Based On Fpga H.264 Entropy Coding Research And Design

As one of the video coding standard of the next generation, H.264/AVC is developed jointly by ITU and ISO. There are some new technologies on video compression adopted in this new standard, such as multi-mode inter prediction, 1/4 fractional pixel motion estimation, integer transformation, motion compensation with flexible block measurement, CABAC, CAVLC,etc. Among those technologies, CABAC and CAVLC are of entropy encoding.Entropy encoding is in the hardcore of H.264 standard, therefore, the research on and the design of the core module of entropy encoding in H.264 are significant, and my dissertation is to fulfill the task of designing and researching based on FPGA.In CABAC, the production of the prior research on video coding standards is taken, the drawbacks of the known entropy coding schemes for hybrid block-based video coding are also circumvented, the adaptive binary arithmetic coding technique is combined with a well-designed set of context models, in the principle of alphabet reduction, an additional binarization stage is employed for all nonbinary valued symbols, it enables context modeling on a subsymbol level, as a result , the number of probability model is reduced and the adaptability of the model is enhanced.The coding block is of size 4x4 in H.264, the coefficients in block are characterized by gathering at low frequency zone and small-sized level, and has a great number of sequential zeros. Accordingly, the run-level coding which contribute to the optimization of coding is adopted in CAVLC.Several controlling and indicating signals are set in each module design according to various conditions, such as the codeword size controlling signals which are used to control storage and to make tight connections of the output between sub-modules.In this dissertation, the updating of H.26L standards and the development of the technology in video compression are introduced at first, then are the dynamics and significance of the research on it, and a brief introduction of the development kits and platform is made. After that, the design and implementation of the core module of entropy coding in H.264 are expatiated, moreover, the module of renormalization, the setting of the value Model_number, the formula of k-th order Exp-Golomb codes in CABAC and the coding principle of the non-zero coefficients in CAVLC are also deeply discussed. Furthermore, a comparison of coding performance between CAVLC and CABAC is made, and the hardware simulation of the codes for entropy coding on the developing board is showed. At the end of this dissertation, a conclusion is made.The main items of my work done in the project are as follows:1, analyze and explain the coding principle of the non-zero coefficient in CAVLC ;2, go through the design and implementation on CAVLC module with Verilog HDL;3, analyze and explain the k-th order Exp-Golomb codes in CABAC;4, go through the design and implementation on CABAC module with Verilog HDL;5, analyze and verify the coding results, the module of renormalization and the setting of the value Model_number;6, debug the codes for entropy encoding on the developing board of AlteraFPGA.