Method for transmitting video-frequency flow in network

Abstract

A method for transmitting video stream in network includes providing a video source section in mode of compressed video stream with at least two different code rates as each video stream being included with at least one video frame coded by interframe coding mode and with at least one frame identified to be type of enabling to be discarded, coding one switch-over frame for each pair video stream, switching network to low code rate video stream when network band width is changed from high to low and switching it to high code rate video stream when network band width is changed from low to high.

Description

technical field [0001] The invention belongs to the field of data communication and relates to the fields of scalable video compression and streaming media transmission. Background technique [0002] A video is composed of a series of continuous still images, which are displayed on the screen at high speed to give people the feeling of moving objects in a movie, and each image is called a frame. Video compression is a collection of algorithms used to compress video so that it satisfies the bit-count (ie, bandwidth) constraints determined by the transmission medium. For example, a communication cable in a local area network can transmit video at a fixed rate of 8Mbps (megabits per second), but the transmission rate will drop significantly in a cellular network. [0003] Multimedia codec usually consists of two parts: encoder and decoder. The encoder compresses the original data to a certain size for transmission. Generally speaking, the larger the compression ratio, the wo...

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Problems solved by technology

[0007] Each of the above methods has its own disadvantages: Scalable video requires the decoder to support multi-layer decoding

The disadvantage of this method is that the use of switching frames leads to a serious degradation of image quality, especially in the case of cellular networks, frequent switching will cause serious degradation of the image quality of the reconstructed video until it is unavailable

In order to solve this problem, Farber and Girod pointed out that a small quantization level can be used to encode switching frames, but this will result in very large switching frames and consume a lot of network resources, which is not advisable on narrowband networks

On the basis of Farber and Girod, Falik, Yohai and others in the US patent " 20030123546 Scalablemulti-level video coding" proposes to introduce the intra-frame coding block mode (encoding some blocks of the inter-frame coding frame in the intra-frame coding mode) into the video stream, so that the quality of the reconstructed video image is better than that of Farber and Farber when the stream is switched. The method proposed by Girod, but this method is less adaptable to network bandwidth changes than that of a video stream that determines a certain frame loss method during video encoding and combines it with the stream switching method to adapt to network bandwidth changes.

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