Adaptation of video encoders for improvement in quality

International video compression standards provide bit-stream syntax for decoders. The standards offer enough flexibility to control various features at encoding so that continuous improvement in the quality and performance of encoders can take place. Innovative algorithms can be used in motion estimation (ME), rate control, usage of interlaced tools, scene change detection etc. In this paper. algorithms to adapt Group Of Pictures (GOP) length, to adapt the number of B pictures, to select the scan table used in variable length encoding depending on scene content, and to adapt f-code used in encoding the motion vectors are described. In other words, these algorithms dynamically adapt the encoding parameters so that best quality is achieved for any kind of sequence. The complexity of these algorithms is very minimal as the algorithms use the output of different modules in encoding process. The proposed algorithms can be used in standards such as MPEG-2, MPEG-4, MPEG-1 and H.263+ etc. The proposed algorithms are implemented in our MPEG-2 encoder and performance of the algorithms is presented for the same.