WO2009121274A1

WO2009121274A1 - A coding method, device and a switching system for media stream

Info

Publication number: WO2009121274A1
Application number: PCT/CN2009/070972
Authority: WO
Inventors: 郑若滨; 史永懋; 张民; 陈雪
Original assignee: 华为技术有限公司
Priority date: 2008-03-31
Filing date: 2009-03-24
Publication date: 2009-10-08
Also published as: CN101552920A; CN101552920B

Abstract

A coding method, device and a switching system for media stream are provided, wherein, the coding method for media stream comprises analyzing the audience rating information for at least two channels and generating the analyzing result; adjusting the frame interval value of the frame to be inserted in the video stream according to the analyzing result; coding the said video stream according to the frame interval value of the frame to be inserted, in order to carry out the decoding switching for the said video stream. The above coding method, device and switching system for media stream can greatly reduce the waiting time of the reference image, so greatly reduce the time delay of channel switching.

Description

Media stream coding method, device and switching system The application is filed on March 31, 2008, the Chinese Patent Office, the application number is 200810103136.X, the invention name is "media stream coding method, device and switching system" Chinese patent application Priority is hereby incorporated by reference in its entirety. Technical field

The embodiments of the present invention relate to the field of communications technologies, and in particular, to a media stream encoding method, apparatus, and switching system. Background technique

With the deployment of third-generation mobile communication technology (3G) and the convergence of fixed mobile networks, mobile video will be more developed and applied. Mobile video services are new mobiles that transmit video content to mobile users through mobile networks and mobile terminals. Business, this mobile video service can be implemented in three different ways: Based on satellite network implementation, using digital terrestrial broadcasting to implement and utilize mobile network.

Among them, the mobile network implementation method is mainly based on the Wideband Code Division Multiple Access (WCDMA) / Global System for Mobile Communications (GSM) Global Standards Organization, Third Generation Mobile Communication Partner Organization (3GPP) proposed multimedia broadcast multicast service ( MBMS)'s streaming media technology mainly uses streaming media technology to promote mobile TV as a data service. This method can provide users with more personalized services by using the interactive features of the communication network without changing the basic network structure. It is more convenient to implement.

At present, the mobile TV service launched in China mainly relies on the existing mobile network. The fixed network IPTV switching delay is 1.5 seconds to 5 seconds, and mobile video will generate more delay according to network conditions. The switching time of traditional TV is only about 300ms. Compared with traditional TV, mobile video has a long switching time, which will become a flaw in its application, which greatly limits business promotion and business innovation. At present, methods for reducing channel switching time mainly include multicast stream fast leaving, additional channel switching stream images, and adjacent channel preset Internet Group Management Protocol (IGMP) messages. In addition, there are static channel join groups and channel push methods based on the audience rating model. In the process of implementing the present invention, the inventors have found that the prior art has at least the following problems:

The above methods are mostly used for IPTV, and are not suitable for channel switching of mobile video. The switching delay of mobile video mainly includes network delay, buffer time, reference image waiting time and decoding time. In its total channel switching time, the reference image waiting time occupies a large proportion in the total switching time. Therefore, in combination with the MBMS network architecture, there is an urgent need for techniques that reduce reference picture latency to reduce channel switching delays. Summary of the invention

Embodiments of the present invention provide a media stream encoding method, apparatus, and switching system to reduce reference picture latency and thereby reduce channel switching delay.

An embodiment of the present invention provides a media stream coding method, where the method includes: analyzing audience rating information of at least two channels, and generating an analysis result; and adjusting a frame interval value of a frame to be inserted in the video stream according to the analysis result; And encoding the video stream according to a frame interval value of the to-be-inserted frame, so as to perform decoding switching on the video stream.

An embodiment of the present invention provides a media stream encoding apparatus, where the apparatus includes: an analyzing unit, configured to analyze the received rating information of each channel, and generate an analysis result;

And an adjusting unit, configured to adjust, according to the analysis result, a frame interval value of a frame to be inserted in the video stream;

And a processing unit, configured to encode the video stream according to a frame interval value of the to-be-inserted frame. An embodiment of the present invention provides a media stream switching system, including a video head end, a rating unit, and a user access end.

The audience rating unit is configured to analyze the audience rating information of two or more channels to generate an analysis result;

The video head end is configured to adjust a frame interval value of a frame to be inserted in the video stream according to the analysis result obtained by the audience rating unit, and encode the video stream according to the frame interval value of the frame to be inserted; Line decoding switching.

Compared with the prior art, the media stream encoding method, device, and switching system of the embodiment of the present invention send statistical rating information to a video head end, and the video head end analyzes the channel to perform frequent channel switching. With more SP frames, the reference image latency can be greatly reduced, thereby reducing the switching delay of the channel.

The technical solutions of the embodiments of the present invention are further described in detail below through the accompanying drawings and embodiments. DRAWINGS

1 is a flowchart of an embodiment of a media stream encoding method according to the present invention;

2 is a schematic structural diagram of an embodiment of a media stream encoding apparatus according to the present invention;

FIG. 3 is a schematic structural diagram of an embodiment of a media stream switching system according to the present invention. detailed description

As shown in FIG. 1 , it is a flowchart of an embodiment of a media stream encoding method according to the present invention, where the method includes:

Step 101: The radio network controller collects the rating information of the at least two channels and sends the information to the video head end. The paging channel or the broadcast channel requires the terminal that is using a certain MBMS service to send the reply information. When the radio network controller (RNC) receives the reply message sent by the terminal, it calculates and updates the rating information of the channel in real time, and sends the information. To the video headend; the concept of average ratings is used in the rating information here, that is, the ratio of viewers who watch a certain column (or a certain channel) in a certain period of time to the total number of TV viewers in the analysis area; 102. The video head end analyzes the received rating information of each channel, and generates an analysis result.

Before performing the step, the video head end further includes: obtaining the audience rating information of the channel, where the obtaining manner includes: collecting the rating status of the channel reported by the user terminal, obtaining the rating information of the channel, or obtaining the rating of the channel from another device. information.

The analyzing the received audience rating information and transmitting the analysis result specifically includes: dividing the channel whose audience rating is greater than the first threshold into a frequently switched channel; dividing the channel whose audience rating is less than the second threshold into infrequently switching channels; The channel whose rate is greater than or equal to the second threshold is less than or equal to the first threshold is divided into a stable switching channel, and the divided result is sent; wherein the first threshold or the second threshold may be set as needed; the first threshold is greater than the second threshold;

Step 103: Adjust, according to the foregoing analysis result, a frame interval value of a frame to be inserted in the video stream.

According to the degree of channel switching, a different number of Switching Predictive (SP) frames need to be inserted in the video stream. When the video stream is a video stream that frequently switches channels, the first predetermined value SP frame is inserted; when the video stream is When the video stream of the channel is stably switched, a second predetermined value of SP frames is inserted; when the video stream is a video stream that infrequently switches channels, a third predetermined value of SP frames is inserted; the first predetermined value, the second predetermined value, and The third predetermined value may be set as needed, wherein the first predetermined value is greater than the second predetermined value, and the second predetermined value is greater than the third predetermined value;

Step 104: Compile the video stream according to the frame interval value of the frame to be inserted. a code, and sending the encoded video stream to the user terminal;

According to the set number of SP frames to be inserted, the SP frame is inserted into the above video stream; in addition, if the video stream is transmitted over a short distance, an I frame may be inserted in the video stream; if it is stored and retransmitted in the server first That is, when there is a large-capacity storage space, the SI frame can be multi-coded. The specific coding method can be determined according to the actual situation, but the waiting reference frame time is irrelevant, and only relates to the frame insertion period. Finally, the video head end will be encoded. The subsequent video stream is sent to the user terminal by means of IP multicast;

In addition, the above SP frame can provide seamless switching points like I frames, thereby achieving seamless connection between code streams, but in the case of providing the same function, the encoding efficiency of the SP frame is higher than the encoding efficiency of the I frame, and Because of this feature, the SP frame can replace the I frame, which is widely used in inter-stream switching, and greatly reduces the code rate overhead. Meanwhile, when the switching between different code streams is to be realized, the use of the SI frame is also very effective;

Step 105: The user terminal performs decoding switching on the received encoded video stream. After the user terminal receives the video stream sent by the video head end, the video stream is decoded and switched; wherein the video stream is encoded by the video head end according to the rating information sent by the terminal side, and the foregoing encoding is performed after receiving The decoding of the video stream includes: when the received encoded video stream is an I frame, the video stream is directly decoded; when the received encoded video stream is a Switch Intra-Frame (SI) frame At the same time, the above video stream is switched between streams; but in either case, the code stream of the new channel can be immediately decoded for viewing.

The media stream coding method is configured to send the audience rating information of each channel in real time to the video head end, so that the video head end can analyze the channel, and according to the analysis result, insert more SPs into frequently switched channels. The frame can greatly reduce the reference image waiting time, thereby reducing the switching delay of the channel. In addition, the video head end can also directly obtain the rating information of each channel by using a paging channel or a broadcast channel.

FIG. 2 is a schematic structural diagram of an embodiment of a media stream encoding apparatus according to the present invention, where The device includes: an analyzing unit 21, configured to analyze the received rating information of each channel to generate an analysis result; and an adjusting unit 22, configured to adjust a frame interval value of the frame to be inserted in the video stream according to the analysis result; The unit 23 is configured to encode the video stream according to a frame interval value of the to-be-inserted frame.

The media stream coding apparatus further includes: a statistics unit, configured to collect the audience rating information of the channel reported by the user terminal, obtain the audience rating information of the channel, or obtain the audience rating information of the channel from another device; wherein the information includes The service information and the command information, where the service information includes a geographical range, an IP multicast address, a service start time, and the like.

In addition, the foregoing analysis module includes: a dividing module, configured to divide a channel whose viewing rate is greater than the first threshold into a frequently switched channel, and divide the channel whose viewing rate is less than the second threshold into infrequently switching channels, and the viewing rate is greater than or equal to the second The channel whose threshold is less than or equal to the first threshold is divided into stable switching channels; the first threshold is greater than the second threshold; the adjusting unit includes an adjusting module, configured to insert the first when the video stream is a video stream that frequently switches channels a predetermined value of SP frames; when the video stream is a video stream of a stable switching channel, setting a second predetermined value of SP frames; when the video stream is a video stream of infrequently switching channels, setting a third predetermined value of SP frames The processing unit includes: an encoding module, configured to insert a third predetermined value SP frame for infrequently switching channels, and encode the secondary frame in the video stream into an SI frame; wherein, the first predetermined value is greater than the second predetermined value The second predetermined value is greater than the third predetermined value.

The media stream encoding device divides the channel into frequent switching channels, infrequently switching channels, and stably switching channels through the analyzing unit, and simultaneously inserts more SP frames into the frequently switched channel by the adjusting unit, and the processing unit Different types of channels are inserted into different SP frames, and the secondary frames are encoded into SI frames, which greatly reduces the waiting time of the reference image, thereby reducing the switching delay of the channels, and better switching between different code streams.

As shown in FIG. 3, it is a schematic structural diagram of an embodiment of a media stream switching system according to the present invention. The system includes: a rating statistics unit 1, a video head end 2, and a user access terminal 3, wherein the audience rating unit 1 is configured to analyze the audience rating information of two or more channels to generate an analysis result; The frame interval value of the frame to be inserted in the video stream is adjusted according to the analysis result obtained by the rating unit, and the video stream is encoded according to the frame interval value of the frame to be inserted; The terminal 3 is configured to perform decoding switching according to the video stream that is encoded by the video head end.

The foregoing system may further include a core network. The analyzing unit may include: a dividing module, configured to divide a channel whose viewing rate is greater than the first threshold into a frequently switched channel, and divide the channel whose viewing rate is less than the second threshold into infrequent switching. a channel, the channel whose audience rating is greater than or equal to the second threshold is less than or equal to the first threshold is divided into a stable switching channel; the first sending module is configured to send the divided result; the adjusting unit may include an adjusting module, where the video stream is When the video stream of the channel is frequently switched, the first predetermined value SP frame is inserted, and when the video stream is a video stream of the stable switching channel, the second predetermined value SP frame is inserted, and when the video stream is a video of the infrequent switching channel When the stream is set, the third predetermined value SP frame is inserted. The encoding module may include: an encoding submodule, configured to insert a third predetermined value SP frame for the infrequent switching of the channel, and encode the auxiliary frame in the video stream as a second sending module, configured to send the encoded video stream to the IP multicast mode to Decode the switching unit.

In addition, the above SP frame can provide seamless switching points like I frames, thereby achieving seamless connection between code streams, but in the case of providing the same function, the encoding efficiency of the SP frame is higher than the encoding efficiency of the I frame, and Because of this feature, the SP frame can replace the I frame, which is widely used in inter-stream switching, and greatly reduces the bit rate overhead. Meanwhile, when the switching between different code streams is to be realized, the use of the SI frame is also very effective. At present, when the normal code stream is transmitted, the reference image has a waiting time of 500 ms, and the reference image waiting time taken by the media stream switching system of the present invention is 333 ms, which can save about 200 ms, and the MBMS architecture has unlimited network access and transmission. After a few hundred milliseconds, the terminal's cache is usually small, and its cache time It can be ignored, and the decoding time is also tens to hundreds of milliseconds. In the above part of the time, the total time of channel switching can be controlled within Is, which can effectively improve the user experience.

In addition, the above system can be used in both a wireless network environment and a wired network environment, except that the location of the rating unit is different. In the wireless network environment, the MBMS wireless network architecture is typical, and the unit is located at the radio network controller RNC. In the wired network environment, ADSL wired access is typical, and the unit is set in the Internet Protocol (IP). The GSM evolution technology (edge) node that increases the data rate, the statistical module in the wired network environment is the access node (Access Node, AN) using the digital subscriber line (DSL) access system in the layer 2 control (Layer The 2 control, L2C) protocol reports the multicast membership to the IP edge node, and then the IP edge node counts the ratings.

Further, the video headend and the rating unit may be integrated. In the media stream switching system, the rating information of each channel is sent to the video head end in real time through the statistical unit, and the analyzing unit of the video head end receives the above-mentioned rating information and analyzes it, and at the same time, frequently switches through the coding unit. The channel inserts more SP frames, and encodes the secondary frames in the video stream into SI frames. After receiving the video stream sent by the video headend, the decoding switching unit of the terminal decodes and switches the video stream to achieve normal switching of the video stream. , and the reference image waiting time is greatly reduced, thereby greatly reducing the switching delay of the channel.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or can be implemented by means of software plus necessary general hardware platform, and the technical solution of the present invention. It can be embodied in the form of a software product that can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for making a computer device (may It is a personal computer, a server, or a network device, etc.) that performs the methods described in various embodiments of the present invention. In conclusion, the above description is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

A media stream encoding method, comprising:

And analyzing the audience information of the at least two channels to generate an analysis result; adjusting a frame interval value of the frame to be inserted in the video stream according to the analysis result; and encoding the video stream according to the frame interval value of the to-be-inserted frame In order to perform decoding switching on the video stream.

The media stream encoding method according to claim 1, wherein the analyzing the audience rating information of the at least two channels, before generating the analysis result, further comprising: acquiring the audience rating information of the channel, The obtaining manner includes collecting the rating information of the channel reported by the user terminal, obtaining the rating information of the channel, or acquiring the rating information of the channel from another device.

The media stream encoding method according to claim 1 or 2, wherein the analyzing the audience rating information of the at least two channels, and generating the analysis result comprises: dividing the channel with the audience rating greater than the first threshold into Switch channels frequently;

Dividing a channel whose audience rating is less than the second threshold into infrequently switching channels; dividing a channel whose audience rating is greater than or equal to the second threshold and less than or equal to the first threshold into a stable switching channel, and generating and transmitting the divided result;

The first threshold is greater than the second threshold.

The media stream coding method according to claim 3, wherein the adjusting the frame interval value of the frame to be inserted in the video stream according to the analysis result includes:

Inserting a first predetermined value of the handover prediction frame when the video stream is a video stream that frequently switches channels; Inserting a second predetermined value of the handover prediction frame when the video stream is a video stream of the stable switching channel;

Inserting a third predetermined value of the handover prediction frame when the video stream is a video stream that infrequently switches channels;

Wherein the first predetermined value is greater than the second predetermined value, and the second predetermined value is greater than the third predetermined value.

The media stream encoding method according to claim 4, wherein the encoding the video stream according to a frame interval value of the frame to be inserted comprises:

For infrequently switching channels, a third predetermined value of handover prediction frames is inserted, and the secondary frames in the video stream are encoded as handover frames.

6. A media stream encoding apparatus, comprising:

An analyzing unit, configured to analyze the rating information of each channel received, and generate an analysis result;

And a processing unit, configured to encode the video stream according to a frame interval value of the to-be-inserted frame.

The media stream encoding apparatus according to claim 6, further comprising: a statistical unit, configured to collect the rating information of the channel reported by the user terminal, obtain the rating information of the channel, or obtain the information from another device. The rating information of the channel.

8. The media stream encoding apparatus according to claim 7, wherein the analyzing unit comprises:

a dividing module, configured to divide a channel with a viewing rate greater than a first threshold into a frequent switching frequency Channels that are less than the second threshold are classified as infrequently switched channels, and channels whose audience ratings are greater than or equal to the second threshold and less than or equal to the first threshold are divided into stable switching channels; the first threshold is greater than the second threshold ;

The adjusting unit includes an adjusting module, configured to insert a first predetermined value of a handover prediction frame when the video stream is a video stream that frequently switches channels, and insert a second predetermined value when the video stream is a video stream of the stable switching channel Switching the prediction frame; inserting a third predetermined value of the handover prediction frame when the video stream is a video stream that infrequently switches channels;

9. The media stream encoding apparatus according to claim 8, wherein the processing unit comprises:

And an encoding module, configured to insert a third predetermined value handover prediction frame for infrequently switching channels, and encode the secondary frame in the video stream as a handover frame.

A media stream switching system, comprising: a video head end, a rating statistics unit, and a user access end,

The video head end is configured to adjust a frame interval value of a frame to be inserted in the video stream according to the analysis result obtained by the audience rating unit, and encode the video stream according to the frame interval value of the frame to be inserted. ;

The user access end is configured to perform decoding switching according to the video stream that is encoded by the video head end.

11. The media stream switching system according to claim 10, wherein The video headend and the rating statistics unit are integrated.