Screen video codec method and codec based on progressive text block compression

Abstract

The invention discloses a screen video encoding and decoding method based on progressive character block compression and an encoding and decoding device thereof. The screen video encoding and decoding method comprises the following steps: obtaining a frame in a screen video, and dividing the frame into M*N macro blocks; dividing each macro block into character blocks or image blocks according to the category; dividing each character block into a plurality of character compression code streams according to a main color and a non-main color; encoding the main color by an index table, and progressively encoding escape colors of the non-main color based on a bit plane; dividing each image block into a plurality of image encoding quality layers by using a progressive image encoding algorithm based on wavelet transform; transmitting the code streams to a receiving terminal according to different quality grades; and decoding and displaying the code stream of each quality layer by the receiving terminal. According to the screen video encoding and decoding method disclosed by the invention, in view of the limitation and defects of traditional character encoders, the progressive character encoding technology of a plurality of quality layers is realized, no support of special equipment is needed, and the screen video encoding and decoding method is applicable to all occasions needing to compress screen images containing characters.

Description

【Technical Field】 [0001] The present invention relates to the technical field of data compression, in particular to a screen video coding and decoding method based on progressive text block compression and its codec, which can be used for the compression and transmission of screen video of a computer or a mobile terminal. 【Background technique】 [0002] With the development of multimedia technology and network technology, people have put forward higher requirements on the quality, size and application of computer or mobile terminal screen images. They hope to use limited bandwidth resources to transmit large images and obtain different resolutions according to actual needs. Rate or quality of reconstructed images. This requires the encoder to transmit the outline of the image first, and then gradually transmit the data to continuously improve the image quality to meet the needs of users, and finally achieve lossless compression, that is, the encoder needs to have progressive char...

AI Technical Summary

Problems solved by technology

[0004] 1) The text encoder has only one quality layer, which cannot meet the needs of different applications

[0005] 2) When the network environment is poor, the loss of the text encoding code stream of only one quality layer leads to the loss of the entire text block

[0006] 3) The text encoding of a quality layer often adopts a lossy quantization method, which cannot be displayed losslessly on the receiving end

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