Fast Block Structure Determination in AV1-based Multiple Resolutions Video Encoding

TL;DR

This paper introduces a fast block structure determination algorithm for AV1-based multi-resolution video encoding, significantly reducing encoding time while maintaining low bitrate increase.

Contribution

It models block structure similarity across resolutions to accelerate high resolution encoding based on low resolution results, improving efficiency.

Findings

Reduces encoding time by 30.1%-36.8%

Maintains BD-rate increase below 1.04%

Halves performance loss compared to state-of-the-art

Abstract

The widely used adaptive HTTP streaming requires an efficient algorithm to encode the same video to different resolutions. In this paper, we propose a fast block structure determination algorithm based on the AV1 codec that accelerates high resolution encoding, which is the bottle-neck of multiple resolutions encoding. The block structure similarity across resolutions is modeled by the fineness of frame detail and scale of object motions, this enables us to accelerate high resolution encoding based on low resolution encoding results. The average depth of a block's co-located neighborhood is used to decide early termination in the RDO process. Encoding results show that our proposed algorithm reduces encoding time by 30.1%-36.8%, while keeping BD-rate low at 0.71%-1.04%. Comparing to the state-of-the-art, our method halves performance loss without sacrificing time savings.