Scene adaptive bit-rate control method on MPEG video coding
Myungjin Lee, Soon-kak Kwon, Jae‐Kyoon Kim · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1997
This paper presents a simple bitrate control method to percent the abrupt quality degradation after scene change. After scene change, the quality degradation occurs due to the poor temporal prediction between pictures before and after scene change. We predict the coding complexity of picture using the spatial variance before DCT and spectral flatness measure. From the predicted coding complexity, we show that the rate-distortion relation of image can be approximated to exponential function. When scene changes, picture target bit is adjusted in the direction to minimize the distortion in a GOP using the rate-distortion relations for each P-picture. Since the bit shortage could be occurred, proposed method extends the current GOP to the next. The algorithm can be applied to the existing MPEG codecs and real-time applications easily. Compared with the MPEG-2 TM5 rate control algorithm, proposed algorithm shows 0.5 to approximately 2.5 dB gain in PSNR and a small fluctuation in quality after scene change.