Face focus coding under H.263+ video coding standard

In this paper, we present a new method to enhance image quality at face region of head and shoulder type image sequence and to shorten processing latency to achieve synchronization between lip movement and voice (lip sync). The new method can significantly improve image quality at face region and reduce frame skip operation during high movement image coding. Improvement is done by allocating more bits budget to the face region, where the centre of perceptual interest point usually located. Total number of bits of dynamically change background region is compressed by applying temporal filter to suppress background noise. We design a new fast rate control based on non-zero coefficient evaluation to shorten compression latency. The experimental result shows the increment of face region's PSNR by around 2 dB, the decreasing of skipping operation around 60 frames during encoding of 382 frames of highly movement video sequence and the advantage of having a very small compression latency around 3 frames which can resolve the lips sync problem.