Audiovideo interaction low-delay transmission method and background server

An audio/video interaction low-delay transmission method, wherein comprising the following steps:

• S1:
• a driving receiving end maintaining long connection communication with a sending end by means of a transmission control protocol (TCP), and the receiving end sending a video frame feature to the sending end, wherein the video frame feature includes video playback frame rate, resolution and code rate, as well as audio sampling rate, sampling digit and number of channels;
• S2:
• sending, by the sending end to the receiving end, a video frame satisfying the video frame feature, and accumulating a number of video frames obtained by the receiving end within a plurality of continuous preset time periods;
• S3:
• determining whether the number of the video frames obtained within a preset number of preset time periods within the plurality of continuous preset time periods satisfies a preset range, if yes, determining that a network condition is normal, and maintaining an original state;
• and if not, determining that the network condition fluctuates, and performing S4;
• S4:
• adjusting a current code rate level of the receiving end, generating a new video frame feature, sending the new video frame feature to the sending end, and performing S2;
• after the receiving end sending the new video frame feature to the sending end, the method further comprises the following steps:
• S5:
• the driving receiving end obtaining the video frames sent by the sending end through user datagram protocol (UDP), and storing the video frames in a buffer area;
• S6:
• obtaining a current number of the video frames and the video playback frame rate in the buffer area, obtaining a first video playback frame rate by a formula:
• y=[tan (S/F−1)+1]*F+F, and conducting accelerated playback of a next video frame based on the first video playback frame rate;
• where y is a first video playback frame rate, S is the current number of the video frames in the buffer area, and F is a current video playback frame rate;
• the step S6 is specifically implemented by the following steps:
• S61:
• determining whether S/F is greater than 2, if yes, emptying the buffer area, and retaining only the video frame obtained by the receiving end at the current time;
• and if not, performing S62;
• S62:
• determining whether S/F is greater than 1−π/4, if not, maintaining an original state;
• if yes, obtaining the current video playback frame rate by a formula:
• y=[tan (S/F−1)+1]*F+F, obtaining the first video playback frame rate and conducting accelerated playback of the next video frame based on the first video playback frame rate;
• where y is the first video playback frame rate, S is current number of the video frames in the buffer area, and F is the current video playback frame rate;
• S63:
• calculating the playback time between the previous frame and the next frame at intervals by a formula:
• t=1/y, where t is the playback time between the previous frame and the next frame at intervals, and y is the first video playback frame rate;
• S64:
• determining whether the number of the video frames in the buffer area is greater than 5, if not, stopping the accelerated playback.