Research And Implemenation Of MPEG-4 Decoding And JPEG Encoding Based On DSP

Along with the progress of mobile communication and multimedia technologies,people's requirements to communication are not limited to traditional speech service,they demand multimedia information services such as video and audio,with higher quality.In multimedia communication,a remarkable characteristic of video information is its huge amount of data and high processing complexity.Existing mobile terminal commonly uses DSP as its core processor,DSP has advantages in data processing,but it's not good at system processing and control.The 3rd generation mobile communication terminal requires more complicated services,like real-time video communication,thus requires higher processing ability of DSPs.MPEG-4 is a standard of "video-audio object", passed in December, 1999. MPEG-4 is a coding method based on the content of images, producing high compression ratio. It's designed to provide good quality in the case of very low bandwidth, so MPEG-4 is very suitable to be used in mobile multimedia communication. TI's OMAP5910 dual-core processor is adopted as the core processor of the wireless terminal, its DSP core is used to do data processing operations, its ARM core is used to handle control operations.Based on the DSP core of OMAP5910-TMS320C5510, a detailed explanation of the migration and optimization to MPEG-4 video decoder is introduced, after optimization, the decoder can realize real-time decoding and displaying QVGA video with the frame rate 25f/s, when C5510 works with the frequency of 150MHz, just occupies about 73% of CPU's cycles.Based on this work, the MPEG-4 decoder is successfully migrated to DM642 platform, taking advantage of its vigorous assembly instruction set, assembly language optimization was implemented to the key modules of the decoder. After optimization, the decoder can realise real-time decoding of 720×576 video with frame rate 25f/s, the CPU occupation rate only reaches about 45%.Optimization of a JPEG encoder based on TMS320C6203 DSP and the realization of a JPEG decoder capable of error handling is also discussed in this paper.