JPH04156193A - Picture transmission system for atm - Google Patents

Abstract

PURPOSE:To suppress increase in transmission information and to correct an error in picture information of a receiver side quickly by processing block information at a coding section when aborted video block information is detected in received information. CONSTITUTION:When information losing consecution is inputted to an entropy coding section 61-2, the presence of an aborted cell is detected on ATM transmission lines 41, 42. Then an aborted block number of the cell and the presence of abort are outputted to a sender side source coder 21-2 and a variable length coding section 22-2 as abort information. A source decoder 62-2 decodes inputted coding information according to the coding system and outputs the decoded signal to a memory 71-2 sequentially. Thus, even when cell abort takes place in the ATM transmission lines 41, 42, a picture block having the aborted cell is refreshed only and the increase in the information quantity to be sent is suppressed and the error is restored quickly.

Description

[Detailed Description of the Invention] [Summary] Regarding the image transmission method in ATM, even if an el, which is a unit of transmission of image information, is discarded on the ATM transmission path, the power of the transmitted information can be suppressed, and the receiving side can A video division process that inputs a video signal, divides one screen of the video signal into double-acting blocks, and outputs each divided video block, with the aim of quickly and efficiently correcting errors in image information. and the video block output from the video division processing section, and encode the video block information of the corresponding block number in μ and `` in the first block corresponding to the encoded information and the block, respectively. When the presence or absence of discarding of the discard information that constitutes the video block information is set to Yes, the video block information is output, and the presence or absence of discard of the discard information that constitutes the video block information received by the decoding unit is set to Yes, The encoder is configured to process the encoded information constituting the video block information of the corresponding block number by intra-frame encoding.

[Industrial application field]

The present invention relates to an image transmission method in ATM, and particularly to a processing method when cells for information transmission are discarded on a transmission path.

When data is discarded, which is unique to ATM transmission, when image information is transmitted, image disturbances (errors) occur on the receiving side. This image disturbance remains on the screen forever in a high-efficiency image encoding device that uses interframe encoding as the encoding method. It is desirable to eliminate this error quickly and while suppressing the increase in the amount of information.

[Conventional technology]

An example of a high-efficiency encoding device (not shown) using the current interframe encoding method will be described.

Normally, image information to be transmitted is encoded, parity pits are added to form transmission image information, and the image information is sent out from an image transmission device. This transmitted image information is received by another image transmission device, which decodes the image information and detects transmission errors using the parity bit added to the image information. The transmission error detected here indicates that there is an error in the received image information. This error is recorded in the image information decoding memory on the receiving side and cannot be eliminated unless the decoding memory is rewritten.

Therefore, in order to eliminate this error, the image encoding device that received the image information sends a demand refresh request to the encoding device that sent the image information. request to send information) and have the sending side send image information that is encoded by the intra-frame encoding method for one screen worth of image information.
The error is corrected by rewriting the information stored in the image information decoding memory on the receiving side.

Moreover, the above-mentioned transmission errors occur only once every several tens of minutes to several hours due to the error correction function.

[Problem to be solved by the invention]

When a high-efficiency encoding device that operates as described above is connected to an ATM (asynchronous transfer mode) transmission line and operated, the image information to be transmitted is divided into cells, which are the units of information transmission on the ATM transmission line. will be sent. However, A
As the axle of the TM transmission line becomes larger (the transmission information exceeds the capacity of the transmission line), data will be discarded one after another.

Due to this data discard, the cell, which is the unit of information transmission, will not be received by the high-efficiency encoding device on the receiving side.

Therefore, errors such as transmission path errors that cannot be corrected by the error correction function frequently occur, and demand refresh requests are frequently made to the high-efficiency image encoding device on the transmitting side. Therefore, the amount of image information to be transmitted increases, the number of screens of image information that can be transmitted decreases over time, and the movement of reproduced images becomes extremely poor.

Therefore, the purpose of the present invention is to suppress the increase in transmitted information and promptly correct errors in image information on the receiving side even when cells, which are units of transmitting image information, are discarded on the ATM transmission line. It is said that

[Means to solve the problem]

FIG. 1 shows a diagram of the principle of the present invention. First, the input video signal is divided into a plurality of blocks by the video division processing section l, and the encoding section 2 encodes each block divided by the video division processing section l. The discard information consisting of the encoded information, the block number corresponding to the block, the presence or absence of discard detected by the receiving unit, and the discard block number is made into one video block information, and the multiplexing unit 3 combines the video block information and the time stamp. A transmitter multiplexes information and other information including audio information and sends it to the ATM transmission line 4, and other information including video block information, time stamp information, and audio signal input from the ATM transmission line 4 is multiplexed. A separating unit 5 separates the information, a decoding unit 6 decodes the encoded information constituting video block information, outputs the discard information to a transmitting unit, and a video synthesis processing unit 7 decodes the information. It has a receiving section that synthesizes the video blocks for one screen and outputs it as a video signal, and detects the presence of discarded video block information in the received information based on the time stamp information separated by the separating section 7. In this case, the encoding unit sets whether or not to discard the discard information that constitutes the video block information of the corresponding block number, and the decoder 7 sets whether or not to discard the discard information that constitutes the input video block information. When it is set as "Yes", the encoding unit processes the encoded information forming the video block information of the corresponding block number by intra-frame encoding.

[Effect]

According to the present invention, the encoding unit adds the presence or absence of discard in the receiving unit and the block number of the image block to be transmitted,
Since the multiplexer multiplexes the time stamp information that is sequentially added to the cells to be transmitted, the receiver receives discarded information when there is discarded information among the received information.
Discarding is detected when the continuity of the timestamp added to each cell is lost, and the result is written in the discard information of the corresponding block number in the encoder, and the cell with the block number corresponding to the source of the image is discarded. The transmission source of the image that receives the notification processes the video block of the corresponding block number by intraframe encoding processing and transmits the video information.

Therefore, on the receiving side, it is possible to know which blocks of the received video blocks have been discarded, and on the transmitting side, it is now possible to know from the receiving unit which image blocks have been discarded.

〔Example〕

Embodiments of the present invention are shown in FIGS. 2 to 5.

The video division processing unit l in FIG. 1 is the A/D converter 11 in FIG.
-1.2, Preprocessing section 12-1.2, Memo January 3-1.2
The encoding section 2 in FIG. 1 corresponds to the section consisting of the source coder 21-1.2 and the entropy encoding section 22-1.2 in FIG. The multiplexer 3 in the figure is the cell multiplexer 31-1.2 in FIG. 2, the transmission line interface (hereinafter referred to as INF) 32-1.
The ATM transmission line 4 in FIG. 1 corresponds to the part consisting of the uplink 41 and the downlink 42 in FIG. Transmission line interface (hereinafter referred to as INF) 51-1.2 in the figure
, cell separation unit 52-1.2, and the decoding unit 6 in FIG. 1 includes entropy decoding units 61-1.
2. The video synthesis processing section 7 in FIG. 1 corresponds to the part consisting of the source coder 62-1.2, and the memory 71 in FIG.
-1.2, post-processing section 72-1.2, D/A converter 73-
1.2.

In the figure, a video signal is first input to an A/D converter 11-1, converted to a digital video signal, and then sent to a preprocessing section 12.
-1 can be input. In the preprocessing section 12-1, the input digital video signal is separated into color/luminance, band-limited, and input into the memory 13-1. Memo January 3-1, when the input video signal is accumulated for one screen, it is divided into multiple blocks, for example 1 to X, as shown in Fig. 3, and each block is output to the source coder 21-1. are doing. Depending on the discard information (presence of discard, block number) input from the source decoder 62-1 of the receiving section, whether to use the intra-frame encoding processing method or the inter-frame encoding method is input for each block. The video signal of each block is encoded and output to the entropy encoder 22-1. The entropy encoding unit 22-1 subjects the input encoded information to variable length encoding processing, and then converts the input encoded information into frame bits, block numbers, whether or not to discard data, and variable length encoded block data as shown in FIG. The video block information frame is output to the cell multiplexing section 31-1 as a video block information frame composed of .

The cell multiplexer 31-1 multiplexes the input video block information, frame and time stamp information 2, destination address information, and audio data, which is a unit of data to be sent to the ATM transmission line 4 as shown in FIG. The information divided into cells is transmitted to the AT via the transmission path NF32-1.
It is output to the uplink 41 of the M transmission path. Here, the time stamp information is continuous information indicating the order of cell-formed information, and if the cells are not discarded on the transmission path, the receiving side similarly outputs the information as continuous information.

On the receiving side, information that has been converted into cells from the uplink 41 of the ATM transmission line is sent to the cell separation unit 5 via the transmission line NF31-2.
2-2 is input. The cell separation unit 52-2 separates the input cell information into video block information, frame and time stamp information, destination address information, and audio data, and converts the video block information, frame and time stamp information into entropy codes. It is output to the conversion section 61-2.

The entropy decoding unit 61 - 2 performs variable length decoding processing on sequentially input video block information, and the source decoder 62
-2.

In addition, the entropy encoding unit 61-2 checks the continuity of time stamp information, and when information lacking in continuity is input, it detects that a cell has been discarded on the ATM transmission path, and detects the discarded cell. At the time of detection, information omission is detected in the image block information for which variable length decoding processing is being performed. Here, the source coder 21 on the transmitting side informs the discarded block number of the cell and the presence or absence of discard (here, yes).
-2 and outputs the discard information to the variable length encoder 22-2. The source decoder 62-2 decodes the input encoded information according to the encoding method, and sequentially decodes the input encoded information into the memo 1J71-
Output to 2. The memory 71-2 outputs the input image information to the post-processing section 72-2 when it has been accumulated for one screen.

The post-processing unit 72-2 synthesizes the color/luminance signals of the input image information and outputs the synthesized signal via the D/A converter 73-2.

The above operation similarly operates on the downlink.

In other words, when information such as an image sent from station A is discarded, station B, the transmission destination, adds information on whether or not to discard it to the image information with the same block number as the image block that was discarded.
By transmitting the data to the station, station A can determine which block among the transmitted image blocks has been discarded. Therefore, by performing intra-frame encoding processing on only the information of the discarded image block. Just send it.

〔Effect of the invention〕

As described above, in the present invention, even if a cell is discarded on an ATM transmission path, the amount of information to be transmitted can be reduced by refreshing only the image block containing the discarded cell (intraframe encoding processing). This makes it possible to suppress the increase in errors and quickly recover from errors.

[Brief explanation of drawings]

Figure 1 is a diagram of the principle of the present invention, Figure 2 is an embodiment of the present invention, Figure 3 is a diagram of one screen divided into multiple blocks, Figure 4 is a video block information frame, and Figure 5 is cell formation. In the figure, 1... Video division processing section 2... Encoding section 3... Multiplexing section 4... ATM transmission line 5... Separation section
6...Decoding unit 7...Composition processing unit

Claims (1)

[Claims] AT that divides information to be transmitted into multiple cells and transmits
In an image transmission system in M (asynchronous transfer mode), a video division processing unit (1) receives a video signal, divides one screen of the video signal into a plurality of blocks, and outputs each divided video block. , the video blocks outputted by the video division processing unit (1) are each encoded, and a discard consisting of the encoded information, the block number corresponding to the block, the presence or absence of discard detected by the receiving unit, and the discard block number is generated. Information 1
an encoding unit (2) that outputs the video block information as one video block information, and a multiplexing unit (4) that multiplexes the video block information, time stamp information, and other information including audio information and sends the information to the ATM transmission line (4). 3), and inputs information in which video block information, time stamp information, and other information including audio information are multiplexed from the ATM transmission line (4), and transmits video block information and other information. Separation unit (5) that separates and outputs time stamp information and other information including audio information
a decoding unit (6) that separates the separated video block information into encoded information and discard information, outputs the discard information to the transmitter, and decodes and outputs the encoded information; The receiving section includes a video synthesis processing section (7) that receives the encoded video blocks input from the section (6), synthesizes the video blocks for one screen, and outputs the resultant video signal as a video signal. When the decoding unit (6) detects from the time stamp information separated by the separating unit (5) that discarded video block information exists in the video block information, the encoding unit (
2) sets whether or not to discard the discard information that constitutes the video block information of the corresponding block number, outputs the video block information, and at the same time outputs the video block information received by the decoding unit (6). When the discard information that constitutes the discard information is set to "Yes",
An image transmission system in ATM, characterized in that an encoding unit (2) processes the encoded information constituting video block information of a corresponding block number by intraframe encoding.