Encoding DCT coefficients based on rate-distortion measurement

We propose a rate-distortion optimization algorithm that selects the quantization parameter and adjusts the level of the quantized DCT coefficients based on a rate-distortion measurement to achieve better video quality under a bit-rate constraint. The bit streams generated by the algorithm conform to the standards. The results show that the algorithm can achieve up to about 2.5-dB peak signal-to-noise ratio improvement compared to H.263+ TMN8 at the same bit rate. (C) 2001 Academic Press.