JPH0730849A - Data transmission equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an apparatus capable of accurately determining additional information on the receiving side. [Structure] The extraction circuit 102 extracts a pack having a pack header of "0" from the input data 101. The pack 104 whose pack header is "0" is the majority circuit 1
The contents of the pack are checked at 06, and the pack header is "
The number of packs having the same content as 0 "is counted for each content, and the pack having the largest count number in one frame is selected and output. The extraction circuit 103 outputs the input data 101.
Extract the pack whose pack header is "1" from
Check the contents of this pack in the majority decision circuit 107,
The number of packs having the same content as the pack header of "1" is counted for each content, and the pack with the largest count in one frame is selected and output. The pack header of the delay data 111 is “0” by the switching circuit 112.
And packs of "1" are packed data 108 and 10 respectively.
Replace with 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for digitally transmitting audio data and video data in a digital VTR for digitizing and recording video signals and audio signals.

[0002]

2. Description of the Related Art A conventional method of transmitting video data and audio data will be described below.

As shown in FIG. 2, the video data and audio data within one frame period of the video signal are 525 /
In the case of 60, it is divided into 10 tracks, and in 625/50, it is recorded in 12 tracks.

FIG. 3 shows an example of a digital VTR track format. Each track is ITI sector 301,
It is composed of an audio sector 302, a video sector 303, and a subcode sector 304. The audio data obtained by digitizing the audio signal and the image obtained by further compressing the video signal by digitalizing the audio data are respectively recorded in the audio sector 30.
2 and the video sector 303.

FIG. 4 shows the structure of the audio sector in each track. The audio sector is composed of 14 sync blocks each having a length of 90 bytes. Of the 14 sync blocks, 9 are audio data and additional information sync blocks for audio data, and 5 are error correction outer code parity sync blocks for the 9 blocks. Each sync block has a 2-byte sync pattern, an ID that is information for identifying each track and each sync block, 3 bytes, and data that is 77 bytes.
It is composed of 8 bytes of parity of error correction inner code for 7 bytes of data. The first 5 bytes of the 77-byte data are additional information relating to audio data recorded on the tape, such as audio signal sampling frequency information, playback speed information, and audio signal channel number information. , 72 bytes are audio data.

FIG. 5 shows the structure of a video sector. The video sector is composed of 149 sync blocks each having a length of 90 bytes. Of the 149 sync blocks, 135 are video data sync blocks, and three are recorded on tape such as video signal broadcasting system information and video signal input sources (camera, TV tuner, etc.). This is a sync block for additional information related to video data, and the remaining 11
The sync blocks are video data recorded in 135 sync blocks and sync blocks for error correction outer code parity for video additional information recorded in three sync blocks. Similar to the sync block of the audio sector, each sync block has a 2-byte sync pattern, an ID that is information for identifying each track and each sync block, 3 bytes, 77 bytes of data, and 77 bytes of data.
It is composed of the parity of the 8-byte error correction inner code for the byte data.

The additional information relating to the audio data and the video data is divided into 5 bytes called a pack and arranged in the sync block. The structure of the pack is shown in FIG. 5
The first 1 byte of the bytes is data 601 for defining the contents of a pack called a pack header, and additional information of audio data or video data is arranged in the remaining 4 bytes of pack data 602.

Since the digital VTR is digitally recorded on the tape, the information recorded on the tape can be accurately reproduced. Therefore, by transmitting the data as it is to another digital VTR and recording it, it is possible to prevent deterioration of image quality and sound quality due to dubbing. Further, when digitally transmitting a video signal and an audio signal, all the information recorded on the tape is transferred to another digital VT by multiplexing and transmitting additional information relating to those signals.
Can be duplicated to tape on R. Further, since the additional information includes information on the broadcasting system of the video signal, sampling frequency of the audio signal, and the number of channels, the additional information is multiplexed and transmitted, thereby transmitting the digital VT of the transmission destination.
In R, selection of a broadcasting system, setting of a sampling frequency of an audio signal and the number of channels can be automatically performed.

Each data is transmitted for each track on the tape and for each sync block. Each track on each transmission path transmits video data and is called a VIDEO block 1
35 transmission blocks, 3 transmission blocks called VAUX blocks for transmitting additional information of video data, 9 transmission blocks called audio blocks for transmitting audio data and additional information of audio data, and a sub-code. It is composed of two transmission blocks that are transmitted and called subcode blocks.

As shown in FIG. 7, the transmission block other than the subcode block has a length of 80 bytes, and is composed of a 3-byte ID 703 for identifying the transmission block and a 77-byte data 704. The ID3 byte 701 and the 77-byte data 702 recorded in the same sync block on the tape are transmitted in the same transmission block as the ID 703 and the data 704. Therefore, since the additional information regarding the audio data is recorded in the same sync block as the audio data, it is transmitted in the same AUDIO block as the audio data. Further, since the additional information relating to the video data is recorded by being divided into three sync blocks, it is transmitted by three VAUX blocks when digitally transmitted.

The additional information of the video data includes information such as the broadcasting system of the reproduced video data, and the additional information of the audio data includes the sampling frequency when the audio signal is sampled and the number of channels of the audio signal. Contains information. When dubbing with another VTR, the VTR on the receiving side uses these pieces of information to select the broadcasting system of the video signal and set the sampling frequency and the number of channels of the audio signal. This is very important information for a digital VTR. If these cannot be reproduced due to an error, the VT on the receiving side
It becomes impossible to select the broadcasting system of the video signal and set the sampling frequency and the number of channels of the audio signal in R. A pack containing such important additional information is recorded on the tape a plurality of times within one frame period. Therefore, the same pack is reproduced a plurality of times within one frame of the video signal unless erroneous correction occurs.

[0012]

According to the above method, when the reproduction state is bad, the probability of erroneous correction due to error correction increases. As for the erroneously corrected data, it can no longer be detected that there is an error, and therefore the erroneous data is transmitted as it is. Especially when the outer code error correction cannot be performed, as in the case of high speed reproduction,
In particular, the probability of erroneous correction increases. In the conventional example described above,
Since all the additional information is transmitted as recorded on the track, the pack containing the important information recorded multiple times in one frame is transmitted multiple times in one frame. Originally, if the pack header is the same in one frame, exactly the same data should be reproduced in the pack that is reproduced a plurality of times. When the pack containing the important information is error-corrected due to the occurrence, since the pack data having different contents is reproduced within one frame even though the pack header is the same, the reception is performed. The side cannot determine which additional information should be followed.

Therefore, there is a problem that the receiving deck cannot select the broadcasting system for the video signal and set the sampling frequency and the number of channels for the audio signal based on the additional information transmitted.

[0014]

In order to solve the above problems, the present invention digitally transmits video data in which a video signal is digitized and further compressed, and audio data in which an audio signal is digitized. A transmission device for transmitting, together with data, additional information relating to the video data and the audio data a plurality of times within one frame period of the video signal, the content of the additional information transmitted within one frame period of the video signal. Is uniformly transmitted within one frame.

[0015]

According to the present invention, with respect to important additional information in which additional information having the same content is recorded a plurality of times on the tape within one frame period, additional information having different content is reproduced in one frame due to erroneous correction or the like. In this case, the additional information having different contents is unified and transmitted to the contents considered to be the most accurate. As a result, since the receiving side can obtain the additional information having the same content, it becomes possible to set the digital VTR based on the additional information.

[0016]

1 is a block diagram of a transmission apparatus according to an embodiment of the present invention. The following is a description of a case where important information such as the broadcasting system of the video signal, the sampling frequency of the audio signal, and the number of channels is recorded in two packs of "0" and "1" in the pack header. In this embodiment, two types of packs having pack headers of "0" and "1" are transmitted a plurality of times within one frame. When transmitting multiple times, the contents of the pack are unified to the contents that seem to be the most accurate.

The input data 101 is reproduced data, which is data corrected by an error correction circuit. The pack 0 extraction circuit 102 uses the input data 10
A pack whose pack header is "0" is extracted from 1. The pack 104 with the pack header “0” extracted by the pack 0 extraction circuit 102 is input to the majority decision circuit 106. The majority decision circuit 106 checks the contents of the pack having the pack header of "0", counts the number of packs having the pack header of "0" and the same contents for each content, and counts the largest number in one frame. Select the pack and output. The pack 1 extraction circuit 103 uses the input data 101
The pack whose pack header is "1" is extracted from the list. The pack 105 whose pack header is “1” extracted by the pack 1 extraction circuit 103 is input to the majority decision circuit 107. The majority decision circuit 107 checks the contents of the pack whose pack header is "1", counts the number of packs whose pack header is "1" and has the same contents by contents, and determines the pack with the largest count in one frame. To output. The output packs 108 and 109 are packs output from the majority decision circuits 106 and 107, respectively.

The input data 101 is delayed by one frame by the delay circuit 110. Therefore, the delay data 11
1 is data obtained by delaying the input data 101 by one frame by the delay circuit 110. The pack header of the delay data 111 is “0” by the switching circuit 112.
And packs of "1" are packed data 108 and 10 respectively.
Replace with 9. By doing so, the output data 113 will have the packs with pack headers "0" and "1" unified and output with the contents that are most likely to be accurate.

In this embodiment, the number of packs whose contents are unified in one frame is two, but it is also possible to increase the number of packs whose contents are unified by increasing the number of majority voting circuits. is there.

In the audio signal, for example, when two-channel audio signals are recorded, each channel can be independently edited. Therefore, additional information can be independently edited on the tape. become. Therefore,
The additional information relating to the audio data is transmitted by unifying the contents in one frame for each independently editable unit on the tape.

[0021]

As described above, according to the present invention, a pack in which the same data is transmitted a plurality of times within one frame period when an erroneous correction occurs in the error correction, which has been a problem in the conventional example. Since the packs having different contents are transmitted, it becomes possible to select the broadcasting system of the video signal and set the sampling frequency and the number of channels of the audio signal by the digital VTR on the receiving side.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a data transmission device of the present invention.

FIG. 2 is a diagram showing an example of a recording pattern of a digital VTR.

FIG. 3 is a diagram showing an example of a track format of a digital VTR.

FIG. 4 is a diagram showing an example of a configuration of a voice sector of a digital VTR.

FIG. 5 is a diagram showing an example of a configuration of a video sector of a digital VTR.

FIG. 6 is a diagram showing an example of the structure of a pack for recording additional information of a digital VTR.

FIG. 7 is a diagram showing a transmission method of a digital VTR.

[Explanation of symbols]

 101 input data 102 pack 0 extraction circuit 103 pack 1 extraction circuit 104 pack header 0 pack 105 pack header 1 pack 106 majority circuit 107 majority circuit 108 most accurate pack header 0 pack 109 most accurate pack header is 1 pack 110 delay circuit 111 delay data 112 switching circuit 113 output data

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area H04L 1/00 F 9371-5K H04N 7/08 7/081 6942-5C H04N 7/08 Z

Claims (2)

[Claims] 1. Video data obtained by digitizing a video signal,
And a transmission device for digitally transmitting audio data obtained by digitizing an audio signal, and transmitting the video data and the audio data together with additional information about the video data and the audio data a plurality of times within one frame period of the video signal. The data transmission device is characterized in that the contents of the additional information transmitted within one frame period of the video signal are unified and transmitted within one frame. 2. Regarding the additional information relating to the audio data,
The data transmission apparatus according to claim 1, wherein the contents are unified and transmitted within one frame period for each editable unit.