WO2011012009A1

WO2011012009A1 - Method, device and system for error control in wireless video communication system

Info

Publication number: WO2011012009A1
Application number: PCT/CN2010/072955
Authority: WO
Inventors: 梁立伟; 王宁; 左雯; 范文杰; 黄晓红
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-07-29
Filing date: 2010-05-19
Publication date: 2011-02-03
Also published as: CN101990092B; CN101990092A

Abstract

The present invention discloses a method for error control in a wireless video communication system. The method includes the following steps: a first user terminal receives and decodes the wireless video data transmitted by a second user terminal; when determining a decoding error in the wireless video data transmitted by the second user terminal according to the decoding result, the user terminal transmits to the second user terminal a message for indicating the implementation of error control, and implements local error control. The present invention also discloses a wireless video communication system and a user terminal. By the invention, the error control time of the wireless video communication system is greatly shortened, and system execution efficiency of error control procedure is increased, and thus the error propagation time of the wireless video data is greatly reduced, and the quality of wireless video data is improved, and further the quality of service of the wireless video communication system is efficiently improved, and the user experience is enhanced.

Description

Method, device and system for error control in wireless video communication system

The invention belongs to the field of wireless video communication, and particularly relates to a method, device and system for error control in a wireless video communication system. Background technique

In the wireless transmission environment, due to shadows, multipath fading and other interference factors, wireless signal instability and transmission quality degradation are likely to occur, especially the transmission of video data, which is more susceptible to external factors. For example, in a motion compensation based video coding algorithm, most video frames have a high correlation with the previous frame, and any frame error will be propagated and spread to subsequent frames, causing a serious degradation of video quality.

In the current H.324-M specification used by the 3G standard, it is stipulated that when a receiving end encounters a video decoding error, it may send a VFU (Video Fast Update) request to the transmitting end to request a video key frame to be transmitted (ie, I frame) is refreshed, so that the diffusion of the video decoding error at the receiving end can be effectively improved and controlled.

For example, as shown in Figure 1, the video transmission delays of the mobile phones Β and Β are both T1, so that the video frame a sent by the mobile phone A at the video frame time (ie, the Fal time) can be used by the mobile phone B in the Fb2 after the T1 time. At the same time, the video frame is received and video decoding. Similarly, the video frame b2 sent by the mobile phone B at the time of Fb2 also needs to pass the T1 time, and is received by the mobile phone A at the time of Fa3 and decoded. If the mobile phone A finds that the video data contained in the video frame b2 has an error during video decoding (this error may be generated at the transmitting end of the mobile phone B, or may be generated at the receiving end of the mobile phone A), then the mobile phone A sends The VFU requests to the mobile phone B. Assuming that the transmission delay of the VFU request is T2, after receiving the VFU request, the mobile phone B forces the video frame b4 to perform an I frame refresh at the time of Fb4, that is, re-programs the I frame to perform the previously generated error. Isolated, and to mobile phone A Resend the newly re-edited I-frame video frame b4. The video frame b4 is re-programmed by the T1 delay and arrives at the mobile phone A after the T1 delay. As shown in Figure 1, the mobile phone A will receive the mobile phone B at the time of Fa5. Re-edit the I frame and resume normal video communication.

It can be seen from the above process that it is necessary to detect the V2 response from the mobile phone A to the mobile phone B, to send the VFU request to the mobile phone B, and then to receive the VFU response carrying the re-programmed I frame, which requires a total time of T1 + T2. During this time period, the mobile phone B will still send video data to the mobile phone A, and these subsequent transmitted video data may be affected by the error of the video frame b2, and thus the video decoding image error also occurs; thus, the mobile phone A is The quality of the received video data has an impact, especially when the values of T1 and T2 are large, the effect of this effect is more obvious, and the duration of the impact is relatively long, thus seriously reducing the service of the wireless video communication system. Quality (QoS, Quality of Service). Summary of the invention

In view of this, embodiments of the present invention provide a method, apparatus, and system for error control in a wireless video communication system, which are used to improve the execution efficiency of an error control process when an error occurs in wireless video data transmission.

The specific technical solutions provided by the present invention are as follows:

A method for error control in a wireless video communication system, comprising:

The first user terminal receives the wireless video data sent by the second user terminal and decodes the received wireless video data;

Determining, by the first user terminal, that the wireless video data sent by the second user terminal has a decoding error according to the decoding result;

The first user terminal transmits a message for instructing to implement error control to the second user terminal, and performs error control locally.

A first user terminal in a wireless communication system, comprising:

a receiving unit, configured to receive wireless video data sent by the second user terminal; a decoding unit, configured to decode the received wireless video data, and determine, according to the decoding result, whether the wireless video data sent by the second user terminal has a decoding error;

a first processing unit, configured to: when the decoding unit determines that there is a decoding error in the wireless signal sent by the second user terminal, generate a message sent to the second user terminal to indicate that error control is implemented;

a second processing unit, configured to implement error control locally;

And a sending unit, configured to send, to the second user terminal, the message used to indicate that error control is implemented.

A wireless video communication system, comprising: a first user terminal and a second user terminal, when the first user terminal receives the wireless video data sent by the second user terminal, and confirms that the received wireless signal has a decoding error, The second user terminal transmits a message indicating that error control is implemented, and performs error control locally.

In the embodiment of the present invention, the above technical solution greatly shortens the time used for error control of the wireless video communication system, improves the execution efficiency of the error control process of the system, thereby greatly shortening the error diffusion time of the wireless video data, and improving the wireless The quality of the video data, which effectively improves the quality of the wireless video communication system and enhances the user experience. DRAWINGS

1 is a schematic diagram of wireless video communication in the prior art;

2A is a structural diagram of a wireless video communication system according to an embodiment of the present invention;

2B is a structural diagram of a function of a user terminal according to an embodiment of the present invention;

3A is a flowchart of wireless video communication in an embodiment of the present invention;

FIG. 3B is a schematic diagram of wireless video communication according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The technical solutions of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments. In the wireless video communication system, in order to improve the execution efficiency of the error control process when an error occurs in the wireless video data transmission, in the embodiment of the present application, the first user terminal in the wireless communication system receives the wireless video data sent by the second user terminal. And decoding the second user terminal according to the decoding result, when the wireless video data sent by the second user terminal has a decoding error, sending a message (VFU request) for indicating error control to the second user terminal, and Error control is implemented locally.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 2A, in the embodiment of the present application, a plurality of user terminals in the wireless video communication system are described below, and the user terminal is a mobile phone as an example. As shown in FIG. 2A, in the embodiment of the present application, any mobile phone receives another When the wireless video data transmitted by a mobile phone confirms that the wireless signal has a decoding error, a message for instructing to implement error control is transmitted to the other mobile phone, and error control is implemented locally.

Referring to FIG. 2B, in the embodiment of the present application, the first user terminal in the wireless video communication system includes a receiving unit 200, a decoding unit 201, a first processing unit 202, a second processing unit 203, and a sending unit 204, where:

The receiving unit 200 is configured to receive wireless video data sent by the second user terminal.

The decoding unit 201 is configured to decode the received wireless video data, and determine, according to the decoding result, whether the wireless signal sent by the second user terminal has a decoding error;

The first processing unit 202 is configured to: when the decoding unit 201 determines that the wireless signal sent by the second user terminal has a decoding error, generate a message (VFU request) sent to the second user terminal to indicate that the error control is implemented;

a second processing unit 203, configured to implement error control locally;

The sending unit 204 is configured to send the message to the second user terminal to indicate that the error control is implemented.

Based on the above system architecture, this embodiment uses video data exchanged between mobile phone A and mobile phone B as For example, referring to FIG. 3A and FIG. 3B, in this embodiment, when an error occurs in a video frame sent by the mobile phone, the detailed process of error control by the mobile phone B is as follows:

Step 300: The mobile phone A sends a video frame al to the mobile phone B at the time of Fal.

Step 301: The mobile phone B receives the video frame al transmitted by the mobile phone A at the time of the Fb2, and finds that the video data included in the video frame al has a decoding error, for example, packet loss, error code, frame loss, and the like.

As shown in FIG. 3B, in the embodiment of the present application, the time interval between the H殳 Fal time and the Fb2 time is T1, and then the video frame al is received from the mobile phone B after the T1 delay of the video frame al transmitted by the mobile phone A.

Step 302: At time Fb2, after decoding the video frame, the mobile phone B immediately sends a VFU request b to the mobile phone A, and the following tube is called VFU b; at this time, the mobile phone B also sends the video frame b2 of the Fb2 time to the mobile phone A.

As shown in Fig. 3B, assuming that the transmission delay of the VFU request is T2, and T2 < T1, then the handset 接收 will receive VFU b at time Fa4 and receive video frame b2 at time Fb5.

Step 303: After the mobile phone B determines that the video frame sent by the mobile phone A has an error, the error control is started locally.

In practical applications, when the network signal in the wireless communication system is not good, the signal transmission and signal reception of a single mobile phone are usually affected. For example, in a Time Division Synchronized Code Division Multiple Access (TD-SCDMA) system, different uplink time slots of the same frequency point are used to divide the uplink and downlink physical channels according to the communication standard, so that The correlation of the impulse response of the uplink and downlink physical channels at adjacent moments will be reluctantly. That is to say, in two mobile phones with established communication connections, once a transmission error occurs in one direction, the other direction usually usually A transmission error has occurred.

In view of this, in the embodiment of the present application, when the mobile phone B finds that the video frame a sent by the mobile phone A has a decoding error, immediately considers that the video frame sent by the mobile phone B to the mobile phone A also occurs. The frequency decoding error causes the error control means to be taken immediately without waiting for receiving the VFU request returned by the handset A.

In this embodiment, the method for performing error control by the mobile phone B includes, but is not limited to, the following: forcibly encoding an I frame, updating an I block, reducing a code rate, reducing a frame rate, selecting a frame, and the like, which may be the foregoing multiple methods. One or a combination of these may not be repeated here.

Step 304: The mobile phone B sends the video frame b3 prepared by the error control to the mobile phone A at the time of Fb3.

As shown in FIG. 3B, after a T1 delay, the mobile phone A will receive the video frame b3 at the time of Fa6; at this time, since the video frame b3 is already a video frame re-programmed after the error control of the mobile phone B, therefore, The problem of poor wireless signal quality in the wireless video communication system has been initially solved. The quality of the wireless video data received by the mobile phone A by the mobile phone A has been restored to normal in the single direction of the mobile phone B at the time of the Fa6.

Step 305: The mobile phone A receives the VFU b sent by the mobile phone B at the time of Fa4, and starts the error control locally.

In this embodiment, the means for performing error control by the mobile phone A includes but is not limited to the following: forcibly encoding the I frame, updating the I block, reducing the code rate, reducing the frame rate, selecting the frame selection, etc., may be in the above multiple methods. One or any combination of these will not be repeated here.

Step 306: The mobile phone A will send the video frame a4 prepared after the error control to the mobile phone B at the time of Fa4.

Step 307: After the T1 delay, the mobile phone B receives the video frame a4 at time Fb7, as shown in FIG. 3B.

At this point, the video transmission data of the mobile phone A transmission direction has also returned to normal, and the quality of the wireless video signal between the mobile phone A and the mobile phone B has been completely restored.

Based on the above embodiment, in step 302, since the mobile phone B sends the video frame b2 to the mobile phone A according to the standard protocol, after the mobile phone A receives the video frame b2 at the time of Fa5, if If there is a decoding error in the fixed video frame b2, the VFU request (hereinafter referred to as VFU a ) is sent to the mobile phone B at the time of Fa5, and the mobile phone B is requested to perform error control, and the mobile phone B receives the VFU a at the time Fb7 of the T2 delay from the time of the Fa5. At this time, since the mobile phone B has implemented error control at the time of Fb3, and normal video communication is restored in one direction, the mobile phone B can selectively process the received VFU a request, so-called selective processing, that is, It means that according to the actual environment, mobile phone B can implement error control again for optimizing video data, and can also abandon VFU a processing in order to save system resources, because mobile phone B transmits wireless video data in one direction at the time of Fa6 ( As shown in FIG. 3B, the Fb6 time corresponding to the B side of the mobile phone is restored to normal. Of course, the premise that the mobile phone B is allowed to not process the received VFU a is: the time between the time when the VFUa is received and the time when the mobile phone B last performs the error control is within the set time range, if the two times are too long, Then, after receiving the VFU a, the mobile phone B must implement error control again to ensure the transmission quality of the wireless video data, and details are not described herein again.

Obviously, by adopting the above method, the time used for error control of the wireless video communication system is greatly shortened, the execution efficiency of the error control process of the system is improved, the time of error propagation of the wireless video data is shortened, and the transmission quality of the wireless video data is improved. For example, as shown in FIG. 3B, if the mobile phone B receives the VFUa at the time of Fb7 and then performs error control, the re-encoded video frame needs to be transmitted to the mobile phone A at the time of the F1 delay T1, then the mobile phone The two-way transmission of the wireless video data between the A and the mobile phone B needs to be restored to normal at the time of the Fa8. With the technical solution provided by the present invention, the mobile phone B starts to implement the error control when it finds that the video frame transmitted by the mobile phone A is in error. The video communication on the A side of the mobile phone has returned to normal at the time of Fa6, and the video communication on the B side of the mobile phone has also returned to normal at the time of Fb7. The implementation of the error control flow of the mobile phone A is shortened compared with the prior art (Tl + T2 - 1 ) The time period, which for the wireless video communication system, has significantly shortened the execution time, thereby greatly reducing the possibility that the video frame in which the error occurs affects other video frames in the system, and effectively improving the service of the wireless video communication system. Quality, improved user experience. The type does not depart from the spirit and scope of the invention. Thus, the present embodiments of the invention are intended to cover such modifications and alternatives,

Claims

Claim

A method for error control in a wireless video communication system, the method comprising:

The first user terminal receives the wireless video data sent by the second user terminal, and decodes the received wireless video data;

When the first user terminal determines that there is a decoding error in the wireless video data sent by the second user terminal according to the decoding result, the first user terminal sends a message for instructing to implement error control to the second user terminal, and performs error control locally.

The method according to claim 1, wherein the first user terminal receives the indication sent by the second user terminal during the set time period after the local user performs the error control. The message of error control discards the received message.

3. The method according to claim 1 or 2, wherein the implementing error control comprises forcibly encoding one of a video key frame, a video key frame refresh, a reduced code rate, a reduced frame rate, and a reference frame selection or random combination.

A first user terminal in a wireless communication system, comprising: a receiving unit, configured to receive wireless video data sent by a second user terminal;

a decoding unit, configured to decode the received wireless video data, and determine, according to the decoding result, whether the wireless video data sent by the second user terminal has a decoding error;

a second processing unit, configured to implement error control locally;

The user terminal according to claim 4, wherein the first processing unit enters One step is, after the local implementation of the error control is completed, if the message sent by the second user terminal to indicate the implementation of the error control is received by the receiving unit, the received message is lost. abandoned.

The user terminal according to claim 4 or 5, wherein the second processing unit is further configured to perform forced coding of a video key frame, a video key frame refresh, and a reduced code rate when performing error control. Decrease one or any combination of frame rate and reference frame selection.

A wireless communication system, comprising a first user terminal and a second user terminal, wherein the first user terminal receives the wireless video data sent by the second user terminal, and confirms that the received wireless video data is decoded. In the event of an error, a message indicating the implementation of error control is sent to the second user terminal and error control is implemented locally.

The system of claim 7, wherein the first user terminal is further configured to: after receiving the error control locally, in the set time period, if the second user terminal receives the The message used to indicate the error control is implemented, and the received message is discarded.

The system according to claim 7 or 8, wherein the first user terminal is further configured to perform forced coded video key frame, video key frame refresh, reduce code rate, and reduce when performing error control One or any combination of frame rate and reference frame selection.