WO2016091000A1

WO2016091000A1 - Dynamic code rate switching method, server and system

Info

Publication number: WO2016091000A1
Application number: PCT/CN2015/091470
Authority: WO
Inventors: 江中央; 王甜甜
Original assignee: 深圳Tcl数字技术有限公司
Priority date: 2014-12-08
Filing date: 2015-10-08
Publication date: 2016-06-16
Also published as: CN105744299A

Abstract

Disclosed is a dynamic code rate switching method, comprising the following steps: a server acquires a downloading code rate of a current video fragment of a program in a server selected to download by a video playing terminal; according to the downloading code rate, dynamically adjusting the code rate of the next video fragment in the server required to download by the video playing terminal; and splicing the beginning of the next video fragment required to download by the video playing terminal and the tail of the current video fragment at the server, and generating a spliced video file for the video playing terminal to download progressively and play. Also disclosed are a server and system for dynamic code rate switching. The present invention can dynamically switch the code rate without requiring the video playing terminal and the server supporting the same dynamic code rate switching technique, thus greatly improving the compatibility between the server and various video playing terminals.

Description

Dynamic bit rate switching method, server and system

Technical field

The present invention relates to the field of video playback technologies, and in particular, to a dynamic rate switching method, a server, and a system.

Background technique

With the development of the Internet and multimedia technologies, it has become a very popular entertainment method to obtain video content from the Internet through video playback terminals such as smart TVs, mobile phones, and PCs. However, since the video is transmitted from the Internet not through the private network but through the public network, the network transmission rate cannot be guaranteed. When network jitter occurs due to network jitter and network delay fluctuations, users may need to constantly buffer the video through the video playback terminal, which causes the video screen to appear stuck, which greatly affects the video. User's viewing experience.

At present, in order to solve the problem of network bandwidth fluctuation caused by network video picture, it is generally through HLS, smooth Streaming, mpeg-dash, HDS and other mainstream adaptive dynamic rate switching technology to solve, the solution is as follows: the server is the same network video program, providing a variety of bit rate video files, during the video playback process, The video playback terminal dynamically switches the code rate of the played video according to the real-time network bandwidth change of the user: when the user network bandwidth becomes larger, the video playback terminal selects a high-rate video fragment file on the server for playing; When the user's network bandwidth becomes small, the video playback terminal selects a low-rate video fragment file on the server to play, so as to avoid the occurrence of the jamming phenomenon caused by the data of the video playback terminal being exhausted. However, the following problems exist in the above solutions:

1. The current mainstream rate adaptive switching technology not only requires the server to provide video fragment files of multiple code rates of the same program, but also needs a video playing terminal in the process of solving the fluctuation of the network bandwidth and causing the network video picture to be stuck. In cooperation, adaptive dynamic rate switching can be implemented according to changes in the user's network bandwidth. For example, there are 3 different bitrates (250kbit/s) on the server. 500kbit/s, 1Mbit/s) file and mpd (media presentation Description) file. Each different rate file consists of multiple shards, one every 10s, At the same time, there is a description file mpd for the multimedia video program on the server, and the mpd file is used to describe the bit rate information and the playing time information of different fragment files. After the program is started, the video playback terminal first downloads the mpd file, and learns from the mpd file how many video segment files of different code rates are present in the current program, and the bit rate, segment playback length and points of each video segment file. The information such as the download address and the video playback terminal respectively download corresponding video segments of different code rates according to the current download speed and the download progress. If the playback is just started, select the slice download with the minimum code rate of 0-10s clock (250kbit/s). When the slice is downloaded, Calculate the network download rate if the download rate is greater than (500kbit/s) , select the 500kbit/s slice download in 11-20s. It can be seen from the above process of rate switching that the video playing terminal needs to cooperate with the server in the whole transmission process according to its own network condition, and supports the same adaptive dynamic rate switching technology.

2. At present, for video playback terminals, few players of video playback terminals can simultaneously support multiple mainstream adaptive dynamic rate switching technologies. That is, not all video broadcast terminals such as smart TVs and mobile phones support HLS and smooth. Adaptive dynamic rate switching technology such as streaming, mpeg-dash, HDS, etc., and when the video playback terminal and the server support the adaptive dynamic rate switching technology are inconsistent, the video playing terminal cannot play the video program provided on the server. It can be seen from the above that the current adaptive dynamic rate switching technology cannot solve the compatibility problem between the server and various video playing terminals well, and the video playing terminal cannot support the adaptive dynamic rate switching technology supported by the server. It may cause the video program to be unable to play or the code rate adaptive switching cannot be achieved, which may affect the video playback.

The above content is only used to assist in understanding the technical solutions of the present invention, and does not constitute an admission that the above is prior art.

Summary of the invention

The main object of the present invention is to provide a dynamic rate switching method, server and system to solve the technical problem that the server cannot be compatible with various video playing terminals.

To achieve the above objective, the present invention provides a dynamic rate switching method, and the method includes the following steps:

The server obtains a download code rate of the current video segment in which the video playback terminal selects to download the program in the server;

Dynamically adjusting a code rate of the next video segment in the server to be downloaded by the video playing terminal according to the download code rate;

The slice header of the next video slice to be downloaded by the video play terminal and the slice end of the current video slice are spliced on the server end to generate a spliced video file for the video play terminal to progressively download and play the spliced video file.

Preferably, the step of obtaining, by the server, a download rate of the current video segment of the video playback terminal that selects to download the program in the server includes:

If the current video fragment is the initial fragment of the program selected by the video playing terminal in the server, the server obtains the initial fragment with the smallest code rate in the selected program for downloading by the video playing terminal, and obtains the code of the video playing terminal. The download rate of the initial fragment with the lowest rate.

The server obtains the download code rate of the current video segment according to the size of the current video segment in which the video playback terminal selects to download the program in the server and the time when the current video segment is downloaded.

Preferably, the step of dynamically adjusting the code rate of the next video segment in the video playback terminal to be downloaded according to the download code rate includes:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.

In addition, in order to achieve the above object, the present invention further provides a server that dynamically switches a code rate, and the server includes:

An obtaining module, configured to obtain a downloading code rate of a current video segment in which the video playing terminal selects to download the program in the server;

An adjustment module, configured to dynamically adjust, according to the download code rate, a code rate of a next video segment of the video playback terminal to be downloaded in the server;

The splicing module is configured to splicing the slice header of the next video slice to be downloaded by the video play terminal and the slice end of the current video slice to generate a spliced video file for the video play terminal to progressively download and play the spliced video file.

Preferably, the obtaining module is further configured to:

If the current video fragment is an initial fragment of the program selected by the video playing terminal in the server, the initial fragment with the smallest code rate in the selected program is obtained for downloading by the video playing terminal, and the code rate of the video playing terminal is obtained. The download rate of the smallest initial shard.

Preferably, the obtaining module is further configured to:

The download code rate of the current video slice is obtained according to the size of the current video slice selected by the video play terminal in the server to download the program and the time when the current video slice is downloaded.

Preferably, the adjustment module is further configured to:

The present invention further provides a system for dynamically switching code rates, the system comprising: a server and a video playing terminal, wherein

The server is configured to obtain a download rate of a current video segment of the video playback terminal that selects to download the program in the server; and dynamically adjust, according to the download code rate, a code rate of the next video segment in the server to be downloaded; Splicing the slice header of the next video slice to be downloaded by the video play terminal and the slice end of the current video slice to generate a spliced video file;

The video playing terminal is configured to send a download request to the server, establish a download connection with the server, and perform progressive download and play on the spliced video file generated by the server.

Preferably, the video playing terminal is further configured to:

The downloaded spliced video file is decoded and played.

The dynamic rate switching method, server and system according to the present invention, according to the download rate of the current video segment of the server selected to download the program by the video playing terminal, the server dynamically adjusts the video playing terminal to download the next video segment. The code rate is spliced at the server end with the slice header of the next video segment to be downloaded by the video playback terminal and the end of the current video segment, thereby realizing the dynamic switching of the video playback terminal to download different video segmentation code rates, and the entire handover The process is completed by the server, and the video playing terminal only needs to gradually download and play the file after the server is spliced, so that the same dynamic bit rate switching technology can be realized without the video playing terminal and the server supporting the same. Dynamic bit rate switching greatly improves the compatibility between the server and various video playback terminals, and can make the download and playback of the player side smoother.

DRAWINGS

1 is a schematic flow chart of an embodiment of a dynamic bit rate switching method according to the present invention;

2 is a schematic diagram of functional modules of an embodiment of a server for dynamically switching code rates according to the present invention;

FIG. 3 is a schematic structural diagram of an embodiment of a system for dynamically switching code rates according to the present invention.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It should be noted that, in the embodiment of the present invention, the video playing terminal may be a terminal having a video playing capability, such as a smart TV, a mobile phone, a PC, etc., and is not limited herein.

The invention provides a dynamic rate switching method.

Referring to FIG. 1, FIG. 1 is a schematic flowchart diagram of an embodiment of a dynamic bit rate switching method according to an embodiment of the present invention.

In an embodiment, the dynamic rate switching method includes:

Step S10: The server acquires a download code rate of a current video segment in which the video playback terminal selects to download the program in the server;

In this embodiment, the server stores a plurality of slice files of different code rates of the same program, that is, the same program of each different code rate is composed of a plurality of slice files, and for one program, each The time interval corresponds to a slice file of a bit rate. After the video playing terminal sends a download request to the server, the server can learn from the download request that the video playing terminal selects the downloaded program in the program that the video playing terminal selects, and the server can adjust the different code rate of the program selected by the video playing terminal to download the program. Fragment file for download by video playback terminal. At the same time, the server can obtain the download code rate of the current video segment in which the video play terminal selects to download the program in the server. Specifically, the current video slice selected by the video play terminal to download the program is saved on the server, and the server can know the size thereof. Information, the server records the time when the video playback terminal starts downloading to download and completes the current video segmentation, and calculates the download code of the current video segment according to the size of the current video segment and the time required to download the current video segmentation. Rate, the download rate directly reflects the current network status and download rate of the video player.

Step S20, dynamically adjusting, according to the download code rate, a code rate of a video clip terminal to download a next video slice in the server;

After obtaining the download code rate of the current video segment by the video playing terminal, dynamically adjusting the code rate of the next video segment of the video playback terminal to be downloaded according to the download code rate: according to the download rate of the current video segment The playing terminal needs to download different code rates of the next video segment in the server for selection, and select a next video segment that is smaller than the download rate and the code rate closest to the download rate as the video playing terminal needs to be downloaded. Next video fragmentation. Since the time interval between adjacent upper and lower two slice files in a program is very short, the video play terminal can be known according to the download code rate of the current video slice selected by the video playback terminal in the server to download the program. Current network status, and the network status of the video playing terminal generally does not change greatly in a short time interval. Therefore, the program saved on the selection server is smaller than the download code rate and the download code rate. The next fragment file of the closest code rate is used as the next video fragment to be downloaded by the video playing terminal, which can ensure that the video playing terminal downloads the next video fragment smoothly, and can fully utilize the network bandwidth of the video playing terminal. Selecting the next slice file with the highest code rate in the network state of the video play terminal as the next video slice to download, ensuring the clarity of the video downloaded by the video play terminal.

Step S30: splicing the slice header of the next video segment to be downloaded by the video playback terminal and the slice header of the current video segment on the server end to generate a spliced video file for the video playback terminal to progressively download and play the spliced video file. .

After the next video segment of the code rate to be downloaded by the video playing terminal is selected, the slice header of the next video segment to be downloaded by the video playing terminal and the ending of the current video segment are spliced on the server end, thereby implementing the video playing terminal. Dynamic switching of downloading different video segmentation rate. The video playback terminal selects the upper and lower video segments of the adjacent time interval in the downloaded program to be spliced to generate a spliced video file, and the video playback terminal can perform progressive download and play according to the generated spliced video file, which can be played. Download and play videos more smoothly.

In this embodiment, according to the download rate of the current video segment selected by the video playback terminal for downloading the program in the server, the server dynamically adjusts the code rate of the video playback terminal to download the next video segment; and downloads the video playback terminal. The slice header of a video segment is spliced with the end of the current video segment, thereby implementing dynamic switching of the video playback terminal to download different video segmentation code rates, and the entire switching process is completed by the server without the participation of the video playback terminal, and the video playback terminal Simply download and play the files that are spliced by the server, so that the dynamic bit rate switching can be realized without the video player and the server supporting the same dynamic bit rate switching technology, which greatly improves the server and various video playback. Compatibility between terminals.

In other embodiments, the foregoing step S10 may further include:

If the video playing terminal starts to start downloading in the server, the current video fragment is the initial fragment selected by the video playing terminal to download the program, because the server cannot know the video playing terminal according to the download rate of the previous video fragment. The network status, the server directly selects the initial fragment with the smallest code rate in the program for the video playback terminal to start downloading. In this way, when the network state of the video playing terminal is unknown, the smoothness of the video segment file in the download server of the video playing terminal can be ensured to the maximum extent, and after the initial segment downloading is completed, the dynamic downloading rate according to the initial segmentation is dynamically performed. Adjusting the video playback terminal needs to download the bit rate of the next video segment in the server, which is more flexible and convenient.

The present invention further provides a server that dynamically switches code rates.

Referring to FIG. 2, FIG. 2 is a schematic diagram of functional modules of an embodiment of a server for dynamically switching code rates according to the present invention.

In an embodiment, the dynamically switching code rate server comprises:

The obtaining module 01 is configured to obtain a download code rate of a current video segment in which the video playback terminal selects to download the program in the server;

In this embodiment, the server stores a plurality of slice files of different code rates of the same program, that is, the same program of each different code rate is composed of a plurality of slice files, and for one program, each time The interval corresponds to a slice file of a bit rate. After the video playing terminal sends a download request to the server, the server can learn from the download request that the video playing terminal selects the downloaded program in the program that the video playing terminal selects, and the server can adjust the different code rate of the program selected by the video playing terminal to download the program. Fragment file for download by video playback terminal. At the same time, the server can obtain the download code rate of the current video segment in which the video play terminal selects to download the program in the server. Specifically, the current video slice selected by the video play terminal to download the program is saved on the server, and the server can know the size thereof. Information, the server records the time when the video playback terminal starts downloading to download and completes the current video segmentation, and calculates the download code of the current video segment according to the size of the current video segment and the time required to download the current video segmentation. Rate, the download rate directly reflects the current network status and download rate of the video player.

The adjusting module 02 is configured to dynamically adjust, according to the download code rate, a code rate of a next video slice in the server to be downloaded by the video playing terminal;

The splicing module 03 is configured to splicing the slice header of the next video segment to be downloaded by the video playback terminal and the end of the current video segment to generate a spliced video file for the video playback terminal to progressively download and play the spliced video file. .

After the next video segment of the code rate to be downloaded by the video playing terminal is selected, the slice header of the next video segment to be downloaded by the video playing terminal is spliced with the ending of the current video segment, thereby implementing different downloading of the video playing terminal. Dynamic switching of video slice rate. The video playback terminal selects the upper and lower video segments of the adjacent time interval in the downloaded program to be spliced to generate a spliced video file, and the video playback terminal can perform progressive download and play according to the generated spliced video file, which can be played. Download and play videos more smoothly.

In other embodiments, the obtaining module 01 may be further configured to:

The present invention further provides a system for dynamically switching code rates.

Referring to FIG. 3, FIG. 3 is a schematic structural diagram of a system for dynamically switching code rates according to an embodiment of the present invention.

In an embodiment, the system for dynamically switching code rates includes: a server 1 and a video playing terminal 2, wherein

The server 1 is configured to obtain a download code rate of the current video slice that the video play terminal 2 selects to download the program in the server 1; dynamically adjust the video play terminal 2 to download the next video slice in the server 1 according to the download code rate. a code rate; splicing the slice header of the next video slice to be downloaded by the video playback terminal 2 and the end of the current video slice to generate a spliced video file;

The video playing terminal 2 is configured to send a download request to the server 1, establish a download connection with the server 1, and progressively download and play the stitched video file generated by the server 1.

In this embodiment, first, the video playing terminal 2 sends a download request to the server 1, and after receiving the download request, the video playing terminal 2 establishes a download connection with the server 1, and starts to download the program that is selected for downloading in the server 1 in sequence. The video segmentation file, in the downloading process, the server 1 dynamically switches the code rate of the video playback terminal 2 to download different video segments according to the network state of the video playback terminal 2, and the next video to be downloaded by the video playback terminal 2 The slice header is spliced with the end of the current video segment to generate a spliced video file, and the process of the dynamic bit rate switching by the server 1 is as described above, and details are not described herein again.

After the spliced video file is generated on the server 1, the video playing terminal 2 progressively downloads and plays the generated spliced video file, wherein progressive downloading (Progressive) Download) is a simple way to download files from server 1. Most media players and platforms support progressive downloads, such as ADOBE. FALSH, SILVERLIGHT and Windows Media Player. Progressive downloads allow video files to start playing when they are still being downloaded, without waiting for the entire file download to finish writing to disk. Therefore, in the embodiment, the server 1 sequentially splices the upper and lower video segments of the adjacent time interval in the program selected by the video playing terminal 2 to generate a spliced video file, and the video playing terminal 2 can The generated spliced video file is downloaded, and the downloaded spliced video file can also be decoded and played. Since most media players and platforms support progressive downloading, most video playing terminals 2 can progressively download and play the stitched video files generated by the server 1, without the video playing terminal 2 supporting the same as the server 1. The dynamic bit rate switching technology improves the compatibility of the video playing terminal 2.

In this embodiment, according to the download rate of the current video segment of the server 1 for downloading the program, the server 1 dynamically adjusts the code rate of the video playback terminal 2 to download the next video segment; and the video playback terminal 2 The slice header of the next video segment to be downloaded is spliced with the end of the current video segment, thereby realizing the dynamic switching of the video playback terminal 2 to download different video segmentation code rates, and the entire switching process is completed by the server 1, without video playback. The terminal 2 participates, and the video playing terminal 2 only needs to progressively download and play the file spliced by the server 1, so that the dynamic bit rate switching can be realized without the video playing terminal 2 and the server 1 supporting the same dynamic bit rate switching technology. The compatibility between the server 1 and various video playing terminals 2 is greatly improved.

The serial numbers of the embodiments of the present invention are merely for the description, and do not represent the advantages and disadvantages of the embodiments. Through the description of the above embodiments, those skilled in the art can clearly understand that the foregoing embodiment method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be through hardware, but in many cases, the former is better. Implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal device (which may be a cell phone, a computer, a server, or a network device, etc.) to perform the methods described in various embodiments of the present invention.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the present invention and the drawings are directly or indirectly applied to other related technical fields. The same is included in the scope of patent protection of the present invention.

Claims

A dynamic rate switching method, characterized in that the method comprises the following steps:

The server obtains a download code rate of the current video segment in which the video playback terminal selects to download the program in the server;

Dynamically adjusting a code rate of the next video segment in the server to be downloaded by the video playing terminal according to the download code rate;

The slice header of the next video slice to be downloaded by the video play terminal and the slice end of the current video slice are spliced on the server end to generate a spliced video file for the video play terminal to progressively download and play the spliced video file.
The dynamic rate switching method according to claim 1, wherein the step of obtaining, by the server, the download rate of the current video segment of the video playback terminal that selects to download the program in the server comprises:

If the current video fragment is the initial fragment of the program selected by the video playing terminal in the server, the server obtains the initial fragment with the smallest code rate in the selected program for downloading by the video playing terminal, and obtains the code of the video playing terminal. The download rate of the initial fragment with the lowest rate.
The dynamic rate switching method according to claim 1, wherein the step of obtaining, by the server, the download rate of the current video segment of the video playback terminal that selects to download the program in the server comprises:

The server obtains the download code rate of the current video segment according to the size of the current video segment in which the video playback terminal selects to download the program in the server and the time when the current video segment is downloaded.
The dynamic rate switching method according to claim 1, wherein the step of dynamically adjusting the code rate of the next video slice in the server to be downloaded by the video playing terminal according to the download code rate comprises:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The dynamic rate switching method according to claim 2, wherein the step of dynamically adjusting the code rate of the next video slice in the server to be downloaded by the video playing terminal according to the download code rate comprises:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The dynamic rate switching method according to claim 3, wherein the step of dynamically adjusting the code rate of the next video slice in the server to be downloaded by the video playing terminal according to the download code rate comprises:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
A server for dynamically switching code rates, wherein the server comprises:

An obtaining module, configured to obtain a downloading code rate of a current video segment in which the video playing terminal selects to download the program in the server;

An adjustment module, configured to dynamically adjust, according to the download code rate, a code rate of a next video segment of the video playback terminal to be downloaded in the server;

The splicing module is configured to splicing the slice header of the next video slice to be downloaded by the video play terminal and the slice end of the current video slice to generate a spliced video file for the video play terminal to progressively download and play the spliced video file.
The server according to claim 7, wherein the obtaining module is further configured to:

If the current video fragment is an initial fragment of the program selected by the video playing terminal in the server, the initial fragment with the smallest code rate in the selected program is obtained for downloading by the video playing terminal, and the code rate of the video playing terminal is obtained. The download rate of the smallest initial shard.
The server according to claim 7, wherein the obtaining module is further configured to:

The download code rate of the current video slice is obtained according to the size of the current video slice selected by the video play terminal in the server to download the program and the time when the current video slice is downloaded.
The server according to claim 7, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The server according to claim 8, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The server according to claim 9, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
A system for dynamically switching a code rate, the system comprising: a server and a video playing terminal, wherein

The server includes:

An obtaining module, configured to obtain a downloading code rate of a current video segment in which the video playing terminal selects to download the program in the server;

An adjustment module, configured to dynamically adjust, according to the download code rate, a code rate of a next video segment of the video playback terminal to be downloaded in the server;

The splicing module is configured to splicing the slice header of the next video segment to be downloaded by the video playing terminal and the end of the current video segment to generate a spliced video file for the video playing terminal to progressively download and play the spliced video file;

The video playing terminal is configured to send a download request to the server, establish a download connection with the server, and perform progressive download and play on the spliced video file generated by the server.
The system for dynamically switching code rates according to claim 13, wherein the video playing terminal is further configured to:

The downloaded spliced video file is decoded and played.
The system for dynamically switching code rates according to claim 13, wherein the obtaining module is further configured to:

If the current video fragment is an initial fragment of the program selected by the video playing terminal in the server, the initial fragment with the smallest code rate in the selected program is obtained for downloading by the video playing terminal, and the code rate of the video playing terminal is obtained. The download rate of the smallest initial shard.
The system for dynamically switching code rates according to claim 13, wherein the obtaining module is further configured to:

The download code rate of the current video slice is obtained according to the size of the current video slice selected by the video play terminal in the server to download the program and the time when the current video slice is downloaded.
The system for dynamically switching code rates according to claim 13, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The system for dynamically switching code rates according to claim 14, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The system for dynamically switching code rates according to claim 15, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.
The system for dynamically switching code rates according to claim 16, wherein the adjustment module is further configured to:

Selecting, according to a download rate of the current video segment, a different code rate of the next video segment of the video playback terminal to be downloaded, selecting a code rate that is smaller than the download code rate and closest to the download code rate. A video slice is used as the next video slice to be downloaded by the video playback terminal.