H264编码器关键算的实现和优化研究.docx

浙江大学硕士学位论文Abstract 浙江大学硕士学位论文 Abstract H．264／AVC is video coding standard developed by ITU·T and Moving Picture Experts Group(MPEG)together．Comparing with other existing coding standards．H．264 achieves better compression performance and has better network adaptability．However these advantages are obtained by increasing computational complexity which leads more requirements storage and processing capability of hardware．Due to the above．how to design high performance coder becomes important problem in academic and industrial field Motion compensation is key component of H．264 encoder through which redundancies of successive frame be remove effectively．Due to the of variable block partition modes and quarter-pixel accuracy motion estimation the computational complexity is highly increased and it consumes 60％(1 reference frame)to 80％(5 reference frames)of the total encoding time of the whole encoding time of H．264 encoder．In order to reduce the computational complexity of fast motion estimation，and avoid the local minimum problem caused by small diamond search，a motion estimation algorithm based adaptive search pattem Was proposed．This algorithm chooses search pattern adaptively depending on副D changing speed and the temporal relativity in video sequence．Experimental results demonstrated that by using this algorithm the encoded bit-rate increases only士o．6％and searching points is reduced to 72％77％and 83-86％which compared with diamond search and hexagon-based search respectively．In the situation of reducing searching points this algorithm avoids local minimum problem． The H．264 encoding process of every block contains quantization，transform inverse—quantization，inverse-transform and evaluation of SAD．Lots of the processes in those algorithms treat in parallel．This paper 64-bit and 1 28一bit SIMD instructions to optimize those algorithms and bring parallel algorithm which process the transform of two 4x4 blocks at once．This paper also introduces algorithm for deblocking，whi