JPS6030473B2 - Frame memory control method - Google Patents
Frame memory control methodInfo
- Publication number
- JPS6030473B2 JPS6030473B2 JP52051979A JP5197977A JPS6030473B2 JP S6030473 B2 JPS6030473 B2 JP S6030473B2 JP 52051979 A JP52051979 A JP 52051979A JP 5197977 A JP5197977 A JP 5197977A JP S6030473 B2 JPS6030473 B2 JP S6030473B2
- Authority
- JP
- Japan
- Prior art keywords
- frame memory
- frame
- encoding
- interframe
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Compression, Expansion, Code Conversion, And Decoders (AREA)
Description
【発明の詳細な説明】
本発明は、フレーム間符号化方式を利用する画像伝送シ
ステムにおいて、誤復号信号の高速復帰を可能にするフ
レ−ムメモリ制御方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frame memory control method that enables high-speed recovery of an erroneously decoded signal in an image transmission system using an interframe coding method.
フレーム間符号化方式は、フレーム間の相関を利用する
ものでで、過去の画像を記憶しておくフレームメモリを
もっており、過去のフレームおよび近傍サンプルの値を
使用して予測信号を合成し、現信号と予測信号間の予測
誤差信号が閥値より大きい部分の画像信号あるいは予測
誤差信号を符号化し、この符号化されたデータ系列に対
し、誤り訂正符号化ならびに誤り検出符号化を行った後
伝送するものである。Interframe coding uses correlation between frames, has a frame memory that stores past images, and synthesizes a predicted signal using values of past frames and neighboring samples. The image signal or prediction error signal of the part where the prediction error signal between the signal and the prediction signal is larger than the threshold value is encoded, and the encoded data sequence is subjected to error correction encoding and error detection encoding before being transmitted. It is something to do.
従って、伝送路で誤りが発生し、この誤りが受信側の誤
り訂正復号化回路で訂正されなかった場合、謀復号が発
生し、送信側のフレーム間符号化装置符号化部のフレー
ムメモリと受信側のフレーム間符号化装置復号部のフレ
ームメモリの内容に違いを生ずる。このため、予測誤差
信号が閥値より大きい部分の画像信号を伝送する方式に
おいては、謀復号された画素が画面の動きにより伝送さ
れる対称画素となるまで、また予測誤差信号を伝送する
方式においてはリフレッシュ信号を送信側のフレーム間
符号化装置符号化部から受信側のフレーム間符号化装置
復号部に送信することにより送信側と受信側のフレーム
メモリの内容が強制的に一致されるまで、誤りの影響が
続く欠点があった。また、伝送路の誤りと等価な画品質
劣化は電源投入時における送信側と受信側のフレームメ
モリの内容の相違、あるいは多者ＴＶ会議方式における
相手局の切替え時の受信映像フレームの跳躍による送信
側と受信側のフレームメモリの内容の相違によっても発
生する。従来のこの種の方式は１フレーム当りｎ本の走
査線をリフレツシュ用走査線とし、該走査線上の画素の
ＰＣＭ信号をリフレッシュ信号として強制的に伝送し、
そのリフレッシュ用走査線の位置を順次シフトすること
により送信側と受信側のフレームメモリの内容を一致さ
せていた。従って、１フレーム当りの走査線数をＮとす
ると、送信側と受信側のフレームメモリ内容の不一致の
影響は最大Ｎ／ｎフレーム期間継続して長時間となるた
め、画品質劣化が強調される欠点があった。本発明は、
上記従来例の欠点を除去するために伝送路での誤りによ
る復号停止や電源投入あるいは多者ＴＶ会議方式におけ
る相手局切替等の際に、その次の映像フレーム同期信号
に続く１フレーム期間は送信側のフレーム間符号化装置
符号化部のフレームメモリに一定値Ｍを書き込み、該一
定値Ｍを受信側のフレーム間符号化袋層復号部で受信す
ることにより、両者の一致をとり、シーンチェンジと等
化な状態にするようにしたフレームメモリ制御方式を提
供するものである。以下、図面により実施例を詳細に説
明する。図は、本発明の−実施例を示す３者ＴＶ会議シ
ステムで、１，２，３はＴＶ会議端末を含む局、４，５
，６はフレーム間符号化端局装置符号化部、７，８，９
はフレーム間符号化端局装置復号部、１川まビデオ切替
部、１１は制御部である。Therefore, if an error occurs in the transmission path and this error is not corrected by the error correction decoding circuit on the receiving side, a false decoding will occur, and the frame memory of the interframe encoder encoding section on the transmitting side and the receiving This causes a difference in the contents of the frame memory of the decoding unit of the interframe encoding device on the side. Therefore, in the method of transmitting the image signal of the part where the prediction error signal is larger than the threshold value, until the decoded pixel becomes the symmetric pixel to be transmitted due to the movement of the screen, and in the method of transmitting the prediction error signal, Until the contents of the frame memories on the transmitting side and the receiving side are forcibly matched by sending a refresh signal from the encoding section of the interframe encoding device on the transmitting side to the decoding section of the interframe encoding device on the receiving side, The drawback was that the effects of the error continued. In addition, image quality deterioration equivalent to errors in the transmission path is due to differences in the contents of the frame memories on the transmitting and receiving sides when the power is turned on, or due to jumps in received video frames when switching between partner stations in a multi-party TV conference system. This can also occur due to differences in the contents of the frame memories on the side and the receiving side. This type of conventional system uses n scanning lines per frame as refresh scanning lines, and forcibly transmits PCM signals of pixels on the scanning lines as refresh signals.
By sequentially shifting the positions of the refresh scanning lines, the contents of the frame memories on the transmitting side and the receiving side are made to match. Therefore, if the number of scanning lines per frame is N, the effect of a mismatch in the frame memory contents on the transmitting side and the receiving side will continue for a maximum of N/n frame periods and will be long, so the image quality deterioration will be emphasized. There were drawbacks. The present invention
In order to eliminate the drawbacks of the conventional example described above, when decoding is stopped due to an error in the transmission path, the power is turned on, or the other station is switched in a multi-party TV conference system, the 1 frame period following the next video frame synchronization signal is transmitted. By writing a constant value M into the frame memory of the encoding unit of the interframe encoding device on the side, and receiving the constant value M by the interframe encoding bag layer decoding unit on the receiving side, a match is made between the two and a scene change is performed. The present invention provides a frame memory control method that achieves an equal state. Hereinafter, embodiments will be described in detail with reference to the drawings. The figure shows a three-party TV conference system showing an embodiment of the present invention, where 1, 2, and 3 are stations including TV conference terminals;
, 6 is an interframe encoding terminal equipment encoding unit, 7, 8, 9
11 is an interframe coding terminal equipment decoding section, a video switching section, and a control section.
次に、この実施例の動作を説明する。まず、各ＴＶ会議
端末は電源の投入に際して、自局のフレーム間符号化端
局装置の符号化部のブレーキメモリに一定値Ｍを書込む
。各フレーム間符号化端局袋暦復号部７，８，９は、受
信されるデータ系列に対し、伝送誤り訂正復号化により
可能な限り誤りを訂正した後、伝送誤り訂正復号化によ
り訂正されない誤りを検出した場合は、伝送誤りを検出
したことを表わす情報を制御部１１に送出する。制御部
１１は各局から送られてくる希望相手局を表わす信号あ
るいは伝送路誤りを検出したことを表わす信号を受信し
、その信号に従ってビデオ切替部１０を制御する。すな
わち、希望相手局をわす信号を受信した場合は要求に応
じた３者間の接続を行うと同時に、切替接続を行ったフ
レーム間符号化機局装置に制御信号を送信し、該フレー
ム間符号化総局装置の符号化部から映像フレーム同期信
号に続く１フレーム期間上記一定値Ｍを送信することに
より、上記符号化部のフレームメモリの内容と、該フレ
ーム間符号化端局装置と通信するフレーム間符号イリ端
局装置復号部のフレームメモリの内容を一致させる。又
、伝送路誤りを表わす情報を受信した場合、制御部１１
は誤りの生じた伝送路を介して通信する送信側端局の符
号化部および受信側端局の復号部に制御信号を送信し、
次にくる映像フレーム同期信号に続く１フレーム期間は
送信側の符号化部から上記一定値Ｍを送信することによ
り送信側符号化部と受信側復号部のフレームメモリの内
容を一致させる。上記の説明では送信側の符号化部のフ
レームメモリの内容と受信側の復号部のフレームメモリ
の内容を一致させる方法として、送信側符号化部のフレ
ームメモリに一定値Ｍを書き込み、それを受信側復号部
で受信する方法について述べた。Next, the operation of this embodiment will be explained. First, when each TV conference terminal is powered on, it writes a constant value M into the brake memory of the encoding unit of its own interframe encoding terminal equipment. Each interframe coding terminal station history decoding unit 7, 8, 9 corrects as many errors as possible by transmission error correction decoding on the received data sequence, and then corrects errors that are not corrected by transmission error correction decoding. If a transmission error is detected, information indicating that a transmission error has been detected is sent to the control unit 11. The control section 11 receives a signal indicating a desired partner station or a signal indicating that a transmission path error has been detected, sent from each station, and controls the video switching section 10 in accordance with the signal. That is, when a signal indicating the desired partner station is received, a three-party connection is established according to the request, and at the same time, a control signal is sent to the interframe encoder station device that has made the switched connection, and the interframe encoder By transmitting the constant value M for one frame period following the video frame synchronization signal from the encoding unit of the video frame synchronization signal, the content of the frame memory of the encoding unit and the frame to be communicated with the interframe encoding terminal equipment are transmitted. The contents of the frame memory of the terminal equipment decoding unit are made to match the contents of the frame memory of the inter-code decoding unit. Further, when information indicating a transmission path error is received, the control unit 11
transmits a control signal to the encoding unit of the transmitting terminal station and the decoding unit of the receiving terminal station communicating via the transmission path where the error occurred,
During one frame period following the next video frame synchronization signal, the constant value M is transmitted from the transmitting side encoding section to match the contents of the frame memories of the transmitting side encoding section and the receiving side decoding section. In the above explanation, as a method of matching the contents of the frame memory of the transmitting side encoding section and the contents of the frame memory of the receiving side decoding section, a constant value M is written in the frame memory of the transmitting side encoding section, and then the received value is The method of receiving the data in the side decoding unit has been described.
なお、送受フレームメモリ内容の一致をとる方法として
は、フレームメモリの入力データをスイッチにより切替
えて一定値Ｍにプリセットする方法、あるいは送信側映
像入力信号を一定値Ｍとし、符号化出力ビット長が最短
となるように符号器をセットすることにり、速度平滑用
バッファメモリがアンダフローする状態にしてアンダフ
ローリフレツシュ信号を大量に送出することにより、両
フレームメモリ内容を一致させる方法等があることは明
らかである。また、制御部１１、ビデオ切替部１０は、
ビデオ交換機および共通線信号装置により構成できるこ
とも明らかである。なお、上記の実施例では、３者ＴＶ
会議システムについて説明したが、多者ＴＶ会議システ
ムについても可能なことは明らかである。In addition, as a method for matching the contents of the transmitted and received frame memories, there is a method in which the input data of the frame memory is switched with a switch and preset to a constant value M, or a method in which the video input signal on the transmitting side is set to a constant value M and the encoded output bit length is set to a constant value M. There is a method of matching the contents of both frame memories by setting the encoder so that the speed smoothing buffer memory underflows and sending out a large amount of underflow refresh signals. That is clear. Further, the control unit 11 and the video switching unit 10
It is also clear that it can be constructed with a video switch and a common line signaling device. In addition, in the above embodiment, three-party TV
Although a conference system has been described, it is clear that a multi-party TV conference system is also possible.
更に、２者間のみのシステムでは、ビデオ切替部１０が
なく回線が接続されたままの状態で上記動作が適用され
得ることは明らかである。以上説明したように、本発明
によれば、送受フレームメモリの内容に不一致が生じた
場合、強制的に両者を一致させるようにし、シーンチェ
ンジと等価な状態にしたため、復号信号はたかだか数フ
レームの短時間で復帰できる利点がある。Furthermore, it is clear that in a system with only two parties, the above operation can be applied without the video switching unit 10 and with the line still connected. As explained above, according to the present invention, when a mismatch occurs between the contents of the transmitting and receiving frame memories, the two are forced to match and the state is equivalent to a scene change. It has the advantage of being able to return to work in a short time.
図は、本発明の一実施例を示す３者ＴＶ会議システムの
ブロック図である。
１，２，３……ＴＶ会議末端を含む局、４，５，６・・
・・・・フレーム間符号化端局装置符号化部、７，８，
９……フレーム間符号化端局装置復号部、１０・・・・
・・ビデオ功替部、１１・・・・・・制御部。The figure is a block diagram of a three-party TV conference system showing one embodiment of the present invention. 1, 2, 3... Stations including the TV conference end, 4, 5, 6...
. . . Interframe encoding terminal station device encoding unit, 7, 8,
9... Interframe coding terminal station device decoding section, 10...
...Video conversion unit, 11...Control unit.
Claims (1)
部とで構成される複数局間の画像伝送システムにおいて
、 受信側のフレーム間符号化装置が伝送路符号誤りを
検出した場合、該受信側のフレーム間符号化装置の属す
る局から前記制御部へ制御信号を送出すること、 該制
御部は、この制御信号を受けて当該受信側のフレーム間
符号化装置と交信している送信側のフレーム間符号化装
置へ該制御信号を転送すること、および 当該送信側の
フレーム間符号化装置は、この制御信号を受けた後、所
定の一定時間の間、自装置の符号化部のフレームメモリ
の内容を所定の値にセツトすることを特徴とするフレー
ムメモリ制御方式。1. In an image transmission system between multiple stations consisting of a plurality of interframe encoding devices, a video switching unit, and a control unit, if the interframe encoding device on the receiving side detects a transmission line code error, the receiving side sending a control signal from a station to which the interframe encoding device belongs to the control unit; Transferring the control signal to the inter-frame encoding device; and After receiving the control signal, the inter-frame encoding device on the transmitting side stores the frame memory of the encoding unit of its own device for a predetermined period of time. A frame memory control method characterized by setting contents to predetermined values.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP52051979A JPS6030473B2 (en) | 1977-05-09 | 1977-05-09 | Frame memory control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP52051979A JPS6030473B2 (en) | 1977-05-09 | 1977-05-09 | Frame memory control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS53137622A JPS53137622A (en) | 1978-12-01 |
| JPS6030473B2 true JPS6030473B2 (en) | 1985-07-16 |
Family
ID=12901971
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP52051979A Expired JPS6030473B2 (en) | 1977-05-09 | 1977-05-09 | Frame memory control method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6030473B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55132182A (en) * | 1979-03-31 | 1980-10-14 | Nec Corp | Coder-decoder for composite difference for television |
| JPH0642735B2 (en) * | 1981-12-28 | 1994-06-01 | 日本電気株式会社 | Predictive coding device |
| JPS61107887A (en) * | 1984-10-30 | 1986-05-26 | Nec Corp | Adaptive type forecasting coding system and device for picture signal |
| JPS62193383A (en) * | 1986-02-20 | 1987-08-25 | Kokusai Denshin Denwa Co Ltd <Kdd> | Moving image signal transmitting system |
| JPS6471391A (en) * | 1987-09-11 | 1989-03-16 | Matsushita Electric Ind Co Ltd | Prediction encoding device |
-
1977
- 1977-05-09 JP JP52051979A patent/JPS6030473B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53137622A (en) | 1978-12-01 |
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