Bidirectional Learned Facial Animation Codec for Low Bitrate Talking Head Videos
Riku Takahashi, Ryugo Morita, Fuma Kimishima, Kosuke Iwama, Jinjia Zhou
TL;DR
The paper addresses low-bitrate talking-head video compression by replacing single-keyframe approaches with a bidirectional framework that exploits past and future keyframes and a compact auxiliary stream. It introduces BRG-ASE for adaptive auxiliary-frame enhancement and BRG-VRec for bidirectional keyframe-based reconstruction, achieving substantial bitrate reductions while preserving visual quality. The approach demonstrates state-of-the-art performance on VoxCeleb with lower bitrates than both animation-based codecs and conventional standards like VVC. This enables more efficient, stable talking-head video communication in bandwidth-limited scenarios.
Abstract
Existing deep facial animation coding techniques efficiently compress talking head videos by applying deep generative models. Instead of compressing the entire video sequence, these methods focus on compressing only the keyframe and the keypoints of non-keyframes (target frames). The target frames are then reconstructed by utilizing a single keyframe, and the keypoints of the target frame. Although these unidirectional methods can reduce the bitrate, they rely on a single keyframe and often struggle to capture large head movements accurately, resulting in distortions in the facial region. In this paper, we propose a novel bidirectional learned animation codec that generates natural facial videos using past and future keyframes. First, in the Bidirectional Reference-Guided Auxiliary Stream Enhancement (BRG-ASE) process, we introduce a compact auxiliary stream for non-keyframes, which is enhanced by adaptively selecting one of two keyframes (past and future). This stream improves video quality with a slight increase in bitrate. Then, in the Bidirectional Reference-Guided Video Reconstruction (BRG-VRec) process, we animate the adaptively selected keyframe and reconstruct the target frame using both the animated keyframe and the auxiliary frame. Extensive experiments demonstrate a 55% bitrate reduction compared to the latest animation based video codec, and a 35% bitrate reduction compared to the latest video coding standard, Versatile Video Coding (VVC) on a talking head video dataset. It showcases the efficiency of our approach in improving video quality while simultaneously decreasing bitrate.