Complexity control for high-efficiency video coding by coding layers complexity allocations

Abstract

The latest video compression standard, high-efficiency video coding (HEVC), provides quad-tree structures of coding units (CUs) and four coding tree depths to facilitate coding efficiency. The HEVC encoder considerably increases the computational complexity to levels inappropriate for video applications of power-constrained devices. This work, therefore, proposes a complexity control method for the low-delay P -frame configuration of the HEVC encoder. The complexity control mechanism is among the group of pictures layer, frame layer, and CU layer, and each coding layer provides a distinct method for complexity allocation. Furthermore, the steps in the prediction unit encoding procedure are reordered. By allocating the complexity to each coding layer of HEVC, the proposed method can simultaneously satisfy the entire complexity constraint (ECC) for entire sequence encoding and the instant complexity constraint (ICC) for each frame during real-time encoding. Experimental results showed that as the target complexity under both the ECC and ICC was reduced to 80% and 60%, respectively, the decrease in the average Bjontegaard delta peak signal-to-noise ratio was ∼0.1 dB with an increase of 1.9% in the Bjontegaard delta rate, and the complexity control error was ∼4.3% under the ECC and 4.3% under the ICC.