WO2012174956A1

WO2012174956A1 - Iptv channel switching method and device

Info

Publication number: WO2012174956A1
Application number: PCT/CN2012/075308
Authority: WO
Inventors: 曹亚林; 黎定军
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-22
Filing date: 2012-05-10
Publication date: 2012-12-27
Also published as: CN102231848A

Abstract

Disclosed are an IPTV channel switching method and device, capable of buffering media stream data of each IPTV channel sent by a program source; extracting a PAT and a PMT of each IPTV channel; upon receiving a multicast group joining message from a client, sending to the client the PAT and the PMT corresponding to the multicast group joining message; further sending to the client the buffered media stream data of the IPTV channel corresponding to the multicast group joining message. The sent media stream data is completely the copy of the buffered media stream data, so that the present invention enables a client to perform decoding and playing directly, thereby increasing the IPTV channel switching speed.

Description

Method and device for IPTV channel switching

The present invention relates to the field of communications, and in particular, to a method and apparatus for IPTV channel switching. Background technique

With the popularity of network applications, IPTV applications are widely recognized. However, an important issue that plagues operators and users is the slow switching speed of IPTV channels. Existing IPTV systems cannot be compared to traditional cable televisions in terms of switching speed. Therefore, increasing the speed of IPTV channel switching has become an important concern.

The existing IPTV system uses multicast as the basic transmission technology. The channel switch is sent by the client to leave and join the multicast. In the process of channel switching, the reasons for the slow switching speed are the processing time of multicast leaving and joining, the key information acquisition time on the client, and the network transmission delay. The above key information refers to the content that can be directly decoded and played by the client, including the I-frame (Intra-coded Frame), PAT (Program Associate Table) and PMT (Program Mapping) in the encoding. Table, program map table). When the client starts to receive the media stream data, it needs to obtain the key information to start decoding the media stream data. Due to the coding technology and network bandwidth limitation, the key information has a certain time interval in the encoding, such as I frame interval of 2 seconds, PAT and The PMT interval is 0.5 seconds, so the time to wait for critical information becomes a major factor in slow channel switching.

To solve the above problem, the prior art proposes a method for forwarding IPTV media stream data through a cache. When a client joins a new channel, the client directly sends data to the client from the first I frame in the cache. The above method only focuses on accelerating the switching of the IPTV channel through the cache, and only pays attention to the I frame, and does not pay attention to the PAT and the PMT. However, the client only receives the data of the I frame and cannot directly decode it. Output, must have corresponding PAT and PMT to display. And because the content of the cache has a certain delay relative to the content of the live broadcast, for example, three I frames are buffered for the requested channel in the cache. When the channel is requested, the content sent is 3 I before the current live broadcast. The content of the frame, assuming that the interval of the I frame is 2 seconds, the content received by the client is the content before 6 seconds. Thus, there is a delay between the client and the live media stream data, and such delay increases as the cache increases, and cannot be eliminated. Summary of the invention

The main object of the present invention is to provide a method and apparatus for IPTV channel switching, which improves the IPTV channel switching speed.

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

A method for IPTV channel switching, comprising:

Cache media stream data of each IPTV channel sent by the program source;

Extracting a program related table PAT and a program mapping table PMT of each IPTV channel;

When the multicast group of the client is added, the PAT and the PMT corresponding to the multicast group are sent to the client; and the cached IPTV channel corresponding to the multicast group join message is also sent. Media stream data to the client.

After the media stream data is sent to the client, the method further includes:

When the sent media stream data is consistent with the received media stream data, or the media stream data broadcasted by the IPTV channel starts to be sent to the client from the network device where the cache is located, stopping sending the cached media corresponding to the IPTV channel Stream data.

The speed at which the buffered media stream data is transmitted is greater than the speed at which the media stream data is received. The method for sending the media stream data to the client is: sending the buffered media stream data from a complete I frame received last through the cache.

The sending the media stream data to the client includes:

Monitoring whether the transmitted buffered media stream data is consistent with the received media stream data, and Whether the media stream data broadcasted by the IPTV channel starts to be sent from the network device where the cache is located to the client.

A device for switching an IPTV channel, comprising:

a cache module, configured to cache media stream data of each IPTV channel sent by the program source; an extracting module, configured to extract PAT and PMT of each IPTV channel;

The first sending module is configured to: when receiving the multicast group joining message of the client, send the PAT and the PMT corresponding to the multicast group to the client;

The second sending module is configured to send the buffered media stream data of the IPTV channel corresponding to the multicast group join message to the client.

Among them, it also includes:

The stopping module is configured to stop sending the corresponding IPTV channel when the sent media stream data is consistent with the received media stream data, or the media stream data of the IPTV channel is sent to the client from the network device where the cache is located. Cached media stream data.

The speed at which the buffered media stream data is transmitted is greater than the speed at which the media stream data is received. The second sending module, when sending the media stream data to the client, is configured to: start to send the buffered media stream data from a complete I frame received through the cache. Among them, it also includes:

The monitoring module is configured to monitor whether the sent cached media stream data is consistent with the received media stream data, and whether the media stream data broadcasted by the IPTV channel starts to be sent from the network device where the cache is located to the client.

The method and device for IPTV channel switching proposed by the present invention first cache media stream data of all IPTV channels, extract PAT and PMT of each IPTV channel, and identify I frames in the buffer data. When receiving the request of the client to switch the IPTV channel, the PAT and the PMT are sent first, and then the media stream data is sent from the last I frame finally received in the cache, because the sent media stream data is completely cached media stream data. Copy, the client can decode and play directly, speeding up IPTV The switching speed of the channel. Also, since the transmission starts from the last I frame received in the cache, the effect of the delay relative to the live broadcast is reduced. In the present invention, when the cache data is quickly sent to the client, the live media stream data is monitored to be sent from the network device where the cache is located to the client, and the cache data is stopped after the start, and then the live data stream is completely transmitted from the network device. Forwarding, avoiding the delay caused by sending media stream data from the cache. DRAWINGS

1 is a schematic flowchart of a method for IPTV channel switching according to an embodiment of the present invention; FIG. 2 is a schematic flowchart of another embodiment of an IPTV channel switching method according to the present invention; FIG. 4 is a schematic structural diagram of an apparatus for IPTV channel switching according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, an embodiment of a method for IPTV channel switching according to the present invention includes: S10. Media stream data of each IPTV channel sent by a cached program source;

S11. Extract PAT and PMT of each IPTV channel.

512. When receiving the multicast group join message of the client, send the PAT and PMT corresponding to the multicast group join message to the client.

513. Send the cached media stream data of the IPTV channel corresponding to the multicast group join message to the client.

Receive media data streams of all live IPTV channels, cache media data streams, and identify key information, and separately cache PAT and PMT.

When receiving the multicast group join message from the client for the new IPTV channel, the multicast group joins the 4 艮 text to find the cache data corresponding to the IPTV channel, and sends the PAT and PMT of the corresponding IPTV channel in the cache to the client first. Then, the cached media stream data is sent to the client, and the content sent is completely a copy of the cached content. Because all the key information needed for decoding is sent to The client enables the client to directly decode and play after receiving the key information, which reduces the switching time of the IPTV channel and improves the switching speed of the IPTV channel.

In this embodiment, the media stream data of all IPTV channels is first buffered, and the PAT and PMT of each IPTV channel are extracted. When receiving the request of the client to switch the IPTV channel, the PAT and the PMT are sent first, and then the media stream data is sent from the latest I frame in the cache. Since the sent media stream data is completely a copy of the cached media stream data, the client can Direct decoding and playback speeds up the switching speed of IPTV channels.

In an embodiment, S13 may include: starting to send the media stream data in the buffer from the last I frame received last in the cache; identifying the I frame in the media stream data while separately buffering the PAT and the PMT . When receiving the multicast group join message of the client, the PAT and the PMT are sent first, and then the media stream data is sent to the client from the latest complete I frame; in this embodiment, the first I frame is sent from the cache. Cache data, reducing the delay time, and further improving the switching speed of the IPTV channel.

Referring to FIG. 2, another embodiment of the method for IPTV channel switching according to the present invention is provided. In the above embodiment, after performing S13, the method further includes:

514. Check whether the media stream data sent in the buffer is consistent with the received media stream data, and whether the media stream data broadcasted by the IPTV channel starts to be sent from the network device where the cache is located to the client.

515. When the media stream data sent in the cache is consistent with the received media stream data, or the media stream data broadcasted by the IPTV channel starts to be sent to the client from the network device where the cache is located, stop sending the cached corresponding to the IPTV channel. Media stream data.

In this embodiment, the normal forwarding and the cache forwarding of the IPTV channel multicast occur in the same network device, and the media stream data is sent to the client through the cache, and the normal forwarding situation of the IPTV channel multicast requested by the client is directly detected. (ie, the live broadcast situation), to know when the normal multicast media data is forwarded by the normal channel, and also to monitor the sent cache media stream data. No, it is consistent with the arrival of media stream data received by normal multicast.

It is detected that the multicast starts to forward the media stream data to the client normally, or the buffered media stream data is consistent with the media stream data received by the normal multicast (the rate of the buffer transmission may be faster than the rate of receiving the media stream data normally, for example, The normal multicast rate is 1.2 times, which cannot exceed the limit of the downstream access bandwidth, and cannot exceed the receiving capability of the client. The packet data is stopped and the media stream data of the new IPTV channel is normally forwarded in multicast mode.

In this embodiment, the delay caused by sending media stream data from the cache is avoided, and a cache link in the multicast forwarding process is reduced.

Referring to FIG. 3, an apparatus for IPTV channel switching according to the present invention is provided. The method includes: a buffering module 10, configured to cache media stream data of each IPTV channel sent by a program source; and an extracting module 20, configured to extract PAT of each IPTV channel. PMT;

The first sending module 30 is configured to: when receiving the multicast group join message of the client, send the PAT and the PMT corresponding to the multicast group to the client;

The second sending module 40 is configured to send the buffered media stream data of the IPTV channel corresponding to the multicast group join message to the client.

The cache module 10 receives the media data stream of all the IPTV channels that are broadcasted, buffers the media data stream, and the extraction module 20 identifies the key information therein, and separately caches the PAT and the PMT.

When receiving the multicast group join message from the client for the new IPTV channel, the first sending module 30 searches for the cache data corresponding to the IPTV channel according to the multicast group join message, and sends the PAT and PMT of the corresponding IPTV channel in the cache first. To the client, then the second sending module 40 begins to send the cached media stream data to the client, the content being sent is completely a copy of the cached content. Since all the key information required for decoding is sent to the client, the client can directly decode and play after receiving the key information, which reduces the switching time of the IPTV channel and improves the switching speed of the IPTV channel.

In this embodiment, media stream data of all IPTV channels is first buffered, and each IPTV frequency is extracted. The PAT and PMT of the road. When receiving the request of the client to switch the IPTV channel, the PAT and the PMT are sent first, and then the media stream data is sent from the latest I frame in the cache. Since the sent media stream data is completely a copy of the cached media stream data, the client can Direct decoding and playback speeds up the switching speed of IPTV channels.

In an embodiment, the second sending module 40 is specifically configured to: start to send the media stream data in the buffer from the last I frame finally received in the cache. While the extraction module 20 caches the PAT and the PMT separately, it also identifies the I frame in the media stream data. When receiving the multicast group join message of the client, the first sending module 30 first sends the PAT and the PMT, and then the second sending module 40 sends the media stream data to the client from the latest complete I frame. This embodiment compares The buffer data is sent from the first I frame of the cache, which reduces the delay time and further improves the switching speed of the IPTV channel.

Referring to FIG. 4, another apparatus embodiment of the IPTV channel switching of the present invention is proposed. In the foregoing embodiment, the method further includes:

The monitoring module 50 is configured to monitor whether the media stream data sent in the cache is consistent with the received media stream data, and whether the media stream data broadcasted by the IPTV channel starts to be sent from the network device where the cache is located to the client.

The stopping module 60 is configured to stop sending the corresponding IPTV channel when the media stream data sent in the buffer is consistent with the received media stream data, or the media stream data broadcasted by the IPTV channel starts to be sent to the client from the network device where the cache is located. Cached media stream data.

In this embodiment, the normal forwarding and the cache forwarding of the IPTV channel multicast occur in the same network device. When the second sending module 40 sends the media stream data to the client through the cache, the monitoring module 50 directly detects the client requesting the switching. Normal forwarding of IPTV channel multicast (ie, live broadcast), to know when normal multicast forwards new channel media stream data, and also monitors whether the transmitted cache media stream data and media stream data received by normal multicast are received. Arrived consistently.

The monitoring module 50 detects that the multicast starts to normally forward the media stream data to the client, or caches The transmitted media stream data is consistent with the media stream data received by the normal multicast (the rate of the buffer transmission is faster than the rate of receiving the media stream data normally, for example, 1.2 times the normal multicast rate, and cannot exceed the limit of the downstream access bandwidth. When the client does not exceed the receiving capability, the stop module 60 stops sending cached data.

In summary, the method and device for IPTV channel switching proposed by the present invention first cache media stream data of all IPTV channels, extract PAT and PMT of each IPTV channel, and identify I frames in the buffer data. When receiving the request of the client to switch the IPTV channel, the PAT and the PMT are sent first, and then the media stream data is sent from the last I frame finally received in the cache, because the sent media stream data is completely cached media stream data. Copy, the client can directly decode and play, speeding up the switching speed of the IPTV channel. Also, since the transmission starts from the last I frame received in the cache, the effect of the delay relative to the live broadcast is reduced. In the present invention, when the cache data is quickly sent to the client, the live media stream data is monitored to be sent from the network device where the cache is located to the client, and the cache data is stopped after the start, and then the live data stream is completely transmitted from the network device. Forwarding, avoiding the delay caused by sending media stream data from the cache.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

1. A method for IPTV channel switching, comprising:

Cache media stream data of each IPTV channel sent by the program source;

When receiving the multicast group join message of the client, the PAT and the PMT corresponding to the multicast group join message are sent to the client; and the cached one of the IPTV channel corresponding to the multicast group join message is also sent. Media stream data to the client.

2. The method of claim 1, wherein after transmitting the media stream data to the client, the method further comprises:

3. The method of claim 2, wherein the speed of transmitting the buffered media stream data is greater than the speed of receiving the media stream data.

The method according to any one of claims 1 to 3, wherein the method of transmitting the media stream data to a client is to start transmitting the buffered media stream data from a complete I frame received last through the buffer. .

The method according to any one of claims 1 to 3, wherein, when the media stream data is sent to the client, the method further includes:

The monitored cached media stream data is consistent with the received media stream data, and whether the media stream data broadcasted by the IPTV channel starts to be sent from the network device where the cache is located to the client.

6. A device for switching an IPTV channel, comprising:

a cache module, configured to cache media stream data of each IPTV channel sent by the program source; an extracting module, configured to extract PAT and PMT of each IPTV channel; The first sending module is configured to: when receiving the multicast group joining message of the client, send the PAT and the PMT corresponding to the multicast group joining message to the client;

7. The apparatus according to claim 6, further comprising:

8. The apparatus of claim 7, wherein the speed at which the buffered media stream data is transmitted is greater than the speed at which the media stream data is received.

The device according to any one of claims 6 to 8, wherein the second sending module is configured to: when transmitting the media stream data to the client:

The buffered media stream data is transmitted starting from the last I frame received through the cache.

The device according to any one of claims 6 to 8, further comprising: a monitoring module, configured to monitor whether the sent buffered media stream data is consistent with the received media stream data, and the IPTV channel is broadcasted. Whether the media stream data starts to be sent from the network device where the cache is located to the client.