MPEG-4 Video Compression Algorithms Research And Its Realization Based On DSP

In the current digital days, the unremittingly developing MPEG-4 standard well meets the transimission of digital multimedia information owing to its low bit rate and high compensation. It gains an extensive use in the interactive multimedia field, such as digital-television, video telephone, real-time multimedia inspecting, mobile multimedia communication and network video server.MPEG-4 is a video compression standard based on object, which uses the second generation coding technology and has been put more and more attention in the video compression field. Nowadays, the realization of MPEG-4 video encoding based on embedded system becames the hotspot and nodus of correlation study, since the embedded video encoding system not only contains the characteristic of high-integration density, lowcost, high performance and convenience use, but also the MPEG-4 compression algorithm has the deficiency of complexity and the high real time requirement. Digital signal processor is used as main CPU in kinds of embedded systems increasingly on account of its high accuracy, high speed, low power dissipation, parallelism and high-integration density. The research work of this paper is in the service of multimedia rescue communication system, which brings forward an encoder based on the C6000 series DSP of TI(TMS320C6211) and realizes the MPEG-4 video compression.Firstly, the paper gives an outline of the video compression and basilic technologies of MPEG-4 standard. It introduces the significant algorithms of MPEG-4, including DCT, quantization, motion estimation, motion compensation, run-length encoding and arithmetic coding. Secondly, it brings to success a MPEG-4 encoder based on PC platform, then the encoder is transplanted and optimized on DSP platform. Thirdly, according to the results of statistical tools, the algorithms of the encoder which cost numerous CPU cycles are replaced with assemble codes. The algorithm structure is adjusted according to the hardware characteristics of C6211 and a certain number of the MPEG-4 algorithm are improved, for instance, the diamond search algorithm in motion estimation part and the MPEG quantization algorithm in quantization part are improved. Moreover, the paper accomplishs a MPEG-4 simple profile encoder on DSP platform, where the compressive performance of the encoder is tested and analysed. Finally, it takes a simple overview of the hardware design, mainly including the logic control part as well as the application area of the encoder.