Foreground/background video coding using H.261
Douglas Chai, King Ngi Ngan · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1998
This research addresses the use of face segmentation to improve the subjective quality of videophone sequence encoded by the H.261-compliant coder. In this approach, each frame of the input video sequence is first segmented into two regions, namely, foreground and background. These regions are then encoded using the same coder but with different rate control and quantization level. In this way, the image quality of the more important foreground region can be improved by encoding it with more bits at the expense of background image quality. In this paper, we present a summary of the face segmentation technique required by this approach and then describe the implementation of this foreground/background (FB) coding scheme on the H.261 framework. The discriminatory quantization process and a new rate control strategy for the FB regions are also discussed. In addition, the performance of the FB coding scheme was evaluated by some experimental result carried out on the typical videophone sequences.