WO2012094992A1

WO2012094992A1 - Method and system for data acquisition

Info

Publication number: WO2012094992A1
Application number: PCT/CN2012/070198
Authority: WO
Inventors: 赵宇; 王芳; 孙健; 陈翼; 李加周; 阮亚平
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-01-10
Filing date: 2012-01-10
Publication date: 2012-07-19
Also published as: CN102594773A; CN102594773B

Abstract

Disclosed are a method and system for data acquisition, both of which can include, in the segments of a TS code stream, index information for identifying media segment information and can also acquire frames at the RAP to be played in trick mode or during file switching according to the media segment information included in the index information. Data acquisition technology can be realized by means of the method and system in the present invention, wherein during fast forward/fast backward or media stream switching, the client end can quickly locate the start and stop position of the RAP to be played, and only corresponding frames will be downloaded for playback. Moreover, the client end can also switch to play modes such as normal play or time shifting smoothly. Thus data downloaded in trick mode or during file switching can be reduced effectively, and smoothness of play and user satisfaction can be improved significantly.

Description

Method and system for realizing data acquisition

The present invention relates to the field of communications, and in particular, to a method and system for implementing data acquisition. Background technique

With the development of technology, a streaming media service based on the HTTP protocol has emerged, namely the HTTP Streaming service. In recent years, the broadcasting service and the mobile service have gradually merged, and different multimedia contents and services are transmitted on different networks. The MPEG2-TS used for broadcasting is also widely used on the Internet. Similarly, MPEG2-TS is also used in the HTTP Streaming service.

Since the HTTP protocol is essentially a text transfer protocol, it is not suitable for real-time streaming media delivery. In order to facilitate live playback (for time-shifted services) and download-side viewing functions, the program content is usually physically or logically divided into many small segments, as shown in Figure 1. The client downloads one or more segments of the media file each time according to a Media Presentation Description (MPD) containing information such as a media segment, and then decodes the downloaded data. However, for the fast forward and rewind function, the usual method is to download the corresponding segment according to the MPD, and then find the corresponding random access point (RAP) in the segment file to play, so that non-RAP data will also be played. It is downloaded, so the client will download a lot of redundant data, which seriously affects the smoothness of playback and excessively consumes network bandwidth. Summary of the invention

In view of this, the main object of the present invention is to provide a method and system for implementing data acquisition to reduce data downloaded during trick mode or file switching, and to improve the smoothness of playback.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A method for realizing data acquisition, which is used for identifying a segment of a transport stream TS code stream The index information of the media segmentation information, the method further includes: acquiring, according to the media segmentation information included in the index information, a frame at a random access point RAP that needs to be played during a trick mode or file switching.

The method for setting the index information is: adding an index for identifying the media segment information in a segment of each TS code stream;

The index information includes at least the following indications: whether the RAP identifier or the RAP number is included; when there is a RAP, the information includes an offset address for identifying each RAP point, and a identifier for identifying each RAP. length.

The index information further includes at least one of the following:

The total length of the RAP index information;

RAP type, used to identify the type of the corresponding segmentation RAP;

RAP timestamp information, which is used to identify the play time corresponding to each RAP;

The program identification PID of the code stream carrying the RAP.

The process of acquiring the frame at the RAP according to the media segment information included in the index information includes:

Download and parse the media segmentation information included in the index information;

The offset and length of the RAP to be acquired are parsed from the media segmentation information, and the frame at the RAP is requested to be downloaded accordingly.

The trick mode includes at least one of the following:

Fast forward/rewind, fast forward to normal playback, time shift positioning playback, file switching.

A system for implementing data acquisition, comprising an index information maintenance unit and a data acquisition execution unit; wherein

The index information maintenance unit is configured to set index information for identifying media segment information in a segment of the TS code stream, and notify the data acquisition execution unit of the index;

The data acquisition execution unit is configured to: according to the media segmentation information included in the index information Information, the frame at the RAP that needs to be played when the trick mode or file is switched.

The index information maintenance unit is configured to: add an index for identifying the media segment information in a segment of each TS code stream when the index information is set;

The index information further includes at least one of the following:

The total length of the RAP index information;

RAP type, used to identify the type of the corresponding segmentation RAP;

The PID of the code stream carrying the RAP.

The data acquisition and execution unit acquires the frame at the RAP according to the media segmentation information included in the index information, and is used to:

The trick mode includes at least one of the following:

The method and system of the invention realizes the technology of data acquisition, and the client can quickly locate the start and end positions of the RAP to be played during fast forward/rewind and media stream switching, and only download the corresponding frame for playing, and can Smoothly switch to playback mode such as normal play or time shift; thus it can effectively reduce the data downloaded during trick mode or file switching, significantly improve the smoothness of playback, and significantly improve user satisfaction. DRAWINGS

1 is a schematic structural diagram of a prior art MPEG2-TS logical segment; 1 is a schematic structural diagram of an MPEG2-TS logical segment and a RAP index segment according to an embodiment of the present invention;

3 is a schematic diagram of generating a RAP information segment according to an embodiment of the present invention;

4 is a flowchart of implementing fast forwarding according to an embodiment of the present invention;

FIG. 5 is a flowchart of implementing fast forward and normal playback according to an embodiment of the present invention; FIG.

6 is a flowchart of implementing time shift positioning playback according to an embodiment of the present invention;

FIG. 7 is a schematic flowchart of implementing data acquisition according to an embodiment of the present invention;

FIG. 8 is a system diagram of implementing data acquisition according to an embodiment of the present invention. detailed description

In practical applications, for the transport stream (TS) file in the Http Streaming scenario, the client wants to quickly locate the RAP start and end positions that need to be played during fast forward/rewind and media stream switching, and only download the corresponding The frame is played for playback, and can also be smoothly switched to a play mode such as normal play or time shift.

As shown in Fig. 2, an index for identifying the media segmentation information may be added before the segment of each TS code stream. Of course, in practical applications, the index may also be added after the segmentation of each TS code stream. FIG. 3 is a schematic diagram of RAP information segmentation, and the RAP information included in the index is as follows:

The total length of the RAP index information, including this field. This field can be used to discard RAP index data on normal demand. This information is optional.

Whether to include the RAP identifier or the number of RAPs; this information is mandatory.

RAP type: This element identifies the type of the corresponding segmentation RAP; this information is optional. Program Identification (PID): The PID of the code stream carrying the RAP.

Offset address of RAP: Identifies the offset address of each RAP point; this information is optional. This field must exist when there is a RAP; otherwise, the field does not exist.

Length of RAP: Identifies the length of the keyframe at each RAP point; this information is optional. This field must exist when there is a RAP; otherwise, the field does not exist.

RAP timestamp information: identifies the playback time corresponding to each RAP; this information is optional. It should be noted that, in addition to the mandatory content, the RAP information may include at least one of the above contents.

Based on the above index structure, the following methods of fast forward/reverse playback, positioning playback, and switching can be performed.

A, the method of fast forward and rewind

Further, the step A includes:

A1, the client receives the trick command (such as: fast forward / rewind);

A2, determine the next RAP address (such as URL);

The client determines the segment where the next RAP is located according to the current play time and the fast forward/reverse command, and obtains the index information from the segment and forms the address of the frame at the RAP, including the basic unified resource location of the URL and the segment. Base url of segment + byte range, etc.

Determine the interval for downloading the RAP frame according to the fast forward/reverse parameters (such as multiples);

A3, the client downloads the corresponding RAP frame and decodes the display.

B, the method of realizing fast forward and fast retreat to normal play

Further, the step B includes:

B1, the fast forward/rewind multiple is changed to 1 times and then the corresponding fast forward/rewind operation is performed until the downloaded RAP is an instant update access point (IDR);

B2, obtaining an offset and a length of the RAP from the RAP information segment;

B3, the client requests to download all the data of the TS segment after the RAP, and then changes to normal play after downloading.

C. Method for realizing time shift positioning and on demand

Further, the step C includes: CI, finding a corresponding TS segment according to a time shift on-demand time point;

C2, calculating the presentation time of the time-shifting on-demand point. Finding, according to the MPD, the RAP information segmentation URL corresponding to the segment, requesting to download the RAP information segment;

C3, parsing the RAP information segment, and finding a RAP whose PTS is greater than or equal to the on-demand point presentation time and the RAP type is IDR;

C4, the client requests to download all the data of the TS segment after the RAP, and then changes to normal play after downloading.

D. How to implement media stream switching:

Further, the step D includes:

D1: The network bandwidth changes, the client or the system detects the change, and determines to perform media stream switching (for example, switching from a media file having a different resolution and the like to a media file 2);

D2: The client determines the switching location according to the current playing time and the segmentation information (such as the corresponding segmentation of the media file 2, time information, and RAP information);

D3: The client requests the media segment at the switching location (such as the segmentation of media file 2), decodes and displays the data frame, and implements media adaptive switching.

The present invention will be described in detail below with reference to the drawings and specific embodiments.

It should be noted that the embodiment of the present invention adopts MPEG2-TS as the media file storage format on the streaming media server, and performs logical segmentation on it. Add a RAP message for the segment in front of the MPEG2-TS logical segment. In order to quickly find the corresponding RAP during fast forward/rewind, positioning playback, etc., to improve the processing power of the server.

Moreover, in practical applications, it is only necessary to simply discard the RAP information part of the conventional normal on-demand and live broadcast. The first field of the RAP index information is the total length of the RAP index. According to this length, the client can easily discard the RAP index information. When the user performs the trick mode, the exchange process between the server and the client changes. As shown in Figure 4, after using the present invention, Accelerate the search for RAP. The process shown in Figure 4 includes the following steps:

Step 401, fast forward begins.

Step 402: Determine whether the fast forward is over. If it is over, it jumps to step 410; otherwise, it jumps to step 403.

Step 403: Determine the segment where the next RAP is located according to the current playing time and the fast forward multiple. Step 404: Determine whether the RAP index information corresponding to the segment has been downloaded. If yes, go to step 406; otherwise, go to step 405.

Step 405: Find location information of the TS segment in the MPD. Download the first 1024 bytes of the segment. The RAP index information is at the beginning of the TS segment, and since the RAP index information is small, 1024 bytes are large enough, so there is no need to record the offset and size in the MPD for the RAP information.

Step 406: The client parses the downloaded RAP index information (that is, the media segment information included in the index information, the same applies hereinafter).

Step 407: Obtain an offset and a length of the RAP.

Step 408: The client requests the server to download the frame at the RAP.

Step 409, the client processes the frame at the downloaded RAP, and then jumps to step 402. Step 410, ending.

It can be seen that, based on the index information, the media segment information included in the index information can be downloaded and parsed, and the offset and length of the RAP to be acquired are parsed from the media segment information, and the request is requested accordingly. Download the frame at the RAP.

During fast forward to normal playback, the process shown in Figure 5 can be performed, which includes the following steps:

Step 501: Fast forward to normal playback starts.

Step 502: Obtain the last RAP of the fast forward.

Step 503: Determine whether the RAP is an IDR. If yes, jump to 507; otherwise, Go to step 504.

In step 504, the fast forward operation is performed by changing the fast forward multiple to 1 time.

Step 505, fast forward operation.

Step 506, acquire the next RAP, and jump to 503.

Step 507: Obtain an offset and a length of the RAP from the RAP information segment.

Step 508: The client requests to download data of all the TS segments subsequent to the RAP. In step 509, the next segment is switched to the normal playback process.

Step 510, the end.

When performing time shift positioning playback, the flow shown in FIG. 6 can be performed, assuming that the live stream in FIG. 6 has only a video stream, that is, there is only one track in the code stream. The process shown in Figure 6 includes the following steps: Step 601: Obtain the time of the time shift positioning play.

Step 602: Determine whether the acquired time is Coordinated Universal Time (UTC), if yes, go to step 604; otherwise, go to step 603.

Step 603: Convert the time-shifted playback time to the UTC time.

Step 604: Obtain a start UTC of the TS file from the MPD.

Step 605: Calculate the presentation time of the on-demand time point.

Step 606: Traverse the initial presentation time of each segment recorded in the MPD, and calculate the segment where the playback point is located.

Step 607: Obtain the location information of the segment from the MPD, and download the first 1024 bytes. Since the RAP index information is at the beginning of the TS segment, and since the RAP index information is small, 1024 bytes are already large enough, so there is no need to record the offset and size in the MPD for the RAP information.

Step 608, traversing the RAP index information, and then finding a RAP whose RAP type is IDR and the PTS is greater than or equal to the presentation time of the on-demand time point.

Step 609: Construct a URL of all the data of the segment after the RAP according to the offset and size of the RAP and the URL of the TS segment, and request a download from the server. In step 610, the next segment is switched to the normal playback process.

According to the foregoing embodiments, the operation of the present invention for implementing data acquisition may represent a process as shown in FIG. 7, and the process includes the following steps:

Step 710: Set index information for identifying media segmentation information in the segment of the TS code stream. Step 720: Acquire, according to the media segmentation information included in the index information, a frame at the RAP that needs to be played during the trick mode or file switching.

In order to ensure that the above embodiments and operation ideas can be smoothly implemented, the settings shown in FIG. 8 can be performed. Referring to FIG. 8, FIG. 8 is a system diagram for implementing data acquisition according to an embodiment of the present invention, where the system includes a connected index information maintenance unit and a data acquisition execution unit.

In a specific application, the index information maintenance unit can set index information for identifying the media segmentation information in the segment of the TS code stream, and notify the data acquisition execution unit of the index; The media segmentation information included in the index information is used to obtain a frame at the RAP that needs to be played during the trick mode or file switching.

In summary, the present invention realizes the data acquisition technology, and the client can quickly locate the RAP start and end positions that need to be played during fast forward/rewind and media stream switching, and only download. The corresponding frame is played, and can be smoothly switched to a play mode such as normal play or time shift; thus, data downloaded during trick mode or file switching can be effectively reduced, the smoothness of playback is significantly improved, and user satisfaction can be significantly improved.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention. INDUSTRIAL APPLICABILITY The present invention provides a method and system for implementing data acquisition, which may include index information for identifying media segmentation information in a segment of a TS code stream, and may also include media included in the index information. Segmentation information, the frame at the RAP that needs to be played when the trick mode or file is switched. The method and system of the invention realizes the technology of data acquisition, and the client can quickly locate the start and end positions of the RAP to be played during fast forward/rewind and media stream switching, and only download the corresponding frame for playing, and can Smoothly switch to playback mode such as normal play or time shift; thus it can effectively reduce the data downloaded during trick mode or file switching, significantly improve the smoothness of playback, and significantly improve user satisfaction.

Claims

Claim

A method for implementing data acquisition, where the segment of the transport stream TS code stream includes index information for identifying media segmentation information, the method further comprising: according to the media segmentation information included in the index information, Gets the frame at random access point RAP that needs to be played during trick mode or file switching.

2. The method according to claim 1, wherein the method for setting the index information is: adding an index for identifying the media segment information in a segment of each TS code stream;

3. The method according to claim 2, wherein the index information further comprises at least one of the following:

The total length of the RAP index information;

RAP type, used to identify the type of the corresponding segmentation RAP;

The program identification PID of the code stream carrying the RAP.

The method according to any one of claims 1 to 3, wherein the process of acquiring the frame at the RAP according to the media segmentation information included in the index information comprises:

5. The method according to claim 1, wherein the trick mode comprises at least the following fast forward/rewind, fast forward normal play, time shift local play, and file switch.

6. A system for implementing data acquisition, including an index information maintenance unit, and a data acquisition execution Unit; among them,

The data acquisition execution unit is configured to obtain, according to the media segmentation information included in the index information, a frame at a RAP that needs to be played during a trick mode or file switching.

The system according to claim 6, wherein, when the index information maintenance unit sets the index information, it is used to: add a segment for identifying the media segmentation information in a segment of each TS code stream. Index

8. The system according to claim 7, wherein the index information further comprises at least one of the following:

The total length of the RAP index information;

RAP type, used to identify the type of the corresponding segmentation RAP;

The PID of the code stream carrying the RAP.

The system according to any one of claims 6 to 8, wherein the data acquisition and execution unit acquires the frame at the RAP according to the media segmentation information included in the index information, and is used for:

10. The system of claim 6, wherein the trick mode comprises at least one of: Fast forward/rewind, fast forward to normal play, time shift positioning playback, file switching