MPEG-2 Video Transcoding Method In DCT Domain Based On Rate Control

In the recently years, due to the advances of network technologies and wide adoptions of video coding standards, networked multimedia services, such as video on demand, video streaming, and distance learning, become increasingly popular in our life. To flexibly deliver multimedia data to the users with different available resources, access networks, and interests, the multimedia content may need to be adapted dynamically according to the usage environment. Transcoding is one of the key technologies to fulfill this challenging task.Tanscoding in the compressed domain has better efficiency compared to that in the pixel domain, due to reusing the information of bit stream and eliminating the need to compute the discrete cosine transform(DCT) and its inverse transform (IDCT). In this paper, the hardware structure of bit-rate transcoding system based on TM5 is proposed, and some key modules just like rate control and Motion compensation in the DCT (MC_DCT) are completed. Among MC_DCT, computational complexity is reduced based on using approximate matrices. Parallel design and systolic array structure is adopted in the overall design in this paper.Through certain kind of combination, the constant elements is converted to binary numbers with a maximum distortion of 1/32 instead of rounding directly. Thus, only shifts and additions are needed to solve multiplication unit and the performance of the design is improved dramatically...