视频编码线性码率控制模型

A Linear Rate Control Model for Video Coding

为提高视频编码码率控制的性能,通过理论推导及实验验证提出了一种新的视频编码码率控制模型。通过该模型,编码器可以直接确定量化参数(Quantization Parameter,QP),而不必计算量化步长(Quantization Step,Qstep),进而避免了由Qstep确定QP过程中的舍入误差,提高了码率控制的准确性。实验结果表明,与H.264/AVC采用的码率控制方法相比,提出的模型可使跳帧发生的概率更低,恢复视频的质量更稳定,实际码率与目标码率之间的偏差更小,同时,还能获得更高的峰值信噪比。

In order to improve the performance of rate control, a linear rate control model is proposed through theoretical analysis and experiments. With the proposed model, the quantization parameter （QP） can be calculated directly while avoiding the computation of quantization step （Qstep）. Therefore, the round - off error producing by converting Qstep to QP, is avoided and the coding rate can be controlled accurately. Experimental results show that compared with the rate control scheme utilized in H. 264/AVC, the proposed model can make the probability of frame skip lower, the quality reconstructed more stable, the mismatches between the actual coding bit-rates and the target bit-rotes smaller. At the same time,higher PSNR（Peak Signal to Noise Ratio） can be achieved.