gm8136数据手册

GM8136 数据手册 The MPEG4/JPEG codec includes the hardware engines to accelerate the computation-intensive tasks, such as the motion estimation, DCT/IDCT, quantization/inverse quantization, and motion compensation. By initializing the control registers of this codec, MPEG4/JPEG codec will automatically perform the motion estimation calculation task for 16x16 or 8x8 block. MPEG4/JPEG codec will also automatically perform the DCT/quantization, IDCT/inverse quantization, AC/DC prediction, zigzag scan, and VLC/VLD calculation task for a macro-block. Therefore, CPU loading can be released from the timing critical tasks in the video encoding process. The features of the MPEG4/JPEG engine include:  Compliant with MPEG4 (ISO/IEC 14496-2) simple profile L0 ~ L3 standards with resolutions of subQCIF, QCIF, CIF, VGA, D1, and 720p with steps of 16 units  Compliant with JPEG (ISO/IEC 10918-1) baseline standard  Includes hardware engines for motion estimation/motion compensation, DCT/IDCT, quantization/inverse quantization, AC/DC prediction, and coding/decoding with variable length  Uses local memory controller to control local memory shared by CPU, MPEG4/JPEG codec, and DMA master  Uses DMA controller to control data transfers between system memory and local memory  Supports automatic power-down mechanism to reduce power consumption  Motion estimation search range: -16 ~ +15.5 (Optionally -32 ~ +31) with half-pixel accuracy  Supports short video header (H.263 baseline)  Supports H.263/MPEG/JPEG quantization methods