Design Of Real-Time HD Transcoder Based On TILERA Many-Core Processor

Along with the rapid progress of network and personal communicationterminals, our requirement for online video is becoming more and moreurgent. H.264/MPEG-4AVC is the ideal choice of online video for its highcompression ratio as well as its high fidelity. Meanwhile, for historicalreasons, many video sources are still encoded in MPEG2. If an efficientmethod of converting MPEG2video to H.264video is implemented, thenthe H.264video sources will be greatly enriched.Since there is no practical algorithm for transcoder currently, mostMPEG2-to-H.264Transcoders are implemented in a “Full Decode FullEncode” way. Due to the complexity of H.264encoding, it will take agreat mount of computing to implement a multi-channel real-timetranscoder, which is based on a MPEG2decoder and H.264encoder.Parallel computing offers a practical solution to real-time transcoder.This paper firstly introduces some basics of parallel computing and basedon this, some analysis of current research on parallel encoder/decoder is provided. A more efficient parallel programming module, Work Pool, isthen introduced. This is the foundation of our parallel decoder and encoder.Based on the parallel decoder and encoder previously analyzed, togetherwith the input module that supports large file reading, the output modulethat supports streaming of bit stream, and the cascading module of thecodec, our transcoder is finally constructed.Our experiment indicates that the MPEG2decoding module is of greatparallel extendibility. Due to its high complexity, H.264encoding moduledoes not have a fine parallel extendibility compared with decode module.But it still has a good interval of linear parallel acceleration ratio. Ourtranscoder has a very limited parallel extendibility since some waiting loopis introduced during its implementation. However, the transcoding speedof the transcoder is still enough for implanting three-channel transcodingsystem on the Tilera GX36processor.