JPH06268954A - Digital video disk and device - Google Patents

Abstract

PURPOSE:To suppress the cost increase by compressing a digital video signal for plural channels, applying time division multiplexing to the signal and record ing the result on the same track. CONSTITUTION:Processing circuits 51-53 for three channels compress respectively 1st-3rd channel video signals and an audio signal. Video audio multiplexers/ demultiplexers 81-83 multiplex video data and audio data fed from the processing circuits 51-53 and output the result to a channel multiplexer/ demultiplexer 91. The channel multiplexer/demultiplexer 91 applies time division multiplexing to three channel data received from the multiplexers/demultiplexers 81-83 to synthesize them to one channel data. Thus, the digital video signal for plural channels is compressed and multiplexed in this way and the result is recorded on the same track.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital video disc and a digital video disc device for recording multi-channel video signals.

[0002]

2. Description of the Related Art FIG. 4 shows the configuration of a conventional digital video disk device. The video disk 2 is rotated by the spindle motor 1 at a predetermined speed. The video signal supplied from the recording / reproducing circuit 4 is recorded on and reproduced from the disc 2 by the optical pickup 3.

The recording / reproducing circuit 4 has an input terminal 11 and an output terminal 12. The video signal input from the input terminal 11 is A / D converted by an A / D converter 13, and
It is adapted to be supplied to the image compression encoder / decoder 17. The audio signal input from the input terminal 11 is A / D converted by the A / D converter 14 and then supplied to the audio encoder / decoder 18.

The image compression encoder / decoder 17 is A
The video data input from the / D converter 13 is compressed and encoded, supplied to the buffer memory 20 via the image memory controller 19 and stored therein, and the image data input from the image memory controller 19 is expanded and decoded. , Output terminal 1 via D / A converter 15
It is designed to output to 2. The audio encoder / decoder 18 encodes the audio signal input from the A / D converter 14, and the audio memory controller 21
The audio data read from the buffer memory 22 via the audio memory controller 21 is decoded and output to the output terminal 12 via the D / A converter 16. It is designed to do.

The video / audio multiplexer / demultiplexer 23 synthesizes the video data and audio data supplied from the buffer memory 20 or the buffer memory 22 via the image memory controller 19 or the audio memory controller 21, and adds ECC / error correction. It is adapted to output to the circuit and the digital modulation / demodulation circuit 24. Further, the data supplied from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 24 is separated into video data and audio data, and the image memory controller 19 and the audio memory controller 2 are respectively separated.
The data is output to the buffer memories 20 and 22 via 1.

The RF amplifier 25 amplifies the data supplied from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 24 and supplies it to the optical pickup 3 and also amplifies the data supplied from the optical pickup 3. , ECC addition / error correction circuit and digital modulation / demodulation circuit 24.

In this device, the optical pickup 3
Besides, an optical pickup 33 is provided, and a recording / reproducing circuit 34 corresponding thereto is further provided. Although illustration is omitted, the recording / reproducing circuit 34 is also configured similarly to the recording / reproducing circuit 4.

Next, the operation will be described. In the recording mode, the video signal and the audio signal input to the input terminal 11 are A and D converted by the A / D converters 13 and 14, respectively.
The data is D / D converted and supplied to the image compression encoder / decoder 17 and the audio encoder / decoder 18. The image compression encoder / decoder 17 compresses and encodes the input video data, supplies the video data to the buffer memory 20 via the image memory controller 19, and stores the buffer memory 20. Similarly, the audio encoder / decoder 18 encodes the input audio data, supplies the encoded audio data to the buffer memory 22 via the audio memory controller 21, and causes the buffer memory 22 to store the audio data.

The video / audio multiplexer / demultiplexer 23 includes a buffer memory 2 via an image memory controller 19 and an audio memory controller 21, respectively.
0 and the buffer memory 22 are accessed to read out the video data and audio data stored therein,
Combined as data for one channel. This combined data is an ECC addition / error correction circuit and digital modulation /
The data is input to the demodulation circuit 24, an error detection and correction code is added, digitally modulated by a predetermined method, and RF
It is supplied to the optical pickup 3 via the amplifier 25.
The optical pickup 3 irradiates the disk 2 with a laser beam corresponding to the input data, and
1 channel of video data and audio data
Record on the book track.

Similarly, mixed data of video data and audio data of another channel output from the recording / reproducing circuit 34 is supplied to the optical pickup 33 and recorded on another track of the disc 2.

In this way, on the disc 2, as shown in FIG. 5, the video data and the audio data of the channel 1 (Ch1) are compressed and recorded on the first track. Similarly, on the second track, channel 2
The video data and audio data of (Ch2) are compressed and recorded.

In the reproduction mode, the optical pickup 3 reproduces the data recorded on the first track of the disc 2 and adds the ECC to / from the RF amplifier 25.
Output to the error correction circuit and digital modulation / demodulation circuit 24. ECC addition / error correction circuit and digital modulation /
The demodulation circuit 24 demodulates the input digital data, performs error detection and correction, and outputs it to the video / audio multiplexer / demultiplexer 23. The video / audio multiplexer / demultiplexer 23 separates the input data into video data and audio data,
The image data is supplied to and stored in the buffer memory 20 and the buffer memory 22 via the image memory controller 19 and the audio memory controller 21, respectively.

The image compression encoder / decoder 17 has a buffer memory 20 via an image memory controller 19.
To read, decompress, and decode the video data written there. This data is D / A
It is D / A converted by the converter 15 and output to the output terminal 12. The audio encoder / decoder 18 also accesses the buffer memory 22 via the audio memory controller 21, reads the audio data written therein, and decodes it. This data is D / A converted by the D / A converter 16 and output to the output terminal 12.

On the other hand, the optical pickup 33 reproduces the digital data recorded on the second track of the disc 2 and outputs it to the recording / reproducing circuit 34. Recording / playback circuit 3
4, the same as in the recording / reproducing circuit 4,
It processes and outputs the video data and audio data reproduced from the second track.

[0015]

In the conventional digital video disc apparatus, the video data of a plurality of channels are independently recorded and reproduced on different tracks as described above. As a result, an independent circuit and mechanism are required for each channel, which not only increases cost, but also has a problem that compatibility with a single-channel device cannot be maintained.

The present invention has been made in view of such circumstances, and is intended to realize a lower cost device while ensuring compatibility with a single channel device. is there.

[0017]

According to a first aspect of the present invention, there is provided a digital video disc for compressing digital video signals of a plurality of channels, time-division multiplexing the digital video signals of a plurality of channels, and compressing and time-division multiplexing. It is characterized in that the digitalized video signals of plural channels are recorded on the same track.

According to a second aspect of the present invention, there is provided a digital video disk device in which A / D converters 63-1 and 63- serving as A / D converting means for A / D converting video signals of a plurality of channels.
2, a multiplexer / demultiplexer 91V as a multiplexing means for time-division multiplexing the video signals of a plurality of channels A / D converted by the A / D converters 63-1 and 63-2, and an A / D converter Image compression encoder / decoder 67V as compression means for compressing the video signals of a plurality of channels A / D-converted by 63-1 and 63-2 before or after being multiplexed by the multiplexer / demultiplexer 91V, and image compression An optical pickup 94 as recording means for recording on a digital video disk 96 video signals of a plurality of channels which are compressed by an encoder / decoder 67V and time-division multiplexed by a multiplexer / demultiplexer 91V.
And an image compression encoder / decoder 67 as a control means for controlling the data so that the transfer bit rate of the digital video disk 96 becomes a value close to the maximum value regardless of the number of channels of the recorded video signal. Is characterized by.

[0019]

In the digital video disc according to the first aspect of the present invention, digital video signals of a plurality of channels are compressed, multiplexed and recorded on the same track. Therefore, it is possible to record video data in basically the same format as a single-channel digital video disc, and it is possible to further reduce the cost.

In the digital video disk device according to the second aspect of the present invention, the data is controlled so that the transfer bit rate of the digital video disk 96 is close to the maximum value regardless of the number of channels of the recorded video signal. To do. Therefore, when the number of channels is small, it is possible to obtain a high quality image.

[0021]

1 is a block diagram showing the configuration of an embodiment of a digital video disk device of the present invention. In this embodiment, processing circuits 51 to 53 for three channels are provided. In the processing circuit 51, the input terminal 6
The video signal input from 1 is A / D converted by the A / D converter 63, and then input to the image compression encoder / decoder 67. In addition, the audio signal input from the input terminal 61 is transferred to the A / D converter 6
After being A / D converted by 4, the audio data is input to the audio encoder / decoder 68.

The image compression encoder / decoder 67 compresses and encodes the input video data, supplies the compressed video data to the buffer memory 70 via the image memory controller 69, and stores the same in the image memory controller 69.
The video data read out from the buffer memory 70 via the is decompressed and decoded, and is output to the output terminal 62 via the D / A converter 65.

The voice encoder / decoder 68 is
The audio data input from the A / D converter 64 is encoded, supplied to the buffer memory 72 via the audio memory controller 71, stored therein, and read out from the buffer memory 72 via the audio memory controller 71. The data is decoded and output to the output terminal 62 via the D / A converter 66.

Although not shown, the processing circuits 52 and 53 have the same configuration as the processing circuit 51.

The video / audio multiplexer / demultiplexer 81 is adapted to multiplex the video data and the audio data input via the image memory controller 69 and the audio memory controller 71, and output them to the channel multiplexer / demultiplexer 91. There is. The video / audio multiplexer / demultiplexer 81 separates the data input from the channel multiplexer / demultiplexer 91 into video data and audio data, and the image memory controller 69.
And is output to the buffer memories 70 and 72 via the audio memory controller 71.

The video / audio multiplexers / demultiplexers 82 and 83 also multiplex the video data and audio data supplied from the processing circuits 52 and 53 and output the multiplexed data to the channel multiplexer / demultiplexer 91 and the channel multiplexer / demultiplexer 91. The data input from 91 is separated into video data and audio data and output to the processing circuits 52 and 53, respectively.

The channel multiplexer / demultiplexer 91 time-division-multiplexes the data of three channels input from the video / audio multiplexer / demultiplexers 81 to 83, synthesizes the data of one channel, and adds ECC / error. Output to the correction circuit and digital modulation / demodulation circuit 92. The channel multiplexer / demultiplexer 91 separates the data input from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92 into data for three channels, and outputs the data to the video / audio multiplexers / demultiplexers 81 to 83, respectively. It is designed to do.

The RF amplifier 93 amplifies the data supplied from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92, outputs the amplified data to the optical pickup 94, and amplifies the data supplied from the optical pickup 94. ECC addition / error correction circuit and digital modulation /
The signal is output to the demodulation circuit 92. The optical pickup 94 outputs a laser beam corresponding to the data input from the RF amplifier 93 to the digital video disc 9
6 to irradiate data to record data and reproduce data recorded on the digital video disc 96,
The output is provided to the F amplifier 93. The digital video disk 96 is rotated by a spindle motor 95 at a predetermined speed.

Next, the operation will be described. In the recording mode, the video signal input to the input terminal 61 is A / D converted by the A / D converter 63, and then input to the image compression encoder / decoder 67 to be compressed and decoded. The decoded video data is supplied to the buffer memory 70 via the image memory controller 69 and stored therein. On the other hand, the audio data input from the input terminal 61 is A / D converted by the A / D converter 64.
After D conversion, it is input to the audio encoder / decoder 68 and encoded. Audio encoder / decoder 6
The audio data encoded by 8 is supplied to and stored in the buffer memory 72 via the audio memory controller 71.

The video / audio multiplexer / demultiplexer 81 includes a buffer memory 7 via an image memory controller 69 and an audio memory controller 71.
0 and 72 are accessed, and the video data and audio data stored therein are read out and combined as data for one channel. Then, the combined data is output to the channel multiplexer / demultiplexer 91.

Similarly, the video data and audio data of the second channel processed by the processing circuit 52 are converted into the video / audio multiplexer / demultiplexer 82.
Is input to the channel multiplexer / demultiplexer 91. The video data and audio data of the third channel processed by the processing circuit 53 are also combined into one-channel data by the video / audio multiplexer / demultiplexer 83 and input to the channel multiplexer / demultiplexer 91.

The channel multiplexer / demultiplexer 91 time-division-multiplexes the input digital data of three channels and converts it into digital data of one channel. This converted state is schematically shown in FIG.

As shown in the figure, the video signals and the audio signals of the first to third channels are respectively compressed to form data for one channel. Further, the control signal Ch1 indicating the channel 1 is arranged at the beginning of the data of the first channel. Similarly, the control signal Ch2 or Ch3 representing the channel 2 or the channel 3 is recorded at the head of the video and audio mixed data of the channels 2 and 3.

In this embodiment, the data of the three channels are time-division multiplexed in the order of channel 1, channel 2 and channel 3. The combined length of these three channels is slightly shorter than the uncompressed length of the signal of each channel. The reason for providing a slight time margin in this way is that it is necessary to record other various control signals when recording on the digital video disk 96.

The unit for time-division-multiplexing the video data and the audio data of each channel can be a field or a frame, but it should be a block with a predetermined period shorter than that or a predetermined period longer than that. Is also possible.

In this way, the channel multiplexer /
The data time-division-multiplexed into the digital data for one channel by the demultiplexer 91 is input to the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92, the error detection and correction code is added, and the predetermined system is further added. Is digitally modulated by. The margin described above is also used for adding the error detection and correction code.

The digital data output from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92 is
After being amplified by the RF amplifier 93, it is input to the optical pickup 94. The optical pickup 94 modulates, for example, a laser beam according to the input data, and records data corresponding to the input digital data on the digital video disk 96. At this time, the digital video disk 96 is rotated by the spindle motor 95 at a predetermined angular velocity.

On the other hand, in the reproduction mode, the optical pickup 94 reproduces the digital data recorded on the digital video disk 96 and outputs the output through the RF amplifier 93 to the ECC addition / error correction circuit and the digital modulation / decoding circuit. Output to the demodulation circuit 92. The ECC addition / error correction circuit and digital modulation / demodulation circuit 92 demodulates the input data and performs error detection / correction processing. The data subjected to such processing is further input to the channel multiplexer / demultiplexer 91. The channel multiplexer / demultiplexer 91 separates the data of channels 1 to 3 corresponding to the control signal arranged at the head of each channel shown in FIG. 2 and outputs the data to the video / audio multiplexers / demultiplexers 81 to 83, respectively. To do.

The video / audio multiplexer / demultiplexer 81 separates the input first-channel digital data into video data and audio data, and outputs them to the buffer memory 70 via the image memory controller 69 and the audio memory controller 71, respectively. It is supplied to the buffer memory 72 and stored therein. The image compression encoder / decoder 67 reads out the video data stored in the buffer memory 70 via the image memory controller 69, expands the time axis, decodes it, and D / A converts it by the D / A converter 65. Output to the output terminal 62. Further, the audio encoder / decoder 68 reads the audio data written in the buffer memory 72 via the audio memory controller 71, decodes the audio data,
D / A converter 66 performs D / A conversion, and output terminal 62
Output to.

Also in the processing circuits 52 and 53, the video / audio multiplexer / demultiplexers 82 and 8 are provided.
The same processing is executed on the data input from 3.

In the embodiment of FIG. 2, the control signal is arranged at the head of the composite signal of each channel, but the control signal is sequentially recorded at the head part of the composite signal of three channels, and thereafter. It is also possible to sequentially record the combined signal of each channel.

FIG. 3 shows a second embodiment. In this embodiment, the video signal of the first channel is A /
After the A / D conversion is performed by the D converter 63-1, the buffer memory 70-is transmitted via the image memory controller 69-1.
1 is supplied and stored. The image memory controller 69-1 also includes a buffer memory 70.
The data stored in -1 is read out and output to the D / A converter 65-1. Similarly, the second
The video signal of the channel is also A / D converted by the A / D converter 63-2, and then the image memory controller 69-
2 is supplied to the buffer memory 70-2 via the buffer 2 and stored therein. The image memory controller 69-2 also reads the data stored in the buffer memory 70-2 and outputs it to the D / A converter 65-2.

The channel multiplexer / demultiplexer 91V reads the video data read from the buffer memory 70-1 via the image memory controller 69-1 and the video data read from the buffer memory 70-2 via the image memory controller 69-2. The output video data is combined with one channel of data and output to the image compression encoder / decoder 67V. Also, the channel multiplexer / demultiplexer 9
The 1V separates the data output from the image compression encoder / decoder 67V into the video data of the first channel and the second channel, and the buffer memory 70-1 via the image memory controllers 69-1 and 69-2, respectively.
And 70-2.

The audio signal of channel 1 is A / D
After being A / D converted by the converter 64-1, the buffer memory 72-1 is passed through the audio memory controller 71-1.
It is supplied to and stored in. The data stored in the buffer memory 72-1 is read by the audio memory controller 71-1 and supplied to the D / A converter 66-1. further,
The audio signal of the second channel is the A / D converter 64.
After being A / D converted by -2, it is supplied to the buffer memory 72-2 via the audio memory controller 71-2 and stored therein. Further, the data stored in the buffer memory 72-2 is read by the audio memory controller 71-2, and the D / A converter 6
6-2 is supplied.

The channel multiplexer / demultiplexer 91A includes a buffer memory 72-1 or 7 via the audio memory controller 71-1 or 71-2.
The data read from 2-2 is combined as data for one channel and output to the audio encoder / decoder 68A.

Video / Audio Plexer / Demultiplexer 8
5 time-division-multiplexes the data input from the image compression encoder / decoder 67V and the audio encoder / decoder 68A, and converts the data into ECC for one channel.
Addition / error correction circuit and digital modulation / demodulation circuit 92
It is designed to output to. Further, the video / audio plexer / demultiplexer 85 separates the data input from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92 into video data and audio data, and the video compression encoder / decoder 67V or the audio data, respectively. It is adapted to output to the encoder / decoder 68A.

The frame synchronizer 101 causes the image memory controller 69 to read out the video data of the first and second channels that are not synchronized from the buffer memory 70-1 or 70-2 at a timing at which they can be synchronized. -1 and 69-2 are controlled. Also, so that the audio data corresponding to these video data is read at the corresponding timing,
It controls the voice memory controllers 71-1 and 71-2.

The other structure is the same as that shown in FIG.

Next, the operation will be described. In the recording mode, the video data of the first channel is A / D converted by the A / D converter 63-1 and then supplied to and stored in the buffer memory 70-1 via the image memory controller 69-1. . The video signal of the second channel is also
After being A / D converted by the A / D converter 63-2, the buffer memory 7 is passed through the image memory controller 69-2.
0-2 and stored.

Furthermore, the audio signals of the first and second channels corresponding to these video signals are also A
After being A / D converted by the A / D converter 64-1 or 64-2, the audio memory controller 71-1 or 71-
The data is supplied to the buffer memory 72-1 or 72-2 via 2 and stored therein.

The video data of the first channel and the second channel stored in the buffer memories 70-1 and 70-2 are read out in synchronization with each other by the frame synchronizer 101 and input to the channel multiplexer / demultiplexer 91V. To be done. The channel multiplexer / demultiplexer 91V time-division-multiplexes the video data of the two channels and collects the digital data of one channel. Then, the combined digital data is used as the image compression encoder / decoder 6
Input to 7V, compressed and encoded. The encoded video data is further input to the video / audio multiplexer / demultiplexer 85.

On the other hand, the buffer memories 72-1 and 72-2
The audio data of the first channel and the audio data of the second channel, which are stored in, are read out in synchronization with each other by the frame synchronizer 101, input to the channel multiplexer / demultiplexer 91A, and time-division multiplexed. The time-division multiplexed audio data is input to the audio encoder / decoder 68A, encoded, and then input to the video / audio multiplexer / demultiplexer 85.

The video / audio multiplexer / demultiplexer 85 synthesizes the video data input from the image compression encoder / decoder 67V and the audio data input from the audio encoder / decoder 68A, and 1
Output as data for channels. This data is
It is recorded on the digital video disc 96 as in the embodiment of FIG.

Further, in the reproduction mode, when the data reproduced from the digital video disk 96 is inputted to the video / audio multiplexer / demultiplexer 85 from the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92, the video / audio is transmitted. The multiplexer / demultiplexer 85 separates the input data into video data and audio data, and outputs the video data to the image compression encoder / decoder 67V and the audio data to the audio encoder / decoder 68A, respectively.

The image compression encoder / decoder 67V is
The input video data is decoded and output to the channel multiplexer / demultiplexer 91V.
Channel multiplexer / demultiplexer 91V
Separates the input video data into first channel video data and second channel video data,
Image memory controller 69-1 or 69-, respectively
It is supplied to and stored in the buffer memory 70-1 or 70-2 via 2.

The video data stored in the buffer memory 70-1 or 70-2 is supplied to the D / A converter 65-1 or 65-2 via the image memory controller 69-1 or 69-2, respectively. , D / A converted.

The audio data separated by the video / audio multiplexer / demultiplexer 85 is decoded by the audio encoder / decoder 68A, and thereafter,
Channel multiplexer / demultiplexer 91A
Entered in. The channel multiplexer / demultiplexer 91A converts the input audio data into the first audio data.
The audio memory controller 71 separates the audio data of the channel and the audio data of the second channel.
-1 or 71-2 via the buffer memory 72-1
Alternatively, they are supplied to 72-2 and stored.

The audio data stored in the buffer memory 72-1 or 72-2 is read out via the audio memory controller 71-1 or 71-2, respectively, and the D / A converter 66-1 or 66-2 is read out. By D / A
It is output after being converted.

In the embodiment shown in FIG. 1, after the video data and audio data of each channel are combined, the data of another channel is time-division multiplexed. On the other hand, in the embodiment of FIG. 3, video data or audio data of a plurality of channels are time-division multiplexed, respectively, and then encoded, and the encoded data is finally combined. There is. Since the processing time in the image compression encoder / decoder 67V and the audio encoder / decoder 68A is the longest in the processing time in each part, in the embodiment of FIG. 3, the image compression encoder / decoder 67V and the audio encoder / decoder 68A are It is preferably applied when it can be processed at high speed.

In the embodiment of FIG. 1, the data of 3 channels is recorded, and in the embodiment of FIG. 3, the data of 2 channels is recorded.
It goes without saying that the number of channels can be further increased or decreased.

In any of the embodiments, the video data and audio data are encoded by the variable length coding method. Therefore, the data amount of each channel changes depending on the content of the video signal or the audio signal.
The bit rate per unit time total amount of data recorded on the digital video disc 96 and VA _T bit / sec, the maximum writing and reading data amount of the digital video disc 96 (transfer rate) of Dbit / sec
When a, VA _T must be less than or equal to D.

Therefore, when the maximum data amount per unit time of each channel is VA _e bit / sec, the encoded data amount in the recording mode must be adjusted so as to satisfy the following equation. VA _e = D / n

Here, n is the maximum number of recording / reproducing channels.

For example, a signal having a data amount of 8 Mbps after encoding can be recorded for up to 5 channels when the transfer rate of the digital video disk 96 is 40 Mbps.

In the case of recording / reproducing a signal of a channel less than the number of recordable / reproducible channels, any one of the following three methods can be adopted.

(1) The first method is a method of recording dummy data in unused channels.

(2) The second method is a method of recording data intermittently. According to this method, the data recording capacity of the disc can be effectively used. That is, it is a method of waiting until a predetermined amount of data is accumulated, and recording the data sequentially and intermittently on the digital video disk every time the predetermined amount of data is accumulated. In this case, the reproduction is also performed intermittently, but the reproduced data is stored in the buffer memory. Then, since the data stored in the buffer memory is continuously read at a constant speed, the image can be continuously displayed.

(3) The third method is to set the disc rotation speed (angular velocity for CAV discs, linear velocity for CLV discs) to a velocity corresponding to the number of channels. That is, as the number of channels is smaller, the speed of the disc is increased, or the number of samples or the number of allocated bits per sample is increased.

The control of the speed of the disk is performed by controlling the rotation of the spindle motor 95, and
The number of data samples is controlled by the A / D converters 63 and 64.
The number of allocated bits per sample is controlled in the image compression encoder / decoder 67 and the audio encoder / decoder 68 by controlling the clock in. Alternatively, it can be controlled by the ECC addition / error correction circuit and the digital modulation / demodulation circuit 92. That is, in this embodiment, even if the number of recording channels changes, recording / reproduction is always performed at a transfer rate close to the maximum transfer rate. as a result,
When the number of channels is small, it is possible to obtain high quality images and sounds.

[0070]

As described above, according to the digital video disc of the first aspect, the video signals of a plurality of channels are compressed, time-division multiplexed and recorded on the same track. The format can be substantially the same as that of a digital video disc capable of recording only a minute video signal, and an increase in cost can be suppressed.

This makes it possible to display a plurality of screens with different viewpoints on one digital video disc. For example, a plurality of monitors can be used to display a wide or large screen image, or a plurality of screens of stereoscopic images can be displayed.

Furthermore, it becomes possible to record a video signal that requires confirmation of synchronism, such as a surveillance system using a plurality of video cameras.

According to the digital video disk device of the second aspect, the recording is performed so that the transfer bit rate of the digital video disk is close to the maximum value regardless of the number of channels of the video signal to be recorded. Because I did
It is possible to always obtain higher quality images.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of a digital video disk device of the present invention.

FIG. 2 is a diagram illustrating a relationship between time and data amount in the embodiment of FIG.

FIG. 3 is a block diagram showing a configuration of a second embodiment of a digital video disc device of the present invention.

FIG. 4 is a block diagram showing a configuration of an example of a conventional digital video disc device.

5 is a diagram illustrating a recording state in the example of FIG.

[Explanation of symbols]

51 to 53 Processing circuit 63, 64 A / D converter 65, 66 D / A converter 67 Image compression encoder / decoder 68 Audio encoder / decoder 69 Image memory controller 70 Buffer memory 71 Audio memory controller 72 Buffer memory 81 Video audio multiplexer / Demultiplexer 91 channel multiplexer / demultiplexer 92 ECC addition / error correction circuit and digital modulation /
Demodulation circuit 94 Optical pickup 95 Spindle motor 96 Digital video disk

Claims (2)

[Claims] 1. A digital video signal of a plurality of channels is compressed, a digital video signal of a plurality of channels is time-division multiplexed, and the compressed and time-division multiplexed digital video signals of a plurality of channels are recorded in the same track. A digital video disc characterized by recording. 2. A / D conversion means for A / D converting video signals of a plurality of channels, and multiplexing means for time-division multiplexing the video signals of a plurality of channels A / D converted by the A / D conversion means. Compression means for compressing the video signals of a plurality of channels A / D converted by the A / D conversion means before or after being multiplexed by the multiplexing means, and by the compression means. Recording means for recording a video signal of a plurality of channels time-division multiplexed by the multiplexing means on a digital video disc, and the transfer bit rate of the digital video disc reaches a maximum value regardless of the number of channels of the recorded video signal. A digital video disk device, comprising: a control means for controlling data so that the values become close to each other.