Method and structure that audio-video-frequency broadcast network direct broadcasting channel switches
Technical field
The present invention relates to realize a kind of in IP broadband environment lower network TV (hereinafter to be referred as IPTV) network direct broadcast band fast switching method and system configuration, more particularly, be a kind of method and system structure based on key-frame extraction technology and set-top box buffer memory control strategy.
Background technology
IP broadband environment lower network television services is to cater to the user to the professional growing demand of home entertaining, the broadband new business that occurs along with the development of technology such as broadband network, encoding and decoding, flow transmission.As one of basic service in this new business, visual broadcast service with traditional broadcast television content high efficient coding after, be transferred to user terminal by IP network.
Channel suitable customer requirements switching time of current cable, be controlled in 1 second, therefore, in the audio-video-frequency broadcast business, if channel is oversize switching time, the user just has tangible wait sense when using business, produces and is sick of, thereby the business of influence is carried out, and therefore improving audio-video-frequency broadcast channel switch speed just seems extremely important.
So-called channel switches and is meant the user when watching programme televised live, adds/subtracts "+/-" key or numerical key from pressing channel and be presented at duration on the video screen to the image of corresponding channel program.At present based on the IPTV of multicasting technology live in, general channel handoff technique is based on that the IGMP agreement finishes.When the channel switching is done in operation, set-top box at first sends IGMP Leave Group request to the direct broadcast server that adopts multicasting technology and leaves current multicast group, cut off current live TV stream, send IGMP Join request to direct broadcast server then and add another multicast group, receive new multicast data flow data and decoding and display image, finish channel and switch.As everyone knows, channel is subjected to the network equipment to a plurality of factor affecting such as multicast packets processing delay, direct broadcast server response time, set-top-box chip processing speeds switching time.As can be seen, each step of the professional mid band handoff technique of existing IPTV is serial operation, and after cutting off current live data streams, before the new live data streams of demonstration, the user must be through the stand-by period of one period " blank screen ".Because existing IPTV live broadcast service based on multicasting technology generally surpasses 2 seconds during this period of time, therefore, the user can produce tangible wait sensation.If run into network congestion again, then the time may be longer.
Summary of the invention
The object of the present invention is to provide a kind of direct broadcast band fast switching method and system configuration of in IP broadband environment lower network TV (hereinafter to be referred as IPTV) network, realizing, make under audio frequency and video live broadcast service environment, realize that in conjunction with key-frame extraction technology and set-top box buffer memory control strategy direct broadcast band switches fast based on multicasting technology.
Technical scheme of the present invention is as follows:
1), the user uses channel selecting key to carry out channel to switch according to a kind of direct broadcast band fast switching method that in the IPTV network, realizes of the present invention, comprises step:; 2), set-top box receives the user channel handoff request by infrared interface; 3), set-top box leaves current multicast group to the direct broadcast server request, after the direct broadcast server response, set-top box is just cut off current live TV stream data; 4), set-top box is to the content-data of the corresponding channel of live processing server request, live processing server response request is carried the key frame data in short-term of corresponding channel to set-top box; 5), set-top box opens up two data buffering areas, receives the key frame data in short-term of corresponding channel, deposits buffering area A in, and play; 6), set-top box adds the new multicast group of corresponding channel to the direct broadcast server request, after the direct broadcast server response, set-top box receives the live TV stream data of corresponding channel; 7), set-top box receives the live TV stream data of corresponding channel, deposits buffering area B in; 8), set-top box switches to the data of play buffer B from the data of play buffer A, realizes the switching of channel;
More specifically, the channel selecting key described in the step 1) comprises and adds/subtract "+/-" key or numerical key or combination of numbers key; Key frame data in short-term described in the step 4) is meant the data flow in corresponding 2 seconds of the extraction of direct broadcast band key frame;
Communication between described set-top box and live processing server and the direct broadcast server is pressed the IGMP agreement and is connect.
Technical conceive according to above method, a kind of system configuration that direct broadcast band switches fast that in the IPTV network, realizes of the present invention, comprise direct broadcast server that is arranged on the IPTV network edge and the set-top box that connects with the simulated television assembly, this direct broadcast server becomes live connection through bearer network equipment connection programme televised live source and with set-top box, characteristics are: also at the IPTV network edge live processing server is set, it receives and the video requency frame data in short-term of all direct broadcast bands that the buffer memory direct broadcast server is exported flows, and carries out key frame and deposit buffering area A and temporary storage buffer region B; This live processing server and set-top box connect with the communication of IGMP agreement.
More specifically, the video data stream in short-term of said direct broadcast band is meant the video data stream in the 2 second time that key frame extracted of direct broadcast band.Said key frame is meant can represent the frame of video of video frequency band main contents in short-term.
Advantage of the present invention is: utilize the present invention to carry out direct broadcast band and switch, can make present direct broadcast band switching time from dropping to 1 second greater than 2 seconds, improve IPTV user's television experience greatly.Though, use technical scheme of the present invention, need set up live processing server, to network design, system configuration can not produce essence and change, and realizes simple.
Description of drawings
Fig. 1 is that the present invention realizes the system architecture diagram that direct broadcast band switches fast in the IPTV network;
Fig. 2 is that the present invention realizes the flow chart that direct broadcast band switches fast in the IPTV network.
Embodiment
Provide better embodiment of the present invention according to Fig. 1 and Fig. 2 below, and described in detail, enable technical characterictic of the present invention and function characteristics are described better, rather than be used for limiting scope of the present invention.
See also Fig. 1, as shown in the figure, the structure that the direct broadcast band of existing IPTV live broadcast service based on multicasting technology switches comprises the direct broadcast server 20 that is arranged on network edge and the set-top box 30 that connects mutually with simulated television, direct broadcast server 20 connects programme televised live source 1 through bearer network equipment 2, channel switches to be finished based on the IGMP agreement, at first send IGMPLeave Group by set-top box 30 to direct broadcast server 20, current multicast group is left in request, cut off current multicast group data stream, send IGMP join to direct broadcast server 20 then, request adds another multicast group, receives new multicast group data stream and decoding and display image, finishes channel and switches.As improvement, in the present invention, set up live processing server 21 at network edge, it receives the live data of direct broadcast server 20, and with all direct broadcast band short time data streams of first-in first-out buffer memory; And on set-top box 30 address and live processing server 21 addresses of pre-configured direct broadcast server 20, and key frame data temporary storage buffer region A and buffering area B in short-term.The user adds corresponding multicast group, and receiving group group flow data is watched programme televised live.
See also Fig. 2, the user controls remote controller and carries out the direct broadcast band switching, and treatment step is as follows:
1), the user adds/subtracts "+/-" key or numerical key by channel, carry out channel and switch;
2), set-top box 30 is by infrared mouthful receiving channels handoff request, channel-identification number;
3), set-top box leaves current multicast group to the direct broadcast server request, the direct broadcast server response, set-top box is cut off current live TV stream data;
4), set-top box is to the content-data of the corresponding channel of live processing server 21 requests, live processing server 21 is response request just, carries the key frame data in short-term of corresponding channel to set-top box 30;
5), set-top box 30 opens up two data buffering area A, B, receives the key frame data in short-term of corresponding channel, deposits buffering area A in, and play;
6), set-top box 30 adds the new multicast group of corresponding channel to direct broadcast server 20 request, direct broadcast server 20 responses, set-top box 30 receives the live TV stream data of corresponding channel;
7), set-top box 30 receives the live TV stream data of corresponding channel, deposits buffering area B in;
8), set-top box 30 switches to the data of play buffer B from the data of play buffer A, realizes the switching of channel.