A SAQD-domain source model unified rate control algorithm for H.264 video coding

Rate control aims to adapt coding bit rate to the fluctuating network bandwidth. Since the bit rate at the encoder is determined by the final residual produced after quantizing DCT coefficients, we managed to set up exact relations among coding bit rate, the sum of absolute quantized difference (SAQD) and quantization step, proposed a novel SAQD-domain source model with an analytic justification, and unified it with an easy rate control algorithm for H.264 video coding. The proposed model shows a quite pleasing goodness-of-fit. Experimental results demonstrate that, compared with rate control mechanism suggested in H.264 proposal, the proposed model unified rate control algorithm yields the desired rate with much smaller deviations (less than 0.22% of the target rate), and provides much better reconstructed visual quality by giving a maximum coding gain up to 0.84dB and an average 0.59dB with smaller PSNR variation.