The Design Of H.264 Real-Time Entropy Decoder

H.264 is the video compression standard released by ITU-T/ISO in March 2003. At the beginning of the publication, due to its excellent compression performance, H.264 has been widely paid attention to and was called the next-generation video compression standard. However, its higher performance brought a higher complexity along, which made it more difficult to use simple software solutions to achieve real-time HD video encoding and decoding. So, do more widely research on H.264 hardware solutions became necessary.Firstly ,the parse theories of entropy decoder , including bitstream structure ,CAVLC parse theory and exp-golumb parse theory, were deeply researched in this paper and the theoretical foundation of entropy decoder were constituted by these. Secondly, based on basic methods of ASIC design, the whole entropy decoder was partitioned many functional modules and as much as possible reused these modules. According to the above research findings, a high-performance entropy decoder was designed in this paper. In this entropy decoder, the design emphasis was placed on CAVLC decoder and a high speed decoder structure was also designed in this paper. On the point of parsing speed, compared with other decoders, this CAVLC decoder had great advantage. Thirdly, considering the actual situation of the video decoder, verification strategy whose golden module was JM10.1 was proposed, and under this strategy a automatic simulation verification platform was designed by Perl. The entropy was verified on this platform and proved no problem on functional points. Finally, we did synthesis and generated gate-level netlist based on hjtc 180nm CMOS technology library. Also, we did formal verification on the gate-level netlist and the results proved that the RTL code and gate-level netlist had the same function.Through the synthesis and performance analysis, we had known that the clock frequency to achieve was 79.49MHz and the number of clock cycle was 12 when decoded the 4×4 block in the worst case. All of these were higher than the basic requirement of 1080p real-time decoding and the results showed that the entropy decoder satisfied the real time decoding requirement of the 1080p(@30Hz) videos.