Complexity assisted consistent quality rate control for high resolution H.264 video conferencing

Video based multimedia services are showing major growth in recent years. Though the video coding recommendation ITU-T H.265/HEVC is in operating state, the majority of real-time video applications including video conferencing and live streaming of events rely mainly on less computationally intensive H.264/AVC coding standard which is well established among video industry. Rate control algorithms are indispensable for delivering superior quality video over limited bandwidth connections. In this paper, we propose a rate control technique which provides consistent quality video output over time in a limited bandwidth video conferencing scenario. Using the concept of video traffic prediction and linear complexity model, we compute the complexity of the video sequence in real time. We present a better estimate of quantization parameter at the GOP (group of picture) layer. Our proposed method maintains similar quality for reconstructed video when compared to rate control scheme of JM 19.0 implemented in real-time video conferencing system with restricted quality variation. On an average, 22% improvement has been observed in terms of standard deviation of frame PSNR values when compared to JM 19.0 rate control scheme implemented in high resolution video conferencing scenario.