Parallel CABAC for low power video coding

With the growing presence of high definition video content on battery-operated handheld devices such as camera phones, digital still cameras, digital camcorders, and personal media players, it is becoming ever more important that video compression be power efficient. A popular form of entropy coding called context-based adaptive binary arithmetic coding (CABAC) provides high coding efficiency but has limited throughput. This can lead to high operating frequencies resulting in high power dissipation. This paper presents a novel parallel CABAC scheme which enables a throughput increase of N-fold (depending on the degree parallelism), reducing the frequency requirement and expected power consumption of the coding engine. Experiments show that this new scheme (with N=2) can deliver ~2x throughput improvement at a cost of 0.76% average increase in bit-rate or equivalently a decrease in average PSNR of 0.025 dB on five 720 p resolution video clips when compared with H.264/AVC.