Efficient Rate Control Scheme Using Complexity of Macro Block for MPEG-2 Transcoder

When the bit rate of the compressed video sequence is reduced by a frequency domain transcoder system, the rate control scheme is very important to maintain the consistent video quality. In this paper, we propose an efficient rate control scheme based on the complexity of MB while conventional transcoding schemes use that of a picture. Since the frequency domain transcoder has to calculate the spatial activity of MB to adjust the quantization step, the process to convert the DCT data into the spatial one is required. The proposed scheme calculates the spatial activity from DCT data without converting them to pixel domain.