a representative frame positional information. The inputs 
of the recording signal processor circuit 4 are connected to the outputs 
of the memory 1, table-of-contents frame generator circuit 2 and 
representative frame positional information detector circuit 3. The output 
of the recording signal processor circuit 4 is connected to a magnetic 
recording tape 7 serving as a recording medium via a recorder circuit 5 
and via a recording head 6. The magnetic recording tape is an example of a 
sequential-access recording medium, i.e., a recording medium in which data 
is recorded or accessed in order, as opposed to a random-access recording 
medium, in which data may be recorded or accessed in any order. 
The apparatus further comprises a key input device 8 for inputting external 
data via a key input, and a microcomputer 9 for controlling various parts 
of the apparatus. The apparatus further comprises a reproducer circuit 11 
for reproducing data from the recording medium 7 via a reproducing head 
10. The output of the reproducer circuit 11 is connected to a reproduction 
signal processor circuit 12 the outputs (A, B) of which are further 
connected to a selector switch 14 and another output (C) of which is 
connected to a representative frame positional information extractor 13. 
The representative frame positional information extractor 13 for 
extracting representative frame positional information is connected 
between the microcomputer 9 and the reproduction signal processor circuit 
12. The apparatus further comprises a tape drive controller circuit 15 for 
controlling a tape drive based on a command from the microcomputer 9. 
The operation of the compressed television signal recording and reproducing 
apparatus thus constructed is described below. 
It is to be noted that, as an input compressed television signal applied to 
the apparatus of the present embodiment, not only the image signal data 
but also audio signal data and added information signal data when required 
are inputted to the apparatus. 
When a user intends to operate the apparatus while setting in a recording 
mode, the user commands the microprocessor 9 by operating the key input 
device 8 to specifically set the apparatus to the recording mode. 
As to the selection and designation of a representative frame, the user 
selects and designates, as the representative frame, a scene well 
representing the contents of each scene on the memory 1 via the key input 
device 8 during a search process from among the compressed television 
signal accumulated in the memory 1. 
When there in no such selection of a representative frame specified by a 
user, an index code identifying a track at which the recording/stopping 
process starts is recorded each time starting of the recording and 
stopping operation, and the corresponding frame of that portion is 
designated as a representative frame. Alternatively, borders between 
commercials and programmed subject matters may be detected and recorded 
each time it happens, and the frames at which these codes are recorded can 
be used as the representative frames. As described above, the 
representative frames may be selected and designated using any of these or 
similar operations. The image data selected as the representative frames 
is once stored in the memory 1. 
The representative frame positional information detector circuit 3 detects 
a recording track of the magnetic tape to which these representative 
frames are located, and outputs the track number of the detected frame 
positions as the representative frame address information. 
Once the representative frames are selected and the addresses thereof are 
determined, then the table-of-contents frame generator circuit 2 compiles 
a table-of-contents frame using the representative frames. Namely, the 
table-of-contents frame generator 2 generates table-of-contents data 
representing contents of a specified number of the representative frames 
by extracting representative frames that can be identified by specified 
additional information, from among frames of an input compressed 
television signal. 
FIG. 9 shows a construction of the table-of-contents frame generator 2 
which comprises an image picture data extractor 91, a partial decoder 92, 
a reduction picture data generator 93, a memory 94, and a 
table-of-contents data arranging unit 95. 
In response to a timing control generated by the microcomputer 9, the image 
picture data extractor 91 extracts only the image signal data selected as 
the representative frames on the memory 1, and then the extracted data is 
fed to the partial decoder 92 where data of partial components, for 
example, of a D.C. signal portion of each block is decoded. The decoded 
D.C. signal data of each block corresponds to an average value of the data 
in each block, which corresponds to the value of the pixels in the case 
where a reduced frame is produced regarding each block as one pixel. The 
resultant data of each pixel of the reduced frame is divided into blocks 
by means of the reduction picture data generator 93. Thereafter, the 
contents of each resultant block are coded in a format of an image picture 
data to thereby obtain the reduction image picture data. The reduction 
image picture data is fed from the reduction picture data generator 93 to 
the table-of-contents data arranging unit 95 via the memory 94 for storing 
the reduced frame data, and then the reduction image picture data are 
rearranged and synthesized in groups each containing a predetermined 
number of images to thereby sequentially generate multiple 
table-of-contents frames as shown in FIG. 5. 
In this embodiment, although only the D.C. components are extracted and 
decoded by the partial decoder 92, this decoding operation can be made 
while containing other DCT coefficients. 
Moreover, when the contents in each of the blocks are coded in a format of 
image data by means of the reduction picture data generator 93, the 
discrete cosine transformation (DCT) can be utilized for coding. 
Alternatively, by calculating the average value, only the D.C. components 
are calculated to be coded. Otherwise, by providing ROM or the like, a 
corresponding coded data can be read. 
In this process, the table-of-contents frame generator generates 
table-of-contents data in such a data format as to be decodable by a 
decoding device associated with the input compressed television signal. 
By formatting this multiple image frame in the same data-format used for 
formatting single images, it is possible, even in a recording medium 
containing both motion and still images, to reproduce images from the 
multiple representative frames in an index frame format. Thus, the user 
can efficiently determine the content of the recording medium even though 
only the image signal data containing the added information desired by the 
user is displayed in a compressed format. 
In addition, because the recording position of the original frames from 
which the reduced index images were generated is recorded as auxiliary 
information to a predetermined recording area, it is possible to easily 
execute high speed searches for locating and reproducing the desired 
content. It is to be noted that the representative frame is not 
necessarily required to be a still image, and the multiple frame can be 
implemented even for image data of motion pictures. Namely, even motion 
image frames can be indexed to is the multiple image frame. 
The recording signal processor circuit 4 multiplexes the input compressed 
television signal, the table-of-contents data and positional information 
relating to positions for recording the individual representative frames 
data to be arranged respectively at specified areas 100, 101 and 102 of 
the recording medium, as shown in FIG. 6. The recording signal processor 4 
repeatedly arranges the table-of-contents data a plural number of times. 
In more detail, the recording signal processor circuit 4 multiplexes the 
input compressed television data, table-of-contents data and positional 
information data of the representative frames so that the input data from 
the memory 1 is recorded to the first area 100, as shown in FIG. 6, and 
that the table-of-contents data supplied from the table-of-contents frame 
generator 2 is recorded to the second area 101, and that the positional 
information data supplied from the representative-frame positional 
information detector 3 is recorded to the third area 102, and then the 
multiplexed signal is outputted from the recording signal processor 4 in a 
multiplexed fashion, which the resultant signal is to be supplied to the 
recorder circuit 5. 
The recorder circuit 5 then applies error correction coding to the 
multiplexed signal data, and further modulates the resultant signal for 
recording. The modulated data signal output from the recorder circuit 5 is 
recorded onto the magnetic recording medium 7 such as a magnetic tape via 
the recording head 6. 
Next, the operation of reproducing data in the apparatus during a 
reproduction mode will be described hereinbelow. 
The data signal read out from the magnetic tape 7 via the reproduction head 
10 is subjected to demodulation and error correction by means of the 
reproducer circuit 11 the output of which is applied as the reproduction 
signal to the reproduction signal processor circuit 12. The reproduction 
signal processor circuit 12 determines the location of the original 
recording packet based on the header information of the present recording 
packet and the like with respect to the reproduction signal. It is to be 
noted here that the location of the original recording packet denotes as 
to at which position on the recording medium was recorded each recording 
packet of the signal obtained in the reproduction operation, namely, as to 
which number of sync block (i.e., recording packet) on which number of 
track in the case of a magnetic recording tape. 
The recording packets belonging to the areas 100, 101, and 102 as shown in 
FIG. 6, respectively, are outputted in batch in the sequence they were 
recorded, as a signal. A used for normal reproduction modes, as a signal B 
used for table-of-contents frame display, and as a signal C having such 
auxiliary data as the positional information of the recorded 
representative frames used for extracting representative-frame positional 
information. 
When the user chooses to display the table-of-contents frame by means of 
the key input device 8, the microcomputer 9 controls the switch 14 to 
select the signal B to be output, thus outputting the table-of-contents 
frame data to an external device to be displayed. If the table-of-contents 
frame data is formatted identically to the normal reproduction mode data, 
a decoder (not shown) externally connected the apparatus can directly 
decode the table-of-contents frame data, and the table-of-contents frame 
can thus be displayed. 
In the meantime, the recorder circuit 5 may be controlled by the 
microcomputer 9 so as to record, at a desired position in the recording 
medium 7, switching information for switching between a reproduction 
output (B) of table-of-contents data and a reproduction output (A) of 
input compressed television data in the output operation process. 
It is to be noted that the table-of-contents data may include not only 
image data but also audio data. When audio data is also included in the 
table-of-contents data, it is also possible to reproduce the audio data 
corresponding to user manipulation of the key input device 8 when the 
table-of-contents is displayed, or to reproduce audio data related to or 
describing the representative frames in the displayed table-of-contents. 
Alternatively, the table-of-contents data generator 2 may reproduce image 
picture data of the representative frames out of image picture data of a 
compressed television signal that has previously been recorded on the 
recording medium, and thereafter generates table-of-contents data using 
the image picture data of a specified number of the representative frames. 
When the user has selected by the key input device 8 a frame for which the 
user desires to search, from among the representative frames in the 
displayed table-of-contents frame, the microcomputer 9 informs the 
representative-frame positional information extractor 13 of the number of 
the selected representative frame desired to be searched from among three 
reduction frames displayed in the table-of contents frame as shown in FIG. 
5. The representative-frame positional information extractor 13 restores 
the track position of the selected representative frame among from the 
signal C supplied from the reproduction signal processor 12, and then the 
restored track position of the selected representative frame is 
transmitted to the microcomputer 9. 
The microcomputer 9 commands the tape drive control circuit 15 to 
fast-forward or fast-reverse the tape to the restored track position. The 
tape drive control circuit 15 fast-forwards or fast-reverses the tape 
while comparing the track numbers recorded on the tape with reference to 
the targeted track position. When the tape drive reaches the targeted 
track position, the operation mode of the apparatus is switched to a 
normal reproduction one, and the normal reproduction of data signal is 
started. 
At this stage, the switch 14 is turned over to output the signal A, and the 
input signal portion indicated by the representative frame is restored and 
output to the external devices. Over these steps of operation, the scene 
represented by the table-of-contents frame display and the search of the 
selected representative frame can be retrieved. 
FIG. 2 shows a construction of a compressed television signal recording and 
reproducing apparatus according to a second embodiment of the present 
invention. 
Referring to FIG. 2, the apparatus of the second embodiment has a similar 
construction to that of the first embodiment except for the feature that a 
memory 21 is connected between the output terminal of the apparatus and 
the selector switch 14 so that the output data of the selector switch 14 
is outputted to the external via the memory 21. 
The compressed television signal recording and reproducing apparatus of 
this embodiment comprises, a table-of-contents data generator 2 for 
generating data of a table-of-contents frame, a recording signal processor 
4 for arranging the input compressed television signal at a first 
specified position 100 of the recording medium, arranging the data of a 
table-of-contents frame at a second specified position 101 of the 
recording medium, and arranging identification information of the 
individual representative frames at a third specified position 102 of the 
recording medium. 
In the second embodiment with the above constitution shown in FIG. 2, since 
the table-of-contents frames are recorded independently, it becomes easy 
to reproduce a table-of-contents frame in the reproduction mode. Further, 
since the relationship between programs within a signal transmitted with a 
plurality of programs multiplexed and the representative frames exhibited 
within the table-of-contents frame is recorded, then it becomes possible 
to easily select a program of the representative frame selected in the 
reproduction mode. 
In more detail, the operation of the compressed television signal recording 
and reproducing apparatus constructed as described above is now described 
while set in the normal recording and reproduction mode. 
When the user designates the microcomputer 9 to set the apparatus to be 
operated in a recording mode via the key input device 8, the apparatus 
turns into the recording mode. An input compressed television signal is 
directly supplied to the recording signal processor circuit 4 via an input 
terminal of the apparatus. The input compressed television signal is so 
formatted as to be recorded at an area 100 shown in FIG. 6 by the 
recording signal processor circuit 4. 
The signal output from the recording signal processor 4 is fed to the 
recorder circuit 5 where the recording-formatted signal is added with an 
error correcting code and further modulated to thereby obtain modulated 
signal data. The resulting modulated data signal is recorded onto the 
recording medium 7 by means of the recording head 6. 
Next, the operation of selecting a representative frame is described 
hereinbelow. The selection of a representative frame is designated to the 
microcomputer 9 via the key input device 8 by the user, and the apparatus 
turns to the representative-frame selection mode by this designation. A 
reproduction signal derived from the recording medium 7 via the 
reproduction head 10 is subjected to demodulation and error correction by 
means of the reproducer circuit 11, and then the resultant signal is 
outputted to the reproduction signal processor circuit 12 as a 
reproduction signal. 
The reproduction signal processor circuit 12 discriminates the position of 
the original recording packet based on the header information and the like 
of the recording packet with respect to the reproduction signal. Recording 
packets belonging to the area 100 are restored and outputted as a signal A 
for use in the normal reproduction mode. The user selects a scene well 
representing the contents of individual scenes as the representative 
frames during a search process while viewing the reproduced contents and 
designates the scenes as the representative frames via the key input 
device 8. 
The representative-frame positional information detector 3 detects which 
track the frame selected as the representative frame is located on the 
tape, and outputs the detected track number as the representative-frame 
positional information data to be applied to the recording signal 
processor 4. Thus, the user can be informed of the correspondence between 
the representative frame and the track number on the tape on which the 
portion represented by the representative frame is recorded. 
Next, since the operation of the table-of-contents frame generator 2 is the 
same as in the first embodiment, its description is omitted here. However, 
it is necessary that the area 101 shown in FIG. 6 where table-of-contents 
data is recorded can be overwritten independently of the area 100 where 
the input data has been recorded. 
The reproduction mode is also the same as in the first embodiment, and its 
description is omitted here. In the present embodiment, the representative 
frame car be selected while the contents that have already been recorded 
on the recording medium are being reproduced. Thus, the volume of the 
memory 21 can be smaller than the memory 1 as a further advantage. 
FIG. 3 shows an essential feature of a recording and reproducing apparatus 
according to a third embodiment of the present invention. 
As shown in FIG. 3, the apparatus of the present embodiment is of the same 
construction and operation as in the case where only the recording portion 
in the first embodiment shown in FIG. 1 is concerned. 
In this embodiment, referring to FIGS. 1 and 3, the table-of-contents data 
generator 2 reproduces only image data of representative frames that can 
be identified by specified additional information, from among a compressed 
television signal that has previously been recorded on a recording medium, 
and then generates table-of-contents frame data representing contents of a 
specified number of representative frames. In this case, the recording 
signal processor 4 arranges the input compressed television signal at a 
first specified area 100 of a recording medium, arranging the 
table-of-contents data at a second specified area 101 of the recording 
medium, and arranging identification information for identifying data of 
the individual representative frames at a third specified area 102 of the 
recording medium. 
By recording table-of-contents data on the recording medium as in the 
present embodiment, a tape that can afford to display a table-of-contents 
frame in the reproduction mode can be produced. This is effective 
particularly for prerecorded tapes on which software has been recorded for 
sales purpose. 
FIG. 4 shows a construction of a recording and reproducing apparatus 
according to a fourth embodiment of the present invention. 
Referring to FIG. 4, the apparatus of the present embodiment is of the same 
construction and operation as in the case where only the reproduction 
portion in the first embodiment shown in FIG. 1 is concerned. 
In this embodiment, referring to FIGS. 1 and 4, reproduction data is 
obtained by reproducing data recorded on a recording medium. The 
table-of-contents data has been recorded for exhibiting contents of a 
plurality of representative frames and has been recorded at a specified 
position 101 in the recording medium. The information as to which to 
select out of the representative frames exhibited by the table-of-contents 
frame is acquired from the external via the key input device 8. The 
positional information extractor 13 extracts positional information 
relating to the recording position of data of one representative frame 
selected by the user from among the representative frames. The tape drive 
controller 15 serving as a search means searches for a position on the 
recording medium exhibited by the representative frame according to the 
obtained positional information and makes a reproduction started at the 
position on the recording medium. 
By this constitution, a table-of-contents frame can be reproduced from the 
recording medium on which table-of-contents frames are recorded 
independently. Further, it becomes possible to easily move to a position 
where a selected representative frame is recorded, based on the 
relationship between the representative frame exhibited within the 
table-of-contents frame and the position on the recording medium. 
In a deck main body of the present embodiment, the components on the 
recording side portion are omitted for lower prices, so that 
table-of-contents data are not generated. However, the display of a 
table-of-contents frame is possible when a tape on which software has been 
recorded is reproduced for sales purpose, as an advantage. 
FIG. 7 shows a construction of a recording and reproducing apparatus 
according to a fifth embodiment of the present invention. 
Referring to FIG. 7, the apparatus of the fifth embodiment has a similar 
construction to that of the first embodiment except for the features that, 
a representative-frame channel information detector circuit 71 and a 
representative-frame channel information extractor 73 shown in FIG. 7 are 
provided instead of the representative-frame positional information 
detector circuit 3 and the representative-frame positional information 
extractor circuit 13 shown in FIG. 1, respectively, and that a channel 
selector 72 is added between the reproduction signal processor 12 and the 
selector switch 14 while removing the tape drive controller 15 of FIG. 1. 
The operation of the compressed television signal recording and reproducing 
apparatus of the fifth embodiment is described below. 
The recording and reproducing apparatus is supplied with a multiplexed 
compressed television signal as its input signal in which compressed 
television signals of multiple channels are multiplexed. When the user 
designates a recording mode to the microcomputer 9 via the key input 
device 8, the apparatus is put into the recording mode. 
The user selects and designates via the key input device 8 a scene well 
representing the contents of scenes of individual channels as a 
representative frame as shown in FIG. 8 during a search process, from 
among the compressed television signal accumulated in the memory 1. 
With no designation by the user, picture and audio data of each channel at 
that time are extracted, and the frame of the extracted portion is 
regarded as a representative frame. Otherwise, a boundary between a 
commercial and a program is detected, and a video signal and an audio 
signal that come immediately after the commercial are recorded for each 
channel, so that the frame of that portion is regarded as a representative 
frame. The representative frame may be selected by either one of the above 
two types of operation. 
The representative-frame channel information detector circuit 71 detects a 
relationship between the number of the frame selected as the 
representative frame and the number of a transmission channel transmitted 
from a broadcasting station, which is, for example, a so-called PID code 
for classifying transmission packets in the MPEG, and then outputs the 
detection result as channel information data. 
Next, a table-of-contents frame is generated based on the representative 
frame by the table-of-contents frame generator circuit 2. The process of 
generating table-of-contents data is the same as in the first embodiment, 
thus its description being omitted here. 
The recording signal processor circuit 4 multiplexes the input data 
supplied, table-of-contents data and positional information data, so that 
the input data from the memory 1 is recorded to an area 100, as shown in 
FIG. 6, the table-of-contents data supplied from the table-of-contents 
frame generator 2 is recorded to an area 101, and the positional 
information data supplied from the representative-frame positional 
information detector 3 is recorded to an area 102, and then the 
multiplexed signal is outputted from the recording signal processor 4 in a 
multiplexed fashion to be supplied to the recorder circuit 5. 
It is to be noted that, in the present embodiment, by recording the motion 
pictures of the channels at the same time point as the representative 
frames, in parallel to the area 101, it is easily known what are the 
contents of data in each channel of the input signal that has been 
recorded at the area 100 at the same time point. 
The recorder circuit 5 then applies error correction coding to the 
multiplexed signal data, and further modulates the resultant signal for 
recording. The modulated data signal output from the recorder circuit 5 is 
recorded onto the magnetic recording medium 7 such as a magnetic tape via 
the recording head 6. 
Next, the reproduction operation of the apparatus during a reproduction 
mode will be described hereinbelow. 
The data signal read out from the magnetic tape 7 via the reproduction head 
10 is subjected to demodulation and error correction by means of the 
reproducer circuit 11 the output of which is applied as the reproduction 
signal to the reproduction signal processor circuit 12. The reproduction 
signal processor circuit 12 determines the location of the original 
recording packet based on the header information of the present recording 
packet and the like with respect to the reproduction signal. The recording 
packets belonging to the areas 100, 101, and 102 as shown in FIG. 6, 
respectively, are outputted in batch in the sequence they were recorded, 
as a signal A used for normal reproduction modes, as a signal B used for 
table-of-contents frame display, and as a signal C having such auxiliary 
data as the positional information of the recorded representative frames 
used for extracting representative-frame positional information. 
When the user chooses to display the table-of-contents frame by means of 
the key input device 8, the microcomputer 9 controls the switch 14 to 
select the signal B to be output, thus outputting the table-of-contents 
frame data to an external device to be displayed. If the table-of-contents 
frame data is formatted identically to the normal reproduction mode data, 
a decoder (not shown) externally connected the apparatus can directly 
decode the table-of-contents frame data, and the table-of-contents frame 
can thus be displayed. 
When the user has selected by the key input device 8 a frame for which the 
user desires to search, from among the representative frames in the 
displayed table-of-contents frame, the microcomputer 9 informs the 
representative-frame channel information extractor 73 of the address 
number of the selected representative frame. The representative-frame 
channel information extractor 73 restores the channel number of the 
selected representative frame out of the signal C, and informs the 
microcomputer 9 of the restored channel number. The microcomputer 9 
transmits the resulting channel number to the channel selector circuit 72. 
The channel selector circuit 72 outputs only a transmission packet having 
the transmitted channel number, and in some cases, generates also a dummy 
packet for making the rate constant. 
Over the above steps of operation, the program of the channel indicated by 
the table-of-contents frame display and the selected representative frame 
can be selected and produced. This function can be utilized as an index of 
contents when a plurality of software items are recorded on the recording 
medium, allowing an easy search and reproduction of software on the 
recording medium. 
By this constitution, a table-of-contents frame can be reproduced from the 
recording medium 7 on which table-of-contents frames are recorded 
independently. Further, it becomes possible to easily select a program of 
a selected representative frame, based on the relationship between the 
programs within a signal transmitted while multiplexing a plurality of 
programs, with the representative frames exhibited within the 
table-of-contents frame. 
Although the MPEG signal has been taken as an example of the compressed 
television signal in the present embodiment, it may be replaced with other 
compressed television signals. 
Also although the track arrangement as shown in FIG. 6 has been illustrated 
as an example of the recording areas, the arrangement thereof is at 
discretion. In addition, if the areas 101, 102 are overwritable 
independently of the area 100, it is possible to record and generate 
table-of-contents data separately, which is advantageous in terms of 
apparatus construction and data generation time. 
Also, although a particular channel signal has been selected out of a 
multiplexed signal by an internal channel selection circuit, yet it is 
also possible to output signals of all the channels and select one by 
using a channel selection function built in an external decoder. In this 
case, the user's operability with the decoder can be facilitated by 
finding the channel number of the representative frame selected by the 
representative-frame channel information detector 71, and by displaying 
the channel number on external, or the user can be made easier to switch 
the channel, by sending an operation signal from the deck for a channel 
switch to the decoder. 
According to the present embodiment as described hereinabove, it is 
facilitated to reproduce a table-of-contents frame during reproduction 
mode by recording a table-of-contents frame separately to the program 
content, and it is also facilitated to move quickly to the recording 
location of the selected representative frame during reproduction by 
further recording the relationship between the representative frames 
displayed in the table-of-contents frame and the recording positions of 
said representative frames on the recording medium. 
In addition, the program of the representative frame selected during 
reproduction can be easily located and reproduced by recording the 
relationship between each of the plural programs in the multiplexed input 
signal and the representative frames shown in the table-of-contents frame. 
Furthermore, it should be noted that the embodiments described hereinabove 
shall not be limited to the configurations shown in the block diagrams 
therefor, and various other configurations are possible with the same 
equivalent effects. In addition, signal processing whereby the equivalent 
effects are obtained can also be achieved by means of a signal processor 
and software. 
The recording and reproducing parts of the aforementioned embodiments can 
also be provided separately in discrete apparatuses. 
The number of channels multiplexed to a plural channel multiplexed signal 
may also be any number of channels. 
In addition, the special reproduction mode signals may be generated for any 
number of channels.