Implementation of video encoder with real-time constant- and variable-bit-rate control

Digital television (DTV) encoder is a very important part of DTV broadcast chain. Most real-time MPEG-2 encoders are designed to perform in a constant-bit-rate (CBR) mode. But an even better compressed stream can be created by employing a variable-bit-rate (VBR) encoding algorithm. VBR can be exploited as a means of achieving statistical multiplexing for digital broadcast satellites. This paper suggests an implementation procedure of DTV video encoder and proposes a novel VBR bit-allocation strategy that could be implemented in this encoder system. Firstly, a real time VBR bit-allocation strategy is deduced. Secondly, system implementation of DTV video encoder and our real time VBR bit-allocation strategy is discussed. Finally, Experimental results demonstrate that our proposed VBR encoder displays a better performance than the CBR encoder.