Improving bit-rate and quality control for MPEG-2 video sources

In video compression techniques, it is very important to implement the most efficient bit allocation strategy in order to achieve the best quality with the minimum number of bits. This paper presents a new feedback/feedforward controller, for MPEG-2 coding, that dynamically tunes the quantization parameters by analysing the image sequence from a psycovisual point of view. The analysis is carried out on an 8×8 pixels block basis to determine the visual characteristic of each macroblock. This pre-analysis classifies macroblocks and assigns quantization parameters to them according to a proposed scale measuring their visual relevance. A post-analysis procedure provides the final tuning. The system generates images with higher quality with respect to the standard Test Model 5.