Region Based Minimization of Quantization Error Propagation in Variable Bitrate Video

A bit allocation method is proposed to minimize the propagation of quantization error and thereafter to increase the average quality of encoded video in variable bitrate video applications. In comparison with constant bitrate video, a variable bitrate video can provide better visual quality and coding efficiency for compressed video. Furthermore, while more variation in bitrate is possible we have additional degrees of freedom to control the encoding parameters. The proposed bit allocation algorithm takes advantage of this freedom in variable bitrate video to minimize the propagation of quantization error. The proposed method is implemented by special inter/P macroblocks namely SPPMB (Special P Macroblock) independently of rate control algorithm. The SPPMB is an inter MB (Macroblock) with a high relative bit budget and with special spatial and temporal location. A normal inter MB is replaced with a SPPMB if some conditions are met. The SPPMB can be used in different encoding standards including H.263, MPEG-4 and H.264/AVC standards. The experimental results show that the proposed bit allocation method can considerably increase the total average quality of variable bit rate encoded video.