JP2734335B2 - Data transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting data with a digital signal applied to a digital VTR or the like.

[0002]

2. Description of the Related Art At present, various companies are studying digital VTRs for recording and reproducing video and audio signals as digital signals. The digital VTR is characterized in that, by transmitting data as a digital signal, even when dubbing from one digital VTR to another digital VTR, image quality and sound quality do not deteriorate. In addition, by transmitting the digitized audio signal and video signal in a time-division multiplex manner and transmitting them, a single transmission path can be obtained.

FIG. 6 shows a method of transmitting a video signal and an audio signal of a digital VTR commercialized for business use as digital signals. In the digitized video signal, one sample is quantized by 10 bits, and the digitized video signal including the composite sync is transmitted as it is. The digitized audio signal and additional information are multiplexed and transmitted to a portion corresponding to the bottom of the composite sync of the video signal. The receiving digital VTR detects a data string of sample values corresponding to the composite sync, and recognizes each data of the video signal and the audio signal.

[0004]

According to the transmission method shown in the conventional example, since the sample values of the video signal and the audio signal are transmitted as they are, the transmission rate is 100 MHz or more. The use of such a transmission line corresponding to 100 MHz or higher has a problem that the cost is too high, especially for consumer use.

In a digital VTR for consumer use, a video signal is compressed and recorded in order to reduce the tape consumption. Therefore, when transmitting to another digital VTR, the transmission rate is kept low by transmitting the video signal in a compressed state. It becomes possible. However, in the transmission method in the conventional example, each data of the video signal and the audio signal is recognized by detecting a data sequence of a sample value of a synchronization signal portion of the video signal, and the compressed video signal data is Does not include the sample value of the synchronization signal, and thus has a problem that the data of the video signal cannot be transmitted in a compressed state.

[0006]

According to the present invention, the following method is newly proposed as means for solving the above-mentioned problems.

That is, the present invention is a method of digitally transmitting audio data and video data, wherein the audio data is divided into n blocks each having m bytes, and one block of video data is composed of m bytes. 15x
The data transmission method is characterized in that the data is divided into n blocks, and 16 blocks each composed of one block of audio data and 15 blocks of video data are divided into one group and transmitted in units of the group.

[0008]

According to the present invention, audio data and compressed video data are divided into a plurality of blocks, and a total of 16 blocks of one audio data block and 15 compressed video data blocks are grouped into one group. By adding the synchronization code word, audio data and video data can be recognized.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

[0010] In a digital VTR for consumer use, it is necessary to keep the transmission rate low, and therefore, it is necessary to transmit the video signal in a compressed state. FIG. 3 shows an example of a tape format of a digital VTR using this embodiment. I
The TI area 301 is an area for recording information for accurately performing insertion. The INDEX area 302 is an area for recording information such as a time code. AUDI
An O area 303 is an area for recording an audio signal, and a VIDEO area 304 is an area for recording a video signal. Also GAP
The area 305 is an INDEX area 302 and an AUDIO area 3
03 and VIDEO area 304 are margin areas for recording independently.

[0011] The video and audio signals for one frame period of the video signal are recorded on the ten tracks having this configuration. The video signal is compressed so that the ratio between the audio data and the video data becomes 1:15 so that the video data can be transmitted by the method of the present embodiment.

FIG. 4 shows the configuration of the AUDIO area 303. The audio data includes digitized data of an audio signal and additional audio information such as a sampling frequency. AU
The DIO area 303 is composed of 14 synchronization blocks having a length of 90 bytes. Nine of the 14 synchronization blocks are synchronization blocks for audio data, and 5 are synchronization blocks for error-correcting outer code parity for the nine blocks. Each synchronous block has a 2-byte synchronous pattern, an ID for identifying each track and each synchronous block of 3 bytes, and audio data of 7 bytes.
It is composed of 7 bytes and parity of an 8-byte error correction inner code for 77-byte data.

FIG. 5 shows the structure of the VIDEO area 304. The amount of video data is 1 of the amount of audio data
This is a video signal compressed so as to be five times as large. VIDE
The O area 304 is composed of 149 synchronization blocks having a length of 90 bytes. 1 out of 149 synchronization blocks
Thirty-five are synchronous blocks for video data, three are synchronous blocks for additional video information such as teletext data, and the remaining eleven synchronous blocks are recorded in 135 synchronous blocks. This is a synchronous block for error correction outer code parity for video data and video additional information recorded in three synchronous blocks. Each sync block has a 2-byte sync pattern, a 3 byte ID which is information for identifying each track and each block, 77 bytes of video data, and 77 bytes of data, similar to the sync block in the AUDIO area. And the parity of an 8-byte error-correcting inner code.

When digitally transmitting data to another VTR by the transmission method of the present embodiment, the data to be transmitted is composed of 77 bytes of audio data or video data in each of the synchronous blocks, and data in the INDEX area 302. This is AUX data including video additional information. In this digital VTR, audio data is divided into nine synchronous blocks in each track, and video data is divided into 135 synchronous blocks. That is, the ratio of the data amounts of the audio data and the video data is 1:15. In this embodiment, when data is transmitted to another digital VTR, 77 bytes of data recorded in one synchronization block are regarded as one block, and a total of 16 blocks of 1 block of audio data and 15 blocks of video data are used. Data is transmitted as a group in units of groups. Nine blocks are needed to transmit one track of audio data and video data. Also, since one frame is composed of ten tracks, 90 groups are required to transmit audio data and video data within one frame period. Also, 1
The AUX data within the frame period is divided into 32 blocks, each of which has 77 bytes in length as one block.
The blocks are grouped into one group and transmitted in two groups.

FIG. 1 shows a data transmission method according to this embodiment.
Video data and audio data within one frame period of a video signal are transmitted in two video / audio data transmission areas 101.
Each video / audio transmission area 101 is composed of 45 groups 103. AUX data within one frame period is AUX
The data is transmitted in the data transmission area 102. The AUX data transmission area 102 is composed of two groups. Each group in the video / audio transmission area 101 indicates the boundary of each group.
A byte synchronization code word 106 and a group number 107 indicating a group number from the beginning of the frame are added to identify each group in the frame. Each group of the video / audio transmission area is composed of one audio data block 10.
It is composed of 4 and 15 blocks 105 of video data. In this embodiment, audio data is transmitted in the first block in each group. Each block has a block number 108 for identifying each block in the group.
It consists of bytes, 77-byte data 109 and error correction parity 110. In the data 109, the first block in each group is audio data, and the other blocks are video data. In the present invention, since one group is composed of 16 groups, the number of blocks is counted from the beginning of the frame, and the lower 4 bits of the count number are the block number and the upper bits are the group number. .

FIG. 2 shows an example of a block diagram of a circuit for transmitting data to another digital VTR with the data structure of the present embodiment. Video data 201, audio data 202, and AUX data 203 are input to the selection circuit 204. The selection circuit 204 selects and outputs the data 205 input to the error correction parity generation circuit 206 and the selection circuit 213. The parity generation circuit 206 generates an 8-byte parity 207 every 77 bytes in the data 205 input from the selection circuit 204. The synchronization codeword generation circuit 208 outputs a synchronization codeword 209 at the head of each group. The block number counter 210 is initialized to 0 at the beginning of a frame, and counts up at the beginning of each block. The output of the block number counter is 11 bits, of which the lower 4 bits are the block number 21 added to each block.
1 and the other upper 7 bits are the group number 21
2. The selection circuit 213 includes a synchronization codeword 209, a group number 212, a block number 211, each data 205 output from the selection circuit 204, and a parity 2 for error correction.
07 is selected and output.

The receiving side detects a synchronization codeword added to the head of each group, detects a group number and a block number from the detected synchronization codeword, and recognizes data of each block. As described above, by transmitting data as in this embodiment, it is possible to transmit a video signal while being compressed.

Although the present embodiment has been described with respect to video signals and audio signals, for general data handled by a computer or the like, one block is composed of 77 bytes and 16 blocks constitute one group. Needless to say, it is possible to transmit the data.

[0019]

As described above, according to the present invention, audio data and compressed video data are divided into a plurality of blocks,
By combining a total of 16 blocks of one block of audio data and 15 blocks of compressed video data into one group, and adding a synchronization codeword to the head of each group, it is possible to recognize the voice data and the video data. Further, by forming each group with 16 blocks, there is an effect that both the group number and the block number can be generated only by the block number counter.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of each data for realizing a transmission method of the present invention.

FIG. 2 is a block diagram showing an example of a circuit for realizing the transmission method of the present invention.

FIG. 3 is a diagram showing an example of a track format of a digital VTR using the transmission method of the present invention.

FIG. 4 is a configuration diagram of an AUDIO area of a track format of a digital VTR using the transmission method of the present invention.

FIG. 5 is a configuration diagram of a VIDEO area of a track format of a digital VTR using the transmission method of the present invention.

FIG. 6 is a diagram showing a conventional transmission method.

[Explanation of symbols]

 Reference Signs List 101 video / audio data transmission area 102 AUX data transmission area 103 group constituting video / audio data area 104 block for transmitting audio data 105 block for transmitting video data 106 synchronization codeword 107 group number 108 block number 109 data 110 parity

Claims (1)

(57) [Claims] 1. A method for digitally transmitting audio data and video data, comprising dividing audio data into n blocks each having m bytes, and dividing the video data into 15 × n blocks each having m bytes. A data transmission method, wherein the data is divided into a plurality of blocks, and 16 blocks each composed of one block of audio data and 15 blocks of video data are grouped into one group and transmitted in units of the group.