Research Of Block Based Video Compression Algorithm And Implementation By C

In recent years, video resolution requirement of customer becomes higher and higher. High definition (1920x1080) has become the popular resolution in the past five years. Recently, ultra-high definition (3840x2160) began to be used in cosumer product. In this evolution process, the data to be processed and stored by video decoder in multimedia chip presents the several times of growth, resulting in the huge storage space and bandwidth requirements. All of this become important challenge for the developers of chip.In order to reduce the requirement of storage space and system bandwidth, based on the analysis of the basic process of general video decoding system, this paper propose a solution that compress the image before store it into memory.In order to ensure the quality of compressed video image, and meet the random access requirement of video decoder, this paper identify some direction of subsequent research, such as fixed compression ratio of lossy compression, separate brightness image and color image compression, take the size of4x4pixels block as the object of compression, etc.Then, this paper research some compression algorithm, and expect to find a algorithm to meet all of these requirement. Firstly, this paper evaluate the most popular compression method:Discrete Cosine Transformation based encoding, and identify the best range of the quantize scale. Then, this paper researched and evaluated the Absolute Moment Block Truncation Coding method. Based on this, this paper propose a2order Absolute Moment Block Truncation Coding method. The experiment result shows that the quality of the pixel blocks with big variation is very poor after Absolute Moment Block Truncation Coding, but very good after the2order Absolute Moment Block Truncation Coding. Then, this paper find some pixel block are not suitable for the2order Absolute Moment Block Truncation Coding. So, this paper proposed a modified bitplane coding method. This method can ensure the quality to be good, even for the blocks that with big variation. Finally, based on research of intra-frame prediction, this paper proposed an intra-block prediction coding method. After the effort to enhance this coding method, most of pixel blocks can got the best quality.Based on the research result above, this paper proposed an integrated block based video compression solution. This solution can get near lossless quality, ensure random access, and save half of memory size.