JPH10200921A - Digital data transmission method, data recording / reproducing device, data editing device - Google Patents

Abstract

(57) [Problem] To provide a digital data transmission method, a data recording / reproducing device, and a data editing device having compatibility between video data having different compression formats. Kind Code: A1 A compression coding is performed by adding a color (C) signal of a video signal input from an input terminal to a luminance (Y) signal of a video signal input from an input terminal.
One compressed video data (base data) is generated. The input video signal is up-converted to generate a 4: 2: 2 compressed video signal, and the subtraction circuit 123 obtains a difference from the base data. This difference is compression-encoded to generate enhancement data. 4: 1:
When transmitting 1 video data, only the base data is transmitted, and when transmitting 4: 2: 2 video data, enhancement data is added to the base data and transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data transmission method for compressing and transmitting digital video data, and
The present invention relates to a data recording / reproducing device for recording / reproducing digital video data and a data editing device for editing digital video data.

[0002]

2. Description of the Related Art A video such as a television broadcast program is usually produced by editing material data recorded on a magnetic tape. The editing work is divided into online editing in which editing is performed using a high-quality material tape for broadcasting, and offline editing in which copying is performed on an editing tape and rough editing is performed. Normally, offline editing is performed without using valuable material tapes.

In recent years, as an editing device used for editing work, a digital editing device based on a personal computer or the like has become widespread. The digital editing device includes a storage device using a hard disk or the like for storing video data and a digital image processing device, and stores video data required for editing in a digital video tape recorder (digital VT).
After transfer from R) to the hard disk, editing work can be performed at a timing independent of the external device. Such an editing method is called non-linear editing.

[0004] As described above, a digital video tape recorder (VTR) is connected to a non-linear editing apparatus used for non-linear editing, and digital video data is transferred between them. This digital VTR has several types of formats, for example, the D1 standard for program production and the D2 standard for broadcast stations are typical.

[0005] In such a digital VTR for business use, since the image to be recorded and reproduced is required to be of extremely high quality, the video data recorded on the magnetic tape is not compressed or about 1/2. Is usually a relatively low compression ratio.

[0006] On the other hand, digital VTRs have begun to spread for home use. Home digital VTRs are less demanding on image quality than digital VTRs for business use, but are required to be able to record for a long time using a small cassette tape.
A compression format for recording by band compression at a relatively high compression ratio of / 5 is adopted. The high-efficiency compression method used here utilizes the fact that human visual characteristics are less sensitive to chrominance information than video luminance information, and reduces the amount of information of chrominance signals. ing. The method of compressing the video data will be described later.

In the D1 standard, which is one of the above-mentioned digital VTR standards for business use, digital video data recorded on a magnetic tape is not compressed, and a luminance signal Y and a chrominance signal Cr are not compressed.
And Cb are individually recorded. The luminance signal Y is a signal representing the brightness of the video, and the color difference signal is a signal representing the chromaticity of the video. The color difference signal is a signal obtained by removing the luminance signal Y from the three primary color signals of R, G, and B, and Cr = R−
Two of Y and Cb = BY are used. The sampling frequency of the luminance signal Y is 13.5 MHz, and the sampling frequencies of the color difference signals Cb and Cr are 6.75 MH, respectively.
z. Therefore, the ratio of the sampling frequencies of these signals is 4: 2: 2.

On the other hand, if the above-mentioned video data of the home digital VTR standard is similarly expressed, the luminance signal Y
And the sampling frequency ratio of the color difference signals Cb and Cr is
It is expressed as 4: 1: 1. That is, by reducing the sampling frequency of the two color difference signals to half the sampling frequency of the luminance signal, the information amount of video data recorded on the magnetic tape is reduced.

[0009]

As described above, different video data compression methods are used for digital VTRs. However, in the conventional non-linear editing apparatus, the compression method (format) of video data transferred to and from a digital VTR is fixed, and none of them can support a plurality of data compression formats.

For this reason, for example, when editing the above-mentioned 4: 1: 1 compressed video data and 4: 2: 2 compressed video data, either one of the compressed video data is decompressed and then edited. Work has to be performed, and it is inevitable that image deterioration occurs when the edited video data is compressed again.

The present invention has been made to solve this problem, and provides a digital data transmission method, a data recording / reproducing apparatus, and a data editing apparatus which ensure compatibility between video data having different compression formats. The purpose is to do.

[0012]

According to the digital data transmission method of the present invention proposed to solve the above problem, the ratio of the sampling frequency of the luminance signal to the sampling frequency of the two color difference signals is 4: 1: 1. Basic video data,
Alternatively, there is provided a digital data transmission method for transmitting extended video data in which a ratio between a sampling frequency of a luminance signal and a sampling frequency of two color difference signals is 4: 2: 2,
The transmission data of the extended video data is configured by adding enhancement data obtained by compressing and encoding a difference between the extended video data and the basic video data to base data obtained by compressing and encoding the basic video data. It is characterized by being performed.

According to this digital data transmission method, the base data and the enhancement data are compressed and decompressed and decoded, respectively.
Compatibility between 1: 1 video data and 4: 2: 2 video data can be obtained.

Further, the data recording / reproducing apparatus of the present invention compresses and encodes video data to generate basic video data in which a sampling frequency ratio between a luminance signal and two color difference signals is 4: 1: 1. Compression encoding means for generating enhancement data by calculating a difference between the extended video data having a ratio of the sampling frequency of the luminance signal to the sampling frequency of the two color difference signals of 4: 2: 2 and the basic video data. Compression encoding means, recording and reproducing means for recording the compression-encoded video data on a recording medium, and reproducing the video data from the recording medium; and expanding and decoding the reproduced video data, It is characterized by comprising a first decompression decoding means for obtaining basic video data and a second decompression decoding means for generating the extended video data.

According to the data recording / reproducing apparatus, 4:
Both 1: 1 video data and 4: 2: 2 video data can be recorded / reproduced.

Further, the data editing apparatus of the present invention compresses and encodes video data to generate basic video data in which a sampling frequency ratio between a luminance signal and two color difference signals is 4: 1: 1. Encoding means for generating enhancement data by calculating a difference between the extended video data and the basic video data, wherein the ratio of the sampling frequency of the luminance signal to the sampling frequency of the two color difference signals is 4: 2: 2. Compression encoding means, first decoding means for decompressing and decoding the basic video data, second decoding means for decompressing and decoding the enhancement data, and a recording medium for storing the basic video data and the enhancement data. Recording and reproducing means for recording the basic video data and the enhancement data from a recording medium, It is characterized in further comprising a bus for transferring fine additional data.

According to this data editing apparatus, both 4: 1: 1 video data and 4: 2: 2 video data can be transferred to and from a connected digital VTR or the like. 1: 1 video data and 4: 2: 2 video data can be edited as compressed video data,
It is possible to prevent the image quality of the edited video from deteriorating due to the repeated expansion / compression.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a digital data transmission method, a data recording / reproducing apparatus and a data editing apparatus according to the present invention will be described below with reference to the drawings. Here, first, a compression encoding circuit and a decompression decoding circuit applied to the data recording / reproducing apparatus and the data editing apparatus will be described, and a digital data transmission method of the present invention will be described with reference to these configurations. Next, a data recording / reproducing apparatus and a data editing apparatus according to the present invention to which this digital data transmission system is applied will be described.

FIG. 1 is a block diagram showing a configuration of a compression encoding circuit to which the digital data transmission method of the present invention is applied. This compression encoding circuit is used in a data editing device and a data recording / reproducing device of the present invention, which will be described later. The compression encoding circuit compresses and encodes input video data to generate a luminance signal Y and two color difference signals Cr and Cb. Base data obtained by compressing and encoding basic video data having a sampling frequency ratio of 4: 1: 1, and enhancement data added to the base data to form extended video data having a sampling frequency ratio of 4: 2: 2. Generate

The luminance signal Y of the video data input from the input terminal 110 is supplied to the blocking unit 111.
The blocking unit 111 has an input terminal 120.
Is also supplied via a low-pass filter (LPF) 117. Then, the luminance signal Y is divided into blocks so that the sampling frequency ratio of the two color difference signals Cr and Cb of the color signal C becomes 4: 1: 1.

In this blocking, one frame of video data is divided into (8 × 8) pixel blocks each represented by 8 bits. Each divided block is
It is called a macroblock, and is a basic unit when performing discrete cosine transform (DCT) described later. In each macro block, one block of each of the color difference signals Cr and Cb is arranged for each of the four blocks of the luminance signal Y.

The macro block is shuffled by being selected from each of five different areas on the video screen in order to improve the compression efficiency of the video data.

In the DCT section 112, the blocking section 11
DCT (discrete cosine transform), which is a type of orthogonal transform, is performed on the video data (macroblock) divided into blocks. Further, the pixel values of the video data are decorrelated and converted to values on the frequency axis. At this time, the macro block has a fixed block length.

Video data in which all macroblocks have been subjected to discrete cosine transform are temporarily stored in a buffer (not shown) and sent to the quantization unit 113.

The quantization unit 113 divides the DCT coefficient by a certain divisor (quantization step) for each macroblock, rounds the remainder, and performs quantization. At this time, adaptive quantization using different quantization steps is performed in consideration of human visual characteristics. The visual characteristics considered here are, for example, such that a portion having high precision on a video screen does not have a noticeable quantization distortion even when coarsely quantized, and a portion that changes smoothly has a conspicuous quantization distortion. .

The above-described adaptive quantization is performed by classifying each block in a segment of video data into four types and assigning different quantization steps constituting a quantizer according to class numbers. As a result, it is possible to improve the image quality by increasing the number of bits allocated to blocks of a portion with low precision on the screen. The video data (DCT coefficients) quantized in this way is sent to the two-dimensional Huffman encoding unit 114 and the inverse quantization unit 118.

The two-dimensional Huffman coding unit 114 performs two-dimensional Huffman coding, which is variable-length coding. That is, based on the data amount estimation, the quantizer number (QNo.)
Is selected, the video data segment stored in the buffer is quantized by the quantizer number, and then is subjected to variable-length coding.

This variable-length coding is called two-dimensional Huffman coding. The matrix of each quantized DCT coefficient is zigzag-scanned to one dimension, and the length (DCT coefficient) is continuously zero. A code prepared on a table in advance is assigned to the (run length) and the subsequent set of non-zero coefficient values. Here, the encoding is performed such that the data amount for each of the five macroblocks is equal to each other.

The framing unit 115 performs a process called framing, in which each segment of the video data that has been variable-length coded by the two-dimensional Huffman coding unit 114 is allocated to 77 bytes. Here, of the five macroblocks described above, for a macroblock having a data amount exceeding 77 bytes, the overflowed data is allocated to a free area of another macroblock and packed. As a result, the basic video data (base data) in which the data amount of each macroblock is equal and the ratio of the sampling frequency of the luminance signal Y to the sampling frequency of the two color difference signals Cr and Cb is 4: 1: 1 is output to the output terminal 116. From 25Mbps
Output at the rate

On the other hand, the color signal C of the video signal input from the input terminal 120 is supplied to the blocking section 121, and the blocking section 121 is divided into blocks so that the sampling frequency ratio of the two color difference signals Cr and Cb becomes 2: 2. Is done.

The procedure of blocking is the same as that of the above-described blocking section 111, and divides one frame of video data into macroblocks of (8 × 8) pixels represented by 8 bits. is there.

The low-pass filter (LPF) 117 is provided to extract only two color difference signals Cr and Cb from the color signal C input from the input terminal 120, and outputs the same to the blocking unit 111. Supplied.

The selector (SEL) 122 includes video data that has been blocked by the blocking unit 111 so that the sampling frequency ratio of the luminance signal Y and the two color difference signals C is 4: 1: 1. A color signal C which is blocked so that the sampling frequency ratio of the two color difference signals Cr and Cb is 2: 2 is supplied.
Then, the Y signal and the C signal are selected at a predetermined timing. Specifically, only the Y signal is selected and output from the 4: 1: 1 video data supplied from the blocking unit 111, and the C signal from the blocking unit 121 is output as it is. Then, the above selected output is sent to the subtraction circuit 123.

In the inverse quantization unit 118, the quantization unit 1
The 4: 1: 1 video data quantized in step 13 is inversely quantized and supplied to the inverse DCT unit 119.

In the inverse DCT unit 119, the inverse quantization unit 118
Inverse DCT to 4: 1: 1 video data inversely quantized by
(Inverse discrete cosine transform), and supplies the result to the subtraction circuit 123.

In the subtraction circuit 123, a selector (SEL)
An operation (A-B) of subtracting the output (B) of the inverse DCT unit 119 from the output (A) of 122 is performed.

The calculation result (A-B) is composed of video data A having a sampling frequency ratio of 4: 2: 2 between the luminance signal Y and the two color difference signals Cr and Cb, and video data A having a sampling frequency ratio of 4: 1: 1. B, which is video data mainly including high-frequency components necessary for expressing details of the video.

Since the sampling frequency of the color difference signal of the video data B supplied from the inverse DCT section 119 is half the sampling frequency of the color difference signal of the video data A, the sampling frequency of both of them is calculated by the subtraction circuit 123. The frequencies must be equal. Therefore, the video data B is supplied to the subtraction circuit 123 after the sampling frequency is doubled (up-converted).

The enhancement data encoding unit 124 encodes the output of the subtraction circuit 123, that is, the difference between the video data having a sampling frequency ratio of 4: 2: 2 and the video data having a sampling frequency ratio of 4: 1: 1. Here, the aforementioned DCT
(Discrete cosine transform), subband coding, or the like can be used as the coding method.

The framing unit 125 performs the above-described framing process on the difference between the video data encoded by the enhancement data encoding unit 124 and outputs the data as enhancement data from the output terminal 126 at a rate of 25 Mbps. .

This enhancement data is video data centered on the high-frequency component of the luminance signal Y, which is not included in the base data having a sampling frequency ratio of 4: 1: 1. By adding this enhancement data to the base data, a digital VT for business use can be obtained.
High-definition video data corresponding to 4: 2: 2 video data used for R and the like can be obtained. This will be described later.

FIG. 2 is a block diagram showing a configuration of a decompression decoding circuit according to the present invention. This decompression decoding circuit is a decompression decoding circuit corresponding to the compression encoding circuit of FIG. 1, and decompresses and decodes the above-described base data and enhancement data, which are compression-encoded and recorded on a magnetic tape or the like. And regenerate it.

The input terminal 130 receives the above-described base data having the sampling frequency ratio of 4: 1: 1, and the input terminal 140 receives the enhancement data. The rate of each of these data is 25 Mbps
It is.

The input base data and enhancement data are sequentially subjected to deframing, two-dimensional Huffman decoding, inverse quantization, and inverse discrete cosine transform. Then, both data are added to adders 135 and 14
The signals are added to each other at 5, and each added output is deblocked and output as a Y signal and a C signal.

In the deframing section 131, the input terminal 1
The base data input from 30 is subjected to a process called deframing, which is the reverse operation of the framing process described above. That is, video data that has been packed so that the data amount becomes equal for each of the five macroblocks is returned to video data that has been subjected to variable-length encoding for each macroblock. On the other hand, the deframing unit 141 performs the above-described deframing process on the enhancement data input from the input terminal 140, similarly to the deframing unit 131.

Two-dimensional Huffman decoding units 132 and 14
Reference numeral 2 denotes an inverse transform of the transform performed by the two-dimensional Huffman encoding unit 114 of the compression encoding circuit shown in FIG.
For base data and enhancement data,
Each performs two-dimensional Huffman decoding.

The inverse quantization units 133 and 143 are portions corresponding to the quantization unit 113 in the compression encoding circuit of FIG. 1, and perform operations opposite to the quantization. That is, each DCT coefficient is multiplied by a quantization step for each macroblock of (8 × 8) pixels described above.

Inverse DCT (Inverse Discrete Cosine Transform) section 134
And 144, an inverse discrete cosine transform (inverse DCT), which is the inverse of the discrete cosine transform (DCT), is performed for each inversely quantized macroblock.

The output of the inverse DCT unit 134 is sent to a Y signal adder 135 and a C signal adder 145. On the other hand, the output of inverse DCT section 144 is sent to C signal adder 145 and Y signal adder 135.

The two-dimensional Huffman decoding unit 142, the inverse quantization unit 143, and the inverse DCT unit 144 correspond to the extension data decoding circuit shown in FIG. In part 124,
This is a configuration example in the case where compression encoding is performed by DCT.

In the luminance (Y) signal adder 135 and the color (C) signal adder 145, the base data and the enhancement data subjected to the above-described signal processing are added to each other. Since the sampling frequency of the chrominance signal of the base data supplied from the inverse DCT unit 134 is half the sampling frequency of the chrominance signal of the enhancement data, the two sampling frequencies must be equal to be added by the C signal adder 145. Must. Therefore, the two color difference signals Cr and Cb of the base data
Are supplied to the C signal adder 145 after the sampling frequency is doubled (up-converted).

The deblocking units 136 and 146
The base data and the enhancement data added to each other by the Y signal adder 135 and the C signal adder 145 are
Each of them performs a deblocking process. This deblocking process is a reverse operation of the blocking process in the compression encoding circuit of FIG. 1, and is a process of reconstructing one frame of video data divided into macroblocks of (8 × 8) pixels.

The base data deblocked by the deblocking unit 136 is output from the output terminal 137 as a Y signal, and the enhancement data deblocked by the deblocking unit 146 is output from the output terminal 147 as a C signal.

According to the digital data transmission method of the present invention, the basic video data in which the ratio of the sampling frequency of the luminance signal Y to the two color difference signals Cr and Cb is 4: 1: 1 and the ratio of the sampling frequency of 4: This is a digital data transmission method compatible with 2: 2 high definition extended video data.

More specifically, FIG. 1 and FIG.
As shown in FIG. 3A, digital video data transmitted via the compression encoding circuit and the decompression decoding circuit
25 Mb obtained by compressing and encoding 4: 1: 1 basic video data
It is configured by adding 25 Mbps enhancement data to ps base data.

According to such a configuration, when the basic video data of 4: 1: 1 is transferred, only the base data needs to be transferred, and a higher definition video can be obtained.
When the extended video data is transferred, enhancement data mainly including high-frequency components can be added to the base data to substantially constitute 4: 2: 2 video data.

FIG. 3B is a diagram showing a 4: 1: 1 video data and a 4: 2: 2 in the digital data transmission method of the present invention.
2 shows an interface for transferring video data with other video data. In this case, a 270 Mbps serial data interface is used.

FIG. 3C shows an interface for transferring 4: 2: 2 video data in the digital data transmission method of the present invention. In this case, a 360 Mbps serial data interface is used.

Next, 4: 1: 1 compressed video data, which is used as base data in the digital data transmission method of the present invention, will be specifically described with reference to FIGS. This format can also transmit uncompressed original video data, audio data, control information, and the like.

FIG. 4 shows compressed video data of a plurality of channels in each time slot obtained by dividing a transmission unit having a length equal to a period forming one horizontal line (scanning line) defined by a predetermined analog video signal standard into a plurality of time slots. This shows how data is arranged.

As shown in FIG. 4A, an EAV (end of active video) area 60 is provided prior to an area where video data is arranged. Subsequent to the EAV area 60, an auxiliary signal area 61 is provided. Auxiliary signal area 61
Next, a SAV (start of active video) area 62 is provided. SAV and EAV are 1
It is composed of each word of (3FF, 000,000,000,000, XYZ) h of a hexadecimal signal. The EAV area 60, the auxiliary signal area 61 and the SAV area 62 have a scanning line number of 525.
In the 50 lines / 60-field system, 276 words (Words) are used.
It consists of 88 words.

After the SAV area 62, an area including the video data shown in FIG. 4B is provided. In this data area, digital video data obtained by encoding a video signal with high efficiency is arranged. A 6-word data header area including a separator (start code) 66, a type 67, and a word 68 is provided at the leading end of this area. In addition,
This data header area is provided only on the twelfth line in the 525-line / 60-field system, and is provided on the eighth line in the 625-line / 50-field system. Subsequent to the area in which the data header is provided, a header area consisting of 10 words indicating the interface of this transmission system is provided. The interface header area includes one-word information 69 indicating a data transfer speed and a nine-word reserve area 70 in which status information such as a VTR can be written as a format. Following the interface header area, five data areas 63a to 63e each consisting of 280 clocks (Clocks).
And a reserved area 64 of 22 words. The header area from the start code 66 to the reserve area 70 and an area including the data areas 63a to 63e and the reserve area 64 are called a payload area. Each of the data areas 63a to 63e has 256 bytes (Bytes).
And a reserve area consisting of 24 bytes.

Next to the payload area, a 2-word CR is used.
C region 65 is provided. The CRC area 65 is composed of CRCC (cyclic redundancy check code) 0 and CRCC1 areas (not shown). In addition, this CR
CC0 and CRCC1 are as follows. That is, the information frame to be transmitted is transmitted after adding a remainder term obtained as a result of performing a certain division. The receiving end checks a transmission error by matching a remainder term obtained by performing the same operation on the received signal with the transmitted remainder term. For this division, a generator polynomial is used.

The payload area and the CRC area 65 are
Both the video signal standard of 525 scanning lines / 60 fields and the video signal standard of 625 scanning lines / 50 fields consist of 1440 words. Therefore, EAV
In the region 60, the auxiliary signal region 61 and the SAV region 62,
The area including the payload area and the CRCC0 and CRCC1 areas is composed of 1716 words in the video signal standard of 525 scanning lines / 60 fields, and has 625 scanning lines.
In the video signal standard of book / 50 fields, it is composed of 1728 words.

In the above-mentioned auxiliary signal area 61, FIG.
As shown in (c), ancillary data flag 72, data ID 73, block number 74, data count 7
5, line number 76, line number CRCC 77, code (01h) 78, destination address 7
9, a source address 80, a block type (C1h; variable length) 81, a CRC flag 82, a data start position 83, a reserved area 84, a header CRCC 85, and a checksum 86 are provided.

The ancillary data flag 72 is set to 1
It is a code composed of three words of (000, 3FF, 3FF) h of a hexadecimal signal. The data ID 73 indicates the contents of the auxiliary signal. For example, digital audio data, a time code, an error detection code, and the like. The block number 74 is for detecting the continuity of the data packet, and the data count 75 is for counting the number of words of the user data in the auxiliary signal. The line number 76 indicates any horizontal line (scanning line) number from 1 to 525 (625). The destination address 79 indicates the address of the data transmission destination, and the source address 80 indicates the address of the data transmission source.

Note that each data amount in FIG.
The case of the video signal standard of 25 lines / 60 fields is shown, and the number in parentheses is the number of scanning lines 625 lines / 5.
The data amount in the case of the video signal standard of 0 field is shown.

FIG. 5 shows the bit arrangement of the interface header area. Byte1 and Byte
Reference numeral 2 denotes an area for recording information unique to this interface. Byte3 to Byte10 are reserved areas in which information about the digital VTR standard conforming to such a format is recorded.

The TYPE area 91 shows the contents of the interface header area and the payload area. Specifically, one of the values “0000 0000” and “0000 0001” is used. The former indicates an initial code, and the latter is used when defining the data transfer speed, allocation of five slots in the payload area, and the like.

The reserved area 92 is set to “00” and is not used.

The VIDEO INVALID 93 is information indicating the validity of the video data in the payload area, and 0 is assigned when it is valid and 1 when it is invalid.

The AUDIO INVALID 94 is information indicating the validity of the audio data in the payload area, and 0 is assigned if it is valid and 1 if it is invalid.

The reserved area 95 is not used.

TRANSFER MODE 96 is 00
The validity of the data of the payload and the transfer speed are assigned using 0 to 111.

FIG. 6 shows an example of a format in which the video data and the like shown in FIG. 4 are vertically arranged over the number of lines corresponding to one frame of the analog video signal standard, and are two-dimensionally arranged. The numbers at the right end of FIG. 6 indicate the number of lines in the case of the video signal standard of 525 scanning lines / 60 fields (the number in parentheses is the video signal standard of 625 scanning lines / 50 fields).

In this format, data of five channels from frame 0 to frame 4 can be transferred. Here, the data arrangement is shown only for frame 0. Frames 1 to 4 also have the same data arrangement as frame 0.

The compression-encoded video data includes compressed video data 101, compressed video data 102a and
2b, divided into compressed video data 103 and arranged. This arrangement corresponds to a division method when data is equally divided and recorded on three disk drives.

When transferring data in this format, only arbitrary frames from frame 0 to frame 4 may be used, and all five frames are used to transfer data of five different systems. You may. In addition, in the bit arrangement of the interface header area shown in FIG.
The transfer speed can be specified by the ODE 96. Specifically, by using a plurality of frames to transfer a single signal, the apparent transfer rate is reduced by one.
(Normal) Double speed, double speed, triple speed, quadruple speed, and five times speed can be designated in five stages. For example, 1
When a system signal is transferred using two frames, a double transfer speed can be obtained.

In the data editing apparatus described below, which is configured on the basis of this format, for example, about 1
It is assumed that video data compressed to / 5 is transferred, and the apparent transfer speed can be increased up to a maximum of 5 times. Normally, it is connected to a data editing device, and controls the internal transfer rate in accordance with the data transfer rate of a digital VTR (not shown) used for recording / reproducing material data. For example, when using a digital VTR that can transfer data at 4 × speed, using four frames from frame 0 to frame 3,
Video data can be transferred on the data bus 30 at substantially four times speed. According to such a digital data transmission method, it is possible to synchronize video data and audio data while obtaining a transfer speed of 4 times speed, and further, it is possible to synchronize the entire data with another video data. Editing points can be easily matched.

Next, based on the format described above, in which only the basic video data of 4: 1: 1 is compressed and transmitted, the compressed video data (base data) of 4: 1: 1 is converted into
A description will be given of a format of video data according to the present invention, which is configured to add enhancement data obtained by compressing and encoding a difference from 4: 2: 2 extended video data and transmit the data.

FIG. 7 shows a format for adding enhancement data to base data and transmitting the data, and has a length equal to a period of one horizontal line (scanning line) defined by a predetermined analog video signal standard. The figure shows a state in which base data and enhancement data for four channels are arranged in each time slot obtained by dividing the transmission unit having a plurality of transmission units. Note that the format shown in FIG. 4 transfers only base data obtained by compressing and encoding 4: 1: 1 basic video data, and a maximum of 5 frames of compressed video data is formed during one horizontal line. Although the configuration is for transmission, the difference here is that the configuration is such that four frames are transmitted.

In FIG. 7, portions corresponding to the respective regions in FIG. 4 are denoted by the same reference numerals.

FIG. 7A shows the structure of the entire video data. That is, an EAV (end of active video) area 60 is provided prior to an area where video data is arranged. Subsequent to the EAV area 60, an auxiliary signal area 51, a data area 55d, and a reserve area 52 are provided. The auxiliary signal area 51 and the data area 55
FIG. 7C shows the contents of d. Subsequent to the reserve area 52, an SAV (start of active video) area 62 is provided.

The EAV area 60 and the SAV 62 area are
Each of the hexadecimal signals (3FF, 000,000,000,000, X
YZ) h. The EAV area 60 and the auxiliary signal area 52 have 307 words (Words) in the video signal standard of 525 scanning lines / 60 fields, and 323 words in the video signal standard of 625 scanning lines / 50 fields.

After the SAV area 62, as shown in FIG. 7B, an area including video data is provided. In this data area, the aforementioned base data and enhancement data are arranged.

At the leading end of the area including the video data,
A 6-word data header area including a separator (start code) 66, a type 67, and a word 68 is provided. This data header area is provided only on the twelfth line.

Following the data header area, there is provided an interface header area 71 consisting of 10 words indicating the interface of this transmission system. Following the interface header area 71, a data area in which the base data and the enhancement data are arranged is provided. This data area is composed of four frames of data areas 54a-54 each consisting of 280 clocks (Clocks).
54d and three data areas 55a to 55c each including 280 clocks. The above-mentioned data area 55d is a data area following the above-mentioned 55c.

Each of the data areas 54a to 54d has 256 data areas.
It consists of a valid data area of Bytes and a reserved area of 24 bytes. These effective data areas contain base data of up to four frames.
Each of the data areas 55a to 55d subsequent to the data areas 54a to 54d also has a valid data area of 256 bytes, and stores enhancement data of up to four frames.

The enhancement data of frame 0 (frame 0E) entering data area 55a is stored in data area 5a.
Base data of frame 0 entering 4a (frame 0B)
Is the video data added to. Similarly, the data area 55
Each enhancement data from 55b to 55d is video data added to each base data from data areas 54b to 54d.

Immediately after the data areas 55a and 55b, reserve areas 56 and 57 of 6 bytes are provided, and immediately after the data area 55c, a reserve area 58 of 4 bytes is provided. At the rear end of the reserved area 58, a CRC area 59 described later is provided.

According to this video data format, 4:
When transferring 1: 1 basic video data, only base data is transferred using the data areas 54a to 54d.
At this time, the data areas 55a to 55d are left blank. When transferring 4: 2: 2 extended video data,
Data areas 54a-54d and data areas 55a-5
5d is used together with the base data plus the enhancement data for transfer.

Next to the data area 55c provided at the end of one scanning line period, a 2-word CRC area 59 is provided. This CRC area 59 includes a CRC (not shown).
C (cyclic redundancy check code) 0,
It consists of a CRCC1 area.

Data area 54a within the period forming one scanning line
Reserved area 58 excluding -55c and CRC area 59
In the video signal standard of 525 scanning lines / 60 fields and the video signal standard of 625 scanning lines / 50 fields, both areas are composed of 1920 clocks. Therefore, the period of one scanning line from the EAV area 50 to the CRC area 59 is 2288 clocks in the video signal standard of 525 scanning lines / 60 fields, and the video signal standard of 625 scanning lines / 50 fields. Then, it consists of 2304 clocks.

The above-mentioned auxiliary signal areas 51 and 52
As shown in FIG. 7C, ancillary data flag 72, data ID 73, block number 74, data count 75, line number 76, line number CRC
C77, code (01h) 78, destination address 79, source address 80, block type (C
1h; variable length) 81, CRC flag 82, data start position 83, reserved area 84, header CRCC
85 and a checksum 86 are provided.

After the checksum 86, 307 (32
3) A word data area 87 is provided. The data area 87 includes the data area 55d and the reserve area 52.
Enters.

The ancillary data flag 72 is set to 1
It is a code composed of three words of (000, 3FF, 3FF) h of a hexadecimal signal. The data ID 73 indicates the contents of the auxiliary signal. For example, digital audio data, a time code, an error detection code, and the like. The block number 74 is for detecting the continuity of the data packet, and the data count 75 is for counting the number of words of the user data in the auxiliary signal. The line number 76 indicates one of the scanning line numbers from 1 to 525 (625). The destination address 79 indicates the address of the data transmission destination, and the source address 80 indicates the address of the data transmission source.

Note that each data amount in FIG.
The case of the video signal standard of 25 lines / 60 fields is shown, and the number in parentheses indicates the number of scanning lines 625 lines / 50.
It shows the data amount in the case of the field video signal standard.

Next, a data recording / reproducing apparatus to which the digital data transmission method of the present invention described above is applied will be described.

FIG. 8 is a block diagram schematically showing the configuration of a digital VTR as an embodiment of the data recording / reproducing apparatus. The digital VTR includes an input terminal 201 to which video data is input, a compression encoding unit 202 that compresses and encodes the input video data, records the compression-coded video data on a magnetic tape, and compresses the compressed video data from the magnetic tape. Recording / reproducing system 203 for reproducing video data, magnetic tape 2
10, a recording / reproducing head 204 for writing video data to and reading video data from the magnetic tape 210;
A decompression decoding unit 205 for decompressing and decoding the compression-encoded video data read from the magnetic tape 210 and an output terminal 206 for outputting the decompression-decoded video data are provided.

The compression coding section 202 of this digital VTR
1 uses the compression encoding circuit whose configuration is shown in FIG. 1, and the decompression decoding unit 205 uses the decompression decoding circuit whose configuration is shown in FIG.

The format of the video data recorded on the magnetic tape 210 is, as shown in FIG.
It corresponds to 2: 2 extended video data, and more specifically, has a configuration as shown in FIG. When base data obtained by compressing and encoding 4: 1: 1 basic video data is recorded on the magnetic tape 210, a portion where enhancement data is recorded is left blank.

Therefore, this digital VTR has a 4: 2:
2 and 4: 1: 1 basic video data can be recorded on the magnetic tape 210, and 4: 2: 2 extended video data can be recorded from the video data recorded on the magnetic tape 210. It is also possible to select and reproduce 4: 1: 1 basic video data with video data.

FIG. 9 is a block diagram showing a configuration of a main part of a data editing apparatus to which the above-described digital data transmission method of the present invention is applied.

The data editing apparatus includes a switcher / digital multi-effector 13, an audio mixer 17, four disk drives 18a to 18d, and an input terminal 3 connected to a data bus 30 via a buffer.
2, an output terminal 33 is provided. A digital VTR (not shown) is connected to the input terminal 32 and the output terminal 33 to form a data editing device. This digital V
As shown in FIG. 8, the TR includes a compression encoding circuit for compressing and encoding video data, and a decompression decoding circuit for decompressing and decoding video data that has been compression-encoded, according to the format shown in FIG. It is capable of inputting / outputting 4: 1: 1 compressed video data (base data) and 4: 2: 2 compressed video data obtained by adding enhancement data to base data.

The data editing apparatus further comprises a main CPU 20 and a sub CPU
21, a data transfer controller 22 for controlling data transmission timing and the like, and these are connected to each other by a control bus 31.

Hereinafter, each section of the data editing apparatus will be described.

The buffers 1 to 11 temporarily store data transferred on the data bus 30 and input / output them at a predetermined timing under the control of the data controller 22. This buffer will be described later.

Video data decompression units 12a and 12b
Are connected to data bus 3 via buffers 2 and 3, respectively.
This is for extracting desired compressed video (video) data from 0, decompressing them, and supplying them to the switcher / digital multi-effector 13. Since the switcher / digital multi-effector 13 switches or connects at least two pieces of video data, it is usual that at least two or more video data decompression units 12 are provided.

Switcher / digital multi-effector 1
Reference numeral 3 is for switching a plurality of video data or adding various video effects, and is a part operated by an editor when performing an editing operation.

The video data compression section 14 is provided with a switcher /
The digital multi-effector 13 compresses video data on which desired video processing has been performed, and sends the compressed data to the data bus 30 via the buffer 1.

The audio (sound) data output processing sections 15a and 15b take out desired audio data from the data bus 30 via the buffers 5 and 6, respectively, and supply them to the audio mixer 16. In the audio mixer 16, at least two audio data are mixed or switched, so that at least two or more audio data output processing units 15 are usually provided.

The audio mixer 16 is a part operated by an editor in order to mix a plurality of audio data and to add various sound effects.

The audio data input processing unit 17
The audio data subjected to the audio processing by the audio mixer 16 is transmitted to the data bus 30 via the buffer 4.

The disk drives 18a to 18d temporarily record video data and audio data on a hard disk. Generally, a magnetic disk drive is used. This data editing device converts video data into 4
It can be divided into two or three of the two disk drives 18a to 18d and recorded.

The SPCs 19a to 19d are device controllers for controlling the input and output of video data and audio data to be recorded / reproduced on / from the disk drives 18a to 18d.
C) and the like.

The above disk drives 18a to 18d
Are SPCs 19a to 19d and buffers 7 to 10, respectively.
Is connected to the data bus 30 via Also, SPC
19a to 19d and buffers 7 to 10 are connected to a control bus 31.

The main CPU 20 and the sub CPU 21 are for controlling the operation of each section of the data editing device, and are both connected to the control bus 31.

The data transfer controller 22 is connected between the data bus 30 and the control bus 31, generates a transfer control command based on data transfer control information from the main CPU 20 and the sub CPU 21, and supplies it to the data bus 30. The data transferred on the data bus 30 is input / output at a predetermined timing from each buffer by the transfer control command.

The interface units 23 and 24 are both provided on the control bus 31 and serve as interfaces for control data transmitted and received between the units.

The serial / parallel converter 26 converts serial data input from the input terminal 32 into parallel data.

The gate 27 transfers the data from the serial / parallel converter 26 to the data bus 30 at a predetermined timing.
To be sent to

The gate 28 converts the desired data extracted from the data bus 30 into a parallel / serial converter 28.
It is for supplying to.

The parallel / serial converter 29 converts data from the gate 28 into serial data and outputs the serial data from the output terminal 33.

[0124]

According to the digital data transmission method of the present invention,
Base video data obtained by compression-encoding 4: 1: 1: basic video data is added with enhancement data mainly including high-frequency components to substantially form 4: 2: 2 compressed video data. According to this digital data transmission method,
When transferring 4: 1: 1 basic video data, only the base data needs to be transferred, and when transferring 4: 2: 2 extended video data that can obtain high-definition video, What is necessary is just to transfer the base data with the enhancement data added thereto. Therefore, compatibility between these video data having different compression formats can be obtained.

Further, since the data recording / reproducing apparatus to which the digital data transmission method of the present invention is applied is provided with means for compression-encoding and decompression-decoding the base data and the enhancement data, respectively, the data recording / reproducing apparatus has a 4: 1:
1 and 4: 2: 2 video data can be recorded / reproduced.

Further, the data editing apparatus of the present invention includes a data recording / reproducing apparatus provided with means for compressing and encoding base data and enhancement data and decompressing and decoding the data. 4: 1: 1 basic video data and 4:
Any of the 2: 2 extended video data can be transferred as compressed video data. Therefore, 4: 1: 1
When editing video data of 4: 2: 2 and video data of 4: 2: 2, both data can be edited as they are as compressed video data, and deterioration of image quality of edited video due to repeated expansion / compression can be prevented. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a compression encoding circuit to which a digital data transmission method according to the present invention is applied.

FIG. 2 is a block diagram showing a basic configuration of a decompression decoding circuit corresponding to the data compression encoding circuit.

FIG. 3 is a diagram for explaining an interface and a data structure in the digital data transmission method of the present invention.

FIG. 4 is a diagram illustrating a structure of a transmission unit in which 4: 1: 1 digital video data is transmitted.

FIG. 5 is a diagram showing a structure of a header section of the digital video data.

FIG. 6 is a diagram showing an example of a format of data transferred between the data editing device and an external device.

FIG. 7 is a diagram showing a configuration of video data in the digital data transmission method of the present invention.

FIG. 8 is a block diagram schematically showing a data recording / reproducing apparatus to which the digital data transmission method of the present invention is applied.

FIG. 9 is a block diagram illustrating a configuration example of a data editing device to which the digital data transmission method according to the present invention is applied.

[Explanation of symbols]

110, 120 input terminals, 111, 121 blocking unit, 112 DCT (discrete cosine transform) unit,
113 quantization unit, 114 two-dimensional Huffman coding unit, 115, 125 framing unit, 116, 1
26 output terminal, 117 low-pass filter (LP
F), 118 inverse quantization section, 119 inverse DCT (inverse discrete cosine transform) section, 122 selector, 123
Subtraction circuit, 124 enhancement data encoding unit

Claims (8)

[Claims] 1. A basic video data in which the ratio of the sampling frequency of a luminance signal to the sampling frequency of two color difference signals is 4: 1: 1, or the ratio of the sampling frequency of a luminance signal to the sampling frequency of two color difference signals is 4:
A digital data transmission method for transmitting extended video data of 2: 2, wherein the transmission data of the extended video data includes base data obtained by compression-encoding the basic video data, the extended video data and the basic video data. A digital data transmission method characterized by adding enhancement data obtained by compression encoding by taking a difference from the data. 2. A transmission unit having a length equal to a period forming one horizontal line of a video image specified by a predetermined analog video signal standard is divided into a plurality of transmission units. And transmitting at least one frame of each of the basic video data and the enhancement data of the plurality of channels by the transmission unit having the number of lines corresponding to one frame of the video defined by the analog video signal standard. 2. The digital data transmission method according to claim 1, wherein: 3. The digital data transmission method according to claim 2, wherein the transmission data of the extended video data is transmitted by arranging enhancement data corresponding to a half of the plurality of slots. . 4. The digital data transmission method according to claim 2, wherein said digital video data of a plurality of channels is divided in a two-dimensional array in a vertical direction and recorded in a plurality of recording means. 5. The multi-channel digital video data is transmitted in synchronization with a horizontal synchronization signal and a vertical synchronization signal of a reference video signal.
Digital data transmission method as described. 6. The digital data transmission method according to claim 1, wherein the basic video data is transmitted at 270 Mbps, and the extended video data is transmitted at 360 Mbps. 7. The video data is compression-encoded and the ratio of the sampling frequency of the luminance signal to the sampling frequency of the two color difference signals is 4: 1:
A first compression-encoding means for generating basic video data of 1; extended video data having a sampling frequency of a luminance signal and a sampling frequency of two color difference signals of 4: 2: 2; A second compression encoding means for generating enhancement data by taking a difference between the first and second compression encoding means, and recording the compression-encoded video data on a recording medium;
Recording / reproducing means for reproducing video data from the recording medium; first decompressing / decoding means for decompressing and decoding the reproduced video data to obtain the basic video data; and second means for generating the extended video data. Data recording / reproducing apparatus, comprising: 8. The video data is compression-coded, and the ratio of the sampling frequency of the luminance signal to the sampling frequency of the two color difference signals is 4: 1:
First encoding means for generating basic video data of 1; extended video data having a ratio of a sampling frequency of a luminance signal to a sampling frequency of two color difference signals of 4: 2: 2; Second encoding means for generating enhancement data by taking the difference between the first and second video data, first decoding means for decompressing and decoding the basic video data, and second decoding for decompressing and decoding the enhancement data. Means; recording and reproducing means for recording the basic video data and enhancement data on a recording medium and reproducing the basic video data and enhancement data from the recording medium; and a bus for transferring the basic video data and enhancement data. A data editing device characterized by the following.