JP2002051027A - Data transmission method and data transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data transmission system where composite 8-bit word sequence data are formed by adding word synchronizing data to a compressed digital video signal and transmitted as serial data in a way that a receiver side can surely receive the serial data. SOLUTION: The compressed digital video signal is obtained by applying data compression to a digital video signal by each frame period and forms the 8-bit word sequence data where a part with compressed data existing therein and a part with no compressed data existing therein are alternately consecutive to each other. An attached word data group including 8-bit word synchronous data with predetermined code assignment is inserted to parts of the compressed digital video signal where no compressed data exist to form the composite 8-bit word sequence data, the composite 8-bit word sequence data are converted into the serial data and the serial data are transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The invention described in the claims of the present application relates to a compressed digital signal forming 8-bit word string data obtained by subjecting a digital video signal to data compression in units of a predetermined section period. The present invention relates to a data transmission method for inserting an additional word data group including word synchronization data into a video signal and transmitting the resulting composite 8-bit word string data to be transmitted, and a data transmission apparatus provided for implementing the method.

[0002]

2. Description of the Related Art In the field of transmission of digital data including information data representing various kinds of signal information such as image information, an electric signal based on digital data is obtained, and is used by a coaxial cable or twisted pair line or the like. A system for transmitting digital data through a transmission line formed by using an optical fiber, and a system for transmitting digital data to an optical signal and transmitting the same through a transmission line formed using an optical fiber have been put into practical use. The transmission format of digital data is an STM (Synchronous Transfer Mode) format in which a fixed frame period is set, and an ATM (Asynchronous Transport Mode) in which a fixed frame period is not set.
nsfer Mode) format.

[0003] The current digital network formed by adopting such a digital data transmission system has been developed based on a telephone line network. With the development of digital network transmission, multiplexing of data and high-speed broadening of signals based on data to be transmitted are inevitably pursued in order to realize efficient data transmission. As one of the techniques for multiplexing digital data and transmitting it as a high-speed wideband signal, SDH (Synchronous
A technology called Digital Hierarchy) has been established in ITU-T (formerly CCIR).

[0004] The SDH proposes a new STM format that is compatible with future high-speed broadband services.
A synchronous multiplexing structure having a basic unit called TM-1 is adopted. As shown in FIG. 7, STM-1 has nine rows, that is, 270 bytes (Byte; 1 byte = 8 bits (Bit)) of data divisions.
This is a transmission signal having a period of 270 bytes × 9 = 2,430 bytes, and such a unit period division is called a “frame”. 270 in each of the nine rows forming each frame
The first 9 of the bytes form the section overhead (SOH) and AU pointer, and 2
The remaining 261 bytes of the 70 bytes form an information area.

[0005] The SOH and AU pointers consist of a total of 9 bytes x 9 = 81 bytes, which include A1, A2, B
1, B2, C1, D1 to D12, E1, E2, F1, K
1, K2, H1, H2, H3, Z1, and Z2 are included. These have the contents as shown in FIG. 7, respectively, wherein A1 and A2 (frame pattern) are 8-bit word synchronization data, and A1 and A2 of three consecutive bytes at the beginning of the first row. The succeeding 3-byte A2 forms a synchronization pattern in each frame. Each of the 8-bit word synchronization data A1 and A2 has been assigned a predetermined code, and A1
Is assigned “11110110”, and A2
Is assigned “00101000”.

[0006] One cycle of the STM-1 is set to 125 µsec. Therefore, the transmission capacity is 270 bytes x 9 x 1/1.
25 × 10 ⁻⁶ seconds × 8 = 155.520 megabits / second (155.520 Mbps).

Further, transmission using STM-1 has been further developed, and high-speed transmission in which a plurality of STM-1s are multiplexed has been proposed, and a transmission signal at that time is referred to as STM-N. The STM-N is, for example, as shown in FIG.
-1, # 2,..., STM-1 #n are formed by byte interleaving multiplexing in the data multiplexing unit 10.

As a communication service employing SDH as described above, SONET (Synchronous Optimal
A high-speed data transmission service called “cal Network” is known.

On the other hand, in the field of video signals, digitization has been attempted from the viewpoint of realizing diversification of transmitted information and high quality of reproduced images. For example, digital data (image data) representing video signal information has been developed. High-definition television (HDTV) systems that handle digital video signals formed by information data) have been proposed. The digital video signal (HD digital video signal) under the HDTV system follows, for example, a data format as shown in FIG.

The data format of the digital video signal shown in FIG. 9 is a brightness signal data sequence (Y data sequence) representing a brightness signal component in the video signal as shown in FIG. since it illustrated in as being a color difference signal data sequence representing the color difference signal component in the video signal (P _B / P _R data sequence) to become, Y
The data sequence and the P _B / P _R data sequence represent luminance signal information data forming a digital video signal and color difference signal information data forming a digital video signal, respectively.

Each of the word data forming each of the Y data sequence and the P _B / P _R data sequence has a 10-bit configuration. That is, each of the color difference signal information data represented as luminance signal information data and the P _B / P _R data sequence represented as Y data sequence, quantization with 10-bit word is image information data has been made. FIG. 9A illustrates a line blanking period in each line period in the Y data series and a portion corresponding to a part of the video data period before and after the line blanking period. It has been shown a portion corresponding to a portion of the video data period in the line blanking period and before and after in each line period in the P _B / P _R data sequence.

In the Y data series, immediately before a portion corresponding to each video data period, four words (3FF (Y), 000 (Y), 000) each having a 10-bit configuration.
(Y), XYZ (Y)), timing reference code data (SAV: Start of Active Video) is provided, and each of them has a 10-bit configuration immediately after a portion corresponding to each video data period. Word (3FF (Y),
000 (Y), 000 (Y), XYZ (Y)), and timing reference code data (EAV: End of Active).
Video) is arranged. Similarly, P _B / P _R data be in sequence, just before the portion corresponding to the respective video data period, four words, each of which is a 10-bit configuration (3FF
(C), 000 (C), 000 (C), XYZ (C))
And a 4 word (3FF (C), 000 (C), 000) immediately after a portion corresponding to each video data period, each of which has a 10-bit configuration.
(C), XYZ (C)). Of course, Y data EAV and SAV Each of the in series arranged in a portion corresponding to the line blanking period in the Y data sequence and, EAV in P _B / P _R data sequence
And each of the SAV is arranged at a portion corresponding to each line blanking period in P _B / P _R data sequence.

[0013] In the digital video signal according to the data format consisting of such Y data sequence and P _B / P _R data sequence is transmitted, Y data sequence and P _B /
The P _R data sequence, the word multiplexing process at Moto the portion corresponding to the line blanking period, each of EAV are disposed has been made to the synchronization is performed, the word multiple data series as shown in FIG. 10 formed Is done.

[0014] Such HD digital video signals include:
Interlaced scanning in which each frame image is formed by being divided into a first field image and a second field image, and sequential scanning in which each frame image is formed without being divided into a first field image and a second field image There is a business. The HD digital video signal for interlaced scanning is 10-bit word string data with a transmission rate of, for example, 148.5 MBps, and the HD digital video signal for progressive scanning has a transmission rate of H for interlaced scanning.
D digital video signal, for example, 148.
It is 10-bit word string data with 5 MBps × 2 = 297 MBps.

[0015] Further, the amount of image information data which forms an HD digital video signal for interlaced scanning or an HD digital video signal for progressive scanning usually has an enormous amount of data. In performing such operations, it is desired that data compression be performed so that the data amount can be reduced without substantially lowering the data quality. Therefore, various researches and developments have been made on data compression techniques for reducing the data amount of image information data. One of the results is, in particular, image information data representing moving image information. As a method of implementing data compression, MPEG (Moving), a working group under the technical committee under the International Standards Organization,
A standard scheme called MPEG has been proposed, which has been examined and approved as a standard by the Picture Experts Group.

In the standard method called MPEG, image information data is subjected to data compression by high-efficiency coding.
When data compression by high-efficiency encoding according to EG is performed, data compression with an extremely high compression rate can be realized.
In addition, there is obtained an advantage that an image reproduced based on digital image information data subjected to data compression can be of high quality. Digital image information data (MPEG image information data) that has been subjected to data compression by high-efficiency encoding according to MPEG generally forms 8-bit word string data.

When data compression processing using MPEG is performed on the above-described interlaced scanning HD digital video signal or progressive scanning HD digital video signal, for example, interlaced scanning HD digital video signal or sequential For HD digital video signals for scanning,
Data compression is performed in units of one frame period, which is the section period in that case. That is, data compression by high-efficiency coding according to MPEG is performed on image information data representing each frame period in the HD digital video signal for interlaced scanning or the HD digital video signal for progressive scanning. Compressed data as 8-bit word string data is sequentially formed.

As a result, based on the HD digital video signal for interlaced scanning, a compressed digital video signal (compressed digital video signal) in which a portion where compressed data is present and a portion where no compressed data is present are alternately connected to form 8-bit word string data. DCI) or a compressed digital video signal (compressed digital video signal DCP) based on an HD digital video signal for progressive scanning, in which a portion where compressed data exists and a portion where no compressed data exists alternately continue to form 8-bit word string data. ) Is formed. In such a compressed digital video signal DCI or DCP, one frame period corresponds to a portion where compressed data formed by data compression by high-efficiency coding according to MPEG exists and a portion where no subsequent compressed data exists. And will be formed by

FIG. 11 shows a compressed digital video signal DCI
Alternatively, an example of DCP is shown. FIG. 11A shows a sequence of each frame period (one frame) in the compressed digital video signal DCI or DCP. In each frame period, a portion where compressed data exists and a portion where compressed data does not exist (blank). Are connected.

FIG. 11B shows a sequence layer for forming compressed data. The sequence layer indicates that the sequence header code (SHC: 000001B3 (H), (H) is expressed in hexadecimal), and the same applies to the following. .), Followed by a plurality of group of pictures (GOP), and ends with a sequence end code (SEC: 000001B7 (H)). FIG.
C indicates a GOP constituting the sequence layer, and GOP
Is the group start code (GSC: 00000
1B8 (H)), and a plurality of pieces of picture data are formed continuously. D in FIG. 11 shows picture data constituting a GOP, and the picture data is a picture start code (PSC: 00000100).
(H)), and a plurality of slice data are connected to it.

Further, FIG. 11E shows slice data constituting picture data. The slice data starts with slice information, and a plurality of macroblock data are connected to the slice information. F of FIG. 11 shows macroblock data constituting slice data. The macroblock data starts with macroblock information, and is configured by a plurality of block data connected thereto. G in FIG.
Indicates block data constituting macroblock data, and the block data is a discrete cosine transform (DCT).
Is obtained as DCT data. Note that, in FIG. 11, an arrow t indicates a lapse of time.

[0022]

The transmission side also transmits a compressed digital video signal, such as the above-mentioned compressed digital video signal DCI or DCP, formed by performing a data compression process using MPEG. Based on the compressed digital video signal to be processed, for example, like the aforementioned 8-bit word synchronization data A1 and A2,
An 8-bit word string data to which word synchronization data to which a predetermined code is assigned is added, and the 8-bit word string data is transmitted to be transmitted as serial data. What is done to ensure that it is played is
For example, in configuring a transmission / reception circuit, for example, an existing integrated circuit element (I
This is desired from the viewpoint that C element and the like can be used effectively. Also, when the compressed digital video signal to be transmitted at this time is one of two types having different transmission rates, a state in which it is properly transmitted is automatically taken. This is even more desirable.

However, conventionally, on the transmission side, a compressed digital video signal formed by performing data compression processing using MPEG is converted into, for example, the aforementioned 8-bit word synchronous data A1 and A2 based on the compressed digital video signal. And an 8-bit word string data to which word synchronization data to which a predetermined code is assigned is added, and the 8-bit word string data is transmitted to be transmitted as serial data. However, there is no concrete example that realizes a transmission system capable of transmitting data so as to be surely reproduced on the receiving side. In addition, such M
The receiving side compresses 8-bit word string data obtained by adding word synchronization data to which a predetermined code is assigned to a compressed digital video signal formed by performing data compression processing using PEG. There is also no literature describing a technique relating to a transmission system capable of transmitting a digital video signal while reliably reproducing the digital video signal.

[0024] In view of the above, the invention described in the claims of the present application provides, for example, a compressed digital video signal formed by performing data compression processing using MPEG based on a predetermined digital video signal. 8-bit word string data to which the word synchronization data to which the code has been assigned is added is formed, and the 8-bit word string data is reliably reproduced on the receiving side by a transmission method in which the 8-bit word string data is transmitted to be transmitted as serial data. Can be transmitted as much as possible,
Further, even when the compressed digital video signal is one of two types having different transmission rates, the data transmission method and the implementation of the data transmission method that can transmit the data properly are provided. Provided data transmission device.

[0025]

According to a first aspect of the present invention, there is provided a data transmission method in which a digital video signal is divided into units of a predetermined section period. A portion of the compressed digital video signal obtained by performing the data compression described above, in which the portion where the compressed data exists and the portion where the compressed data does not exist are alternately connected to form 8-bit word string data, By inserting an additional word data group including 8-bit word synchronization data to which a predetermined code is assigned, composite 8-bit word sequence data is formed, and the obtained composite 8-bit word sequence data is converted into serial data. The serial data is converted and transmitted for transmission.

In particular, in the data transmission method according to the present invention described in each of claims 4 and 5 in the claims of the present application, the compressed data constituting the compressed digital video signal is converted into a predetermined format of the digital video signal. 8-bit word string data obtained by performing data compression by high-efficiency coding on image information data corresponding to a section period, for example, each frame period.

A data transmission apparatus according to a seventh aspect of the present invention is characterized in that a data compression is obtained by performing data compression on a digital video signal in units of a predetermined section period. An 8-bit word in which a predetermined code is assigned to a portion of a compressed digital video signal in which compressed data does not exist in a compressed digital video signal in which a portion in which data exists and a portion in which no data exists alternately form 8-bit word string data. A compound word string data forming means for forming compound 8-bit word string data by inserting an additional word data group including synchronization data, and a compound 8-bit word string data obtained from the compound word string data forming means are converted into serial data. And data transmission means for transmitting the serial data for transmission.

According to the data transmission method according to any one of the first to sixth aspects of the present invention as described above, the digital video signal to be transmitted is transmitted. A predetermined code is assigned to composite 8-bit word string data based on a compressed digital video signal that forms 8-bit word string data obtained by performing data compression in units of a predetermined section period. 8 bit word synchronization data. Such 8-bit word synchronization data is, for example, 8-bit word synchronization data A1 and A2 used in SDH. Further, for example, three 8-bit word synchronization data A1 are continuously connected. Subsequently, three 8-bit word synchronization data A2 are continuously connected.

The composite 8-bit word string data including the 8-bit word synchronization data to which a predetermined code is assigned and transmitted as serial data is converted into an 8-bit word at the receiving side. Synchronous data is properly detected as word synchronous data required for processing for converting serial data to parallel data and for reproducing compressed digital video signals from composite 8-bit word string data. It will be. Therefore, on the receiving side, a state in which the data synchronization state required for the reproduction processing of the compressed digital video signal based on the received composite 8-bit word string data is reliably obtained.

That is, according to the data transmission method according to any one of the first to sixth aspects of the present invention, the digital video signal is formed by performing data compression processing. The compressed digital video signal is formed into complex 8-bit word string data to which word synchronization data to which a predetermined code is assigned is added based on the compressed digital video signal, and the combined 8-bit word string data is transmitted as serial data. With the transmission method transmitted as much as possible, it is possible to transmit the data so that the data can be reliably reproduced on the receiving side.

Further, when the composite 8-bit word string data based on the compressed digital video signal is transmitted as serial data, for example, it is used for SDH.
Existing IC elements and the like can be effectively used.

[0032] In particular, according to the data transmission method according to the invention described in each of claims 4 and 5 in the claims of the present application, for a predetermined section period of the digital video signal, for example, each frame period For example, a compressed digital video signal forming 8-bit word string data obtained by performing data compression by high-efficiency encoding in accordance with MPEG on image information data representing The composite 8-bit word sequence data to which the word synchronization data assigned is assigned, is formed, and the composite 8-bit word sequence data is transmitted to be transmitted as serial data, and is reliably reproduced on the receiving side. It is transmitted as much as possible.

Further, according to the data transmission device according to the invention described in claim 7 of the present application,
The compressed digital video signal formed by performing data compression processing on the digital video signal by the composite word string data forming means and the data sending means is added with word synchronization data to which a predetermined code is assigned based on the compressed digital video signal. Thus, the received 8-bit word string data is formed, and the 8-bit word string data can be transmitted so as to be surely reproduced on the receiving side by the transmission method of transmitting the serial data.

The data transmitting means for transmitting the composite 8-bit word string data based on the compressed digital video signal as serial data is constituted by effectively utilizing an existing IC element or the like for SDH. Can be done.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a data transmission method according to the present invention described in any one of the first to sixth aspects of the present invention. An example of the data transmission device according to the invention described in claim 7 in the range of FIG.

In the example shown in FIG. 1, the compressed digital video signal DCI or the compressed digital video signal D
The CP is supplied to the composite word string data forming unit 11 as a compressed digital video signal to be transmitted.

The compressed digital video signal DCI is obtained, for example, by subjecting the HD digital video signal for interlaced scanning to data compression in units of a predetermined divisional period, so that, for example, the segmented period in the HD digital video signal for interlaced scanning is obtained. Is obtained by performing data compression by high-efficiency coding in accordance with MPEG on image information data representing one frame period, which is equivalent to one frame period.
Based on the D digital video signal, a portion having compressed data and a portion not present (blank) are alternately connected to form 8-bit word string data. For example, a compression having a data structure as shown in FIG. It is a digital video signal. In the compressed digital video signal DCI, each set of a portion where compressed data exists and a portion where no compressed data exists forms one frame period. The compressed digital video signal DCI is 8-bit word string data having a word transmission rate of, for example, 74.25 MBps.
The clock frequency of the CI is, for example, 74.25 MHz.

The compressed digital video signal DCP is obtained by subjecting the HD digital video signal for progressive scanning to data compression in units of a predetermined section period, for example, for each frame in the HD digital video signal for progressive scanning. The image information data representing the period is obtained by performing data compression by high-efficiency coding according to MPEG, and is based on an HD digital video signal for progressive scanning.
A portion where the compressed data exists and a portion where the compressed data does not exist are alternately connected to form 8-bit word string data. For example,
It is a compressed digital video signal having a data structure as shown in FIG. This compressed digital video signal DC
In P, each set of a portion where compressed data exists and a portion where no compressed data exists forms one frame period. The compressed digital video signal DCP is 8-bit word string data having a word transmission rate of, for example, 148.5 MBps. Therefore, the clock frequency of the compressed digital video signal DCP is, for example, 148.5.
MHz.

The compound word string data forming section 11 has a compressed digital video signal DCI or D
A word in which the frequency of the horizontal synchronizing signal SH and the vertical synchronizing signal SV synchronized with the line period, the field period or the frame period of the CP, and the frequency of the compressed digital video signal DCI or DCP supplied thereto is 74.25 MHz or 148.5 MHz. A clock signal CX is supplied, and a clock signal CA having a frequency of 77.76 MHz is also supplied.

In the composite word string data forming section 11, the compressed digital video signal DCI or DCP is
The data is supplied to the speed conversion / synchronization data insertion unit 12. The speed conversion / synchronous data insertion unit 12 has a word clock signal C
X, the horizontal synchronization signal SH, the vertical synchronization signal SV, and the clock signal CA are also supplied.

The compound word string data forming section 11 includes a word data transmitting section 13 for transmitting the additional word data group DWS. The additional word data group D sent from the word data sending unit 13
The WS has a word transmission rate of 77.76 MBps, includes 8-bit word synchronization data, and is supplied to the speed conversion / synchronization data insertion unit 12.

The speed conversion / synchronous data insertion unit 12
, The word transmission rate of the compressed digital video signal DCI or DCP forming 8-bit word string data is set to 74.25 MBps or 14
A speed conversion process for changing from 8.5 MBps to 77.76 MBps is performed. Further, in the speed conversion / synchronization data insertion unit 12, a portion of the compressed digital video signal DCI or DCP subjected to the speed conversion process, in which no compressed data exists after the portion in which the compressed data exists in each frame period, exists. (Blank), the word transmission rate from the word data transmission unit 13 is 77.76 MBp
An additional word data group DWS including 8-bit word synchronization data as s is inserted to form composite 8-bit word string data DZ (8) having a word transmission rate of 77.76 MBps as shown in FIG. I do. In addition,
The arrow t in FIG. 2 indicates the passage of time (similar in other figures).

FIG. 3 shows a speed conversion / synchronous data insertion unit 12.
The following is a specific configuration example of. In the example shown in FIG. 3, the compressed digital video signal DCI or DCP supplied to the composite word string data forming unit 11 is supplied to the switch 18. The switch 18 is also supplied with a control signal CSA from a switch control signal forming unit 19.

The switch control signal forming section 19 is supplied with the horizontal synchronizing signal SH and the vertical synchronizing signal SV. The switch control signal forming section 19 generates the control signal CSA according to the horizontal synchronizing signal SH and the vertical synchronizing signal SV. , The compressed digital video signal D supplied to the complex word string data forming unit 11
It is formed as synchronized with each frame period in CI or DCP.

The switch 18 is connected to a memory section 20 and a memory section 21. The switch 18 performs switching at the beginning of each frame period in the compressed digital video signal DCI or DCP in accordance with the control signal CSA synchronized with each frame period in the compressed digital video signal DCI or DCP. Thereby, the compressed digital video signal DCI or DCP
Are stored in the memory unit 20 and the memory unit 21 for one frame period.
And a memory unit 20 and a memory unit 21 for the compressed digital video signal DCI or DCP.
Is set in a state in which the distribution supply is performed for.

In connection with the memory units 20 and 21,
The memory control signal forming unit 22 is provided, and the word clock signal CX and the clock signal CA are supplied to the memory control signal forming unit 22. Then, the memory control signal forming section 22 generates a write control signal QW having a frequency of 74.25 MHz based on the word clock signal CX, and reads out a frequency having a frequency of 77.76 MHz based on the clock signal CA. A state in which the control signal QR is generated (when the compressed digital video signal DCI having a word transmission rate of 74.25 MBps is supplied to the composite word string data forming unit 11) or the frequency is determined based on the word clock signal CX. A write control signal QW of 148.5 MHz is generated, and a clock signal C
A state in which a read control signal QR having a frequency of 77.76 MHz is generated based on A (when a compressed digital video signal DCP having a word transmission rate of 148.5 MBps is supplied to the composite word string data forming section 11) Then, the write control signal QW and the read control signal QR are supplied to both the memory units 20 and 21.

In the memory section 20, when the compressed digital video signal DCI is supplied to the composite word string data forming section 11, the compressed digital video signal DCI is supplied through the switch 18 during the compression digital video signal DCI. One frame period of the video signal DCI is written in a state where the word transmission rate is 74.25 MBps according to the write control signal QW having a frequency of 74.25 MHz. Further, even in the memory unit 21, the compressed digital video signal D
When the CI is supplied, during the period in which the compressed digital video signal DCI is supplied through the switch 18, one frame period of the compressed digital video signal DCI corresponds to the write control signal QW having a frequency of 74.25 MHz. Writing is performed with the word transmission rate set to 74.25 MBps.

Therefore, when the compressed digital video signal DCI is supplied to the composite word string data forming unit 11,
Writing in a state in which the word transmission rate for one frame period of the compressed digital video signal DCI is 74.25 MBps in the memory units 20 and 21 is performed at the beginning of each frame period of the compressed digital video signal DCI. The switching is performed alternately according to the switching of the switch 18.

Further, in the memory section 20, the compressed digital video signal DCP
Is supplied, during a period in which the compressed digital video signal DCP is supplied through the switch 18, one frame period of the compressed digital video signal DCP is converted into a word in accordance with the write control signal QW having a frequency of 148.5 MHz. Writing is performed with the transmission rate set to 148.5 MBps. Further, even when the compressed digital video signal DCP is supplied to the compound word string data forming unit 11 even in the memory unit 21, the compressed digital video signal DCP is supplied during the period in which the compressed digital video signal DCP is supplied through the switch 18. The frequency for one frame period is 1
According to the write control signal QW of 48.5 MHz, writing is performed in a state where the word transmission rate is 148.5 MBps.

Therefore, when the compressed digital video signal DCP is supplied to the composite word string data forming unit 11,
Writing at a word transmission rate of 148.5 MBps for one frame period of the compressed digital video signal DCP in the memory units 20 and 21 is performed at the beginning of each frame period of the compressed digital video signal DCP. The switching is performed alternately according to the switching of the switch 18.

One frame period of the compressed digital video signal DCI or DCP written in the memory unit 20 corresponds to the compressed digital video signal DC following the writing period.
In a period corresponding to one frame period of I or DCP, in accordance with a read control signal QR having a frequency of 77.76 MHz, 8 bits are read from the memory unit 20 in order to sequentially form 8-bit words. It is assumed. At this time, the compressed digital video signal DCP is stored in the memory unit 20.
Is written in the memory unit 20, a part of the end portion of the portion of the compressed digital video signal DCP in which one frame period of the compressed digital video signal DCP is not present is not read out. Is a portion where the compressed data does not exist, so that no particular trouble occurs.

As a result, 8-bit word string data DX ′ (8) having a word transmission rate of 77.76 MBps is obtained from the memory unit 20 and supplied to the switch 23.

Similarly, one frame period of the compressed digital video signal DCI or DCP written in the memory unit 21 is a period corresponding to one frame period of the compressed digital video signal DCI or DCP following the writing period. In the meantime, in accordance with a read control signal QR having a frequency of 77.76 MHz, 8 bits are read from the memory unit 21 to form 8 bit words sequentially. At this time, when the compressed digital video signal DCP is written to the memory unit 21, one end of the portion of the compressed digital video signal DCP written to the memory unit 21 where no compressed data exists for one frame period is present. Although no part is read out, such a part that is not read out is a part in which no compressed data is present, so that no particular problem occurs.

As a result, 8-bit word string data DX ′ (8) having a word transmission rate of 77.76 MBps is obtained from the memory unit 21 and supplied to the switch 23.

The switch 23 is also supplied with a control signal CSA from the switch control signal forming section 19 which is synchronized with each frame period of the compressed digital video signal DCI or DCP supplied to the composite word string data forming section 11. . Then, the switch 23 alternately extracts the 8-bit word string data DX ′ (8) read from the memory unit 20 and the 8-bit word string data DX ′ (8) read from the memory unit 21 according to the control signal CSA. , Thereby increasing the word transmission rate to 77.76 MBps
To form 8-bit word string data DX (8).

The 8-bit word string data DX (8) formed by the switch 23 in this manner is applied to the compressed digital video signal DCI or DCP supplied to the composite word string data forming section 11 so that the word transmission rate is 7
7 from 4.25 MBps or 148.5 MBps
This is a compressed digital video signal obtained by performing transmission rate conversion to convert to 7.76 MBps. Then, the 8-bit word string data DX (8) obtained from the switch 23
Is supplied to the switch 24 and the SHC; SE
It is supplied to the C detection unit 25.

SHC: In the SEC detector 25, the compressed digital video signal 8 which has been subjected to transmission rate conversion is 8
As shown in FIG. 11B, SHC and SEC included in the compressed data in each frame period of the bit word string data DX (8) are detected, and an SHC detection output signal SSH corresponding to the detected SHC is detected. And an SEC detection output signal SSE corresponding to the detected SEC.

SHC: The SHC detection output signal SSH and the SEC detection output signal SSE from the SEC detection section 25 are supplied to a control signal formation section 26. Control signal forming unit 26
Is a control signal CSB corresponding to the SHC detection output signal SSH.
And a control signal CSC corresponding to the SEC detection output signal SSE and supply them to the switch 24. The control signal CSB is supplied to the switch 24 in synchronization with the SHC located at the start end of the compressed data in each frame period of the 8-bit word string data DX (8) obtained from the switch 23. Is supplied to the switch 24 in synchronization with the SEC located at the end of the compressed data in each frame period of the 8-bit word string data DX (8) obtained from the switch 23.

The switch 24 has 8
In addition to the bit word string data DX (8), the word transmission rate from the word data transmitting unit 13 is 77.76 MB.
An additional word data group DWS of ps is supplied. The switch 24 is connected to the switch 23 from the start of the supply of the control signal CSB from the control signal forming unit 26 to the end of the supply of the control signal CSC from the control signal forming unit 26 thereafter. When the supply of the control signal CSC from the control signal forming unit 26 is completed and thereafter, the supply of the control signal CSB from the control signal forming unit 26 is started. In the meantime, the operation of extracting the additional word data group DWS from the word data sending unit 13 is repeated. Thereby, by the switch 24,
8-bit word string data DX (8) from switch 23
, The portion where the compressed data exists in each frame period is extracted, and the state where the additional word data group DWS from the word data sending unit 13 is extracted following the portion where the compressed data exists is repeated.

As a result, the switch 24 adds the additional word data group DWS to the 8-bit word string data DX (8) in the portion where the compressed data in each frame period does not exist after the portion in which the compressed data exists. 2, each frame period is composed of compressed data followed by an additional word data group DWS, and the word transmission rate is 77.76 MBps, as shown in FIG. Thus, composite 8-bit word string data DZ (8) is obtained.

At this time, the 8-bit word string data DX (8) obtained from the switch 23 is added to the additional word data group DWS from the word data transmitting unit 13.
Is detected in the compressed data in each frame period of the 8-bit word string data DZ (8), in which the portion in which the compressed data is present in each frame period is detected following the portion in which the compressed data is present in each frame period. SEC and SHC are detected.

The additional word data group DWS having a word transmission rate of 77.76 MBps from the word data transmitting unit 13 includes a plurality of 8-bit word data including 8-bit word synchronization data to which a predetermined code is assigned. For example, at the start end portion, three 8-bit word synchronization data A1 (to which a predetermined code "11110110" is allocated) are consecutive, Of 8
Bit word synchronization data A2 (to which a predetermined code "00101000" is assigned) continues, and three 8-bit word synchronization data A1 also continue at the terminal side thereof, and subsequently, It is assumed that three 8-bit word synchronization data A2 continue.

Such an additional word data group DW
In the composite 8-bit word string data DZ (8) formed by inserting S into the 8-bit word string data DZ (8), the portion of the composite 8-bit word string data DZ (8) into which the additional word data group DWS is inserted is as shown in FIG. It is said. In FIG. 4, DD8 represents 8-bit word data forming 8-bit word string data DX (8) obtained from the switch 23.

As described above, the composite 8-bit word string data DZ (8) obtained from the switch 24 is derived from the composite word string data forming unit 11 under the condition that the word transmission rate is 77.76 MBps, and is converted into parallel data. / Serial (P / S) converter 27. P / S converter 2
7, the composite 8-bit word string data DZ (8)
P / S that converts parallel data into serial data
After conversion, composite 8-bit word string data DZ (8)
, A bit transmission rate of 77.76 MBps × 8
= 0.622 Gbps, and supplies the serial data DZS to the transmission unit 28.

The transmitting unit 28 converts the serial data DZS into
For example, in order to transmit through a data transmission line formed using a coaxial cable or an optical fiber, an electric signal suitable for a data transmission line formed using a coaxial cable or an optical fiber is used. The signal is converted into a transmission signal SZ which is an optical signal suitable for the data transmission path to be formed and transmitted. Thereby, transmission of the serial data DZS is performed.

FIG. 5 shows an example of a data transmission method according to one of the first to sixth aspects of the present invention. In the data transmission apparatus shown in FIG. Complex 8 sent from
An example of a data receiving device that receives a transmission signal SZ based on serial data DZS obtained by converting bit word string data DZ (8) is shown.

In the example of the data receiving apparatus shown in FIG. 5, the data is transmitted from the transmitting section 28 in the data transmitting apparatus shown in FIG. 1, and is formed using, for example, a coaxial cable or an optical fiber. A receiving unit 31 is provided for receiving the transmission signal SZ transmitted through the data transmission path. The receiving unit 31 transmits the transmission signal S
When receiving Z, the serial data DZS whose bit transmission rate based on the received transmission signal SZ is 0.622 Gbps is reproduced, and the reproduced serial data DZS is reproduced.
Is supplied to a synchronous data detection / serial / parallel (S / P) converter 32.

In the synchronous data detection / S / P converter 32, the supplied bit transmission rate is set to 0.622 Gbp.
In the serial data DZS to be s, a portion where three 8-bit word synchronization data A1 and three 8-bit word synchronization data A2 are converted into serial data is detected as synchronization data, and based on the detected synchronization data. S / P conversion is performed on the serial data DZS with word synchronization to obtain parallel data based on the serial data DZS. The serial data DZ obtained in this manner
For parallel data based on S, the word transmission rate is 7
Composite 8-bit word string data D at 7.76 MBps
Z (8).

The composite 8-bit word string data DZ (8) obtained from the synchronous data detection / S / P converter 32 includes an additional word data group DWS, and is added to the composite 8-bit word string data DZ (8). The portion including the word data group DWS is, for example, as shown in FIG. 6A according to the content of the additional word data group DWS. In the additional word data group DWS, three consecutive 8-bit word synchronization data A1 and three consecutive 8-bit word synchronization data A2 following it are arranged at the beginning and the end, respectively. I have.
Then, the composite 8-bit word string data DZ (8) obtained from the synchronous data detection / S / P converter 32 is supplied to the word data separation / speed converter 33.

The synchronous data detection / S / P converter 32
Detects three consecutive 8-bit word synchronization data A1 and the following three consecutive 8-bit word synchronization data A2 in the additional word data group DWS in the composite 8-bit word string data DZ (8). Then, the word synchronous data detection output signal SWS is transmitted.
The word synchronization data detection output signal SWS is, for example,
Three consecutive 8-bit word synchronization data A1 in the additional word data group DWS in the composite 8-bit word string data DZ (8) detected by the synchronization data detection / S / P conversion unit 32, and successive data following it 3
Of the 8-bit word synchronization data A2, that is, three 8-bit word synchronization data A1 and 3
6 corresponding to the last 8-bit word synchronization data A2 of the 8-bit word synchronization data A2.
B is obtained.

In this way, synchronous data detection / S / P
The word synchronization data detection output signal SWS obtained from the conversion unit 32 is supplied to the control signal forming unit 34. And
In the control signal forming section 34, a synchronization control signal CW based on the word synchronization data detection output signal SWS is formed.

The word data separation / speed conversion unit 33 to which the composite 8-bit word string data DZ (8) is supplied from the synchronization data detection / S / P conversion unit 32 receives the synchronization control signal from the control signal forming unit 34. CW is also provided. In the word data separation / speed conversion unit 33, the word transmission rate is set to 77.76 MBps from the composite 8-bit word string data DZ (8) under the control of the word synchronization by the synchronization control signal CW. The bit word string data DX (8) and the additional word data group DWS are separated and taken out. Further, in the word data separation / speed conversion section 33, the extracted digital bit stream DX (8) is obtained from the amount of data in the portion where the compressed data exists in the compressed digital video signal D (8).
Compressed digital video signal D based on CI
It is determined whether it is based on CP. Then, as a result of the determination, the extracted 8-bit word string data DX
When (8) is based on the compressed digital video signal DCI, the 8-bit word string data DX (8)
And the word transmission rate from 77.76 MBps to 74.
If the transmission rate is converted to 25 MBps, and if the conversion is based on the compressed digital video signal DCP, the word transmission rate of the 8-bit word string data DX (8) is changed from 77.76 MBps to 148.5 MBp.
The transmission rate is converted to s.

As a result, in the word data separation / speed conversion section 33, the additional word data group DWS is extracted, and the word transmission rate is set to 74.25 MB.
The compressed digital video signal DCI of ps or the compressed digital video signal DCP of the word transmission rate of 148.5 MBps is restored, and these are derived from the word data separation / speed conversion unit 33.

In the example shown in FIG. 1 described above, the speed conversion / synchronous data insertion unit 12 has the configuration shown in FIG.
For the bit word string data DX (8), detection of a part where compressed data does not exist following a part where compressed data exists in each frame period, into which the additional word data group DWS from the word data sending unit 13 is to be inserted Is performed by detecting SEC and SHC included in the compressed data in each frame period of the 8-bit word string data DZ (8). The detection of the portion where the compressed data does not exist following the portion where the compressed data exists during the frame period is performed by detecting the portion of the 8-bit word string data DZ (8) included in the compressed data during each frame period as shown in FIG. It is also possible to use a GSC as shown, or a PSC as shown in FIG. 11D.

Further, the 8-bit word string data DX 'is read from each of the memories 20 and 21 shown in FIG.
In reading (8), 8-bit word string data D
A GSC as shown in C of FIG. 11 or a PSC as shown in D of FIG. 11 included in the compressed data in X ′ (8) is detected, and according to the detected GSC or PSC, etc. By controlling the read timing of the 8-bit word string data DX '(8) from each of the memories 20 and 21, the read 8-bit word string data DX' (8) is The existing part is divided so as to sandwich the part where the compressed data does not exist, and the additional word data group DWS from the word data sending unit 13 is inserted into the part where the compressed data does not exist. Is also possible.

[0076]

As is apparent from the above description, in the data transmission method according to any one of the first to sixth aspects of the present invention, the data is to be transmitted. A composite 8 based on a compressed digital video signal forming 8-bit word string data obtained by subjecting a digital video signal, which is converted into serial data and transmitted, to data compression in units of a predetermined section period.
The bit word string data includes 8-bit word synchronization data to which a predetermined code is assigned, and includes the 8-bit word synchronization data to which the predetermined code is assigned. On the receiving side, which receives the composite 8-bit word string data in a state converted to serial data, the 8-bit word synchronization data converts the serial data into parallel data, It is to be properly detected as word synchronization data required for processing for reproducing a compressed digital video signal from column data. Therefore, on the receiving side, a state in which the data synchronization state required for the reproduction processing of the compressed digital video signal based on the received composite 8-bit word string data is reliably obtained.

Therefore, according to the data transmission method according to any one of the first to sixth aspects of the present invention, a data compression process is performed on a digital video signal. The compressed digital video signal is formed into complex 8-bit word string data to which word synchronization data to which a predetermined code is assigned is added based on the compressed digital video signal, and the combined 8-bit word string data is transmitted as serial data. With the transmission method transmitted as much as possible, it is possible to transmit the data so that the data can be reliably reproduced on the receiving side. In addition, when composite 8-bit word string data based on a compressed digital video signal is transmitted as serial data, for example, SDH
An existing IC element or the like, which is to be used, can be effectively used.

According to the data transmission device of the invention described in claim 7 of the present application,
The compressed digital video signal formed by performing data compression processing on the digital video signal by the composite word string data forming means and the data sending means is added with word synchronization data to which a predetermined code is assigned based on the compressed digital video signal. Thus, the received 8-bit word string data is formed, and the 8-bit word string data can be transmitted so as to be surely reproduced on the receiving side by the transmission method of transmitting the serial data.
The data transmission means for transmitting the composite 8-bit word string data based on the compressed digital video signal as serial data is constituted by, for example, an existing IC element or the like effectively used for SDH. Can be made.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a data transmission method according to an embodiment of the present invention; FIG. 1 is a block diagram illustrating a data transmission method according to an embodiment of the present invention; It is a block diagram showing an example of the described data transmission device.

FIG. 2 is a time chart for explaining an example of a data transmission method according to the invention described in any one of claims 1 to 6 in the claims of the present application.

FIG. 3 is a block diagram showing a specific configuration example of a rate conversion / synchronization data insertion unit in the example of the data transmission device shown in FIG. 1;

FIG. 4 is a time chart for explaining one example of a data transmission method according to the invention described in any one of claims 1 to 6 in the claims of the present application.

FIG. 5 shows an example of a data receiving apparatus for receiving a transmission signal transmitted according to an example of the data transmission method according to any one of the first to sixth aspects of the present invention. It is a block block diagram.

FIG. 6 is a time chart for explaining an operation of the example of the data receiving apparatus shown in FIG. 5;

FIG. 7 is a conceptual diagram serving to explain STM-1 used in transmitting digital data.

FIG. 8 shows STM-1 for transmitting digital data.
FIG. 3 is a conceptual diagram serving to explain STM-N obtained by multiplexing.

FIG. 9 is a conceptual diagram illustrating an example of a data format of a digital video signal.

FIG. 10 is a conceptual diagram provided for describing an example of a data format of a digital video signal.

FIG. 11 is a conceptual diagram illustrating an example of a data format of a compressed digital video signal.

[Explanation of symbols]

11: compound word string data forming unit, 12: speed conversion / synchronous data inserting unit, 13: word data sending unit, 18, 23, 24 ... switch, 19 ...
-Switch control signal forming unit, 20, 21 ... memory unit, 22 ... memory control signal forming unit, 25 ...
SHC; SEC detector, 26 ... control signal generator,
27: P / S conversion unit, 28: Transmission unit

Claims (7)

[Claims] An 8-bit word obtained by subjecting a digital video signal to data compression in units of a predetermined section period, wherein a portion where compressed data exists and a portion where the compressed data does not exist are alternately connected. By inserting an additional word data group including 8-bit word synchronization data to which a predetermined code has been assigned into a portion of the compressed digital video signal forming the column data where the compressed data does not exist, the composite 8 A data transmission method for forming bit word string data, converting the composite 8-bit word string data into serial data, and transmitting the serial data for transmission. 2. The data transmission method according to claim 1, wherein the additional word data group is selected to include a portion in which a plurality of the same 8-bit word synchronization data continue. 3. An additional word data group includes a portion where a plurality of first 8-bit word synchronization data are consecutively arranged,
3. The data transmission method according to claim 2, wherein the data transmission method includes selecting a portion including a plurality of second 8-bit word synchronization data different from the 8-bit word synchronization data. 4. An 8-bit word string obtained by subjecting compressed data constituting a compressed digital video signal to data compression by high-efficiency coding on image information data representing a predetermined section period of the digital video signal. 4. The data transmission method according to claim 1, wherein the data is data. 5. An 8-bit word string data obtained by subjecting compressed data constituting a compressed digital video signal to image information data representing each frame period of the digital video signal and performing data compression by high efficiency coding. The data transmission method according to claim 4, wherein: 6. A transmission rate conversion process is performed on a compressed digital video signal prior to inserting an additional word data group into a portion of the compressed digital video signal where no compressed data exists. Data transmission method. 7. An 8-bit word obtained by subjecting a digital video signal to data compression in units of a predetermined section period, wherein a portion where compressed data exists and a portion where the compressed data does not exist are alternately connected. By inserting an additional word data group including 8-bit word synchronization data to which a predetermined code has been assigned into a portion of the compressed digital video signal forming the column data where the compressed data does not exist, the composite 8 Compound word string data forming means for forming bit word string data, and data transmission for converting the compound 8-bit word string data obtained from the compound word string data forming means into serial data and transmitting the serial data Means for transmitting data.