Multi-resolution Encoding for HTTP Adaptive Streaming using VVenC

TL;DR

The paper addresses the computational burden of producing multiple HAS representations using the VVC-based VVenC encoder. It proposes MEVHAS, a two-stage multi-resolution encoding approach that uses low-resolution representations as references to accelerate high-resolution partitioning across all required bitrates. Partition data from the low-resolution layer is interpolated to guide high-resolution CU sizing, with selective RDO skipping to reduce complexity. Experiments on 130 Inter4K videos show average encoding time reductions of about 17% and a BDBR/BDT of 0.12, outperforming the fast preset while maintaining near-medium compression efficiency, offering practical benefits for HAS deployment.

Abstract

HTTP Adaptive Streaming (HAS) is a widely adopted method for delivering video content over the Internet, requiring each video to be encoded at multiple bitrates and resolution pairs, known as representations, to adapt to various network conditions and device capabilities. This multi-bitrate encoding introduces significant challenges due to the computational and time-intensive nature of encoding multiple representations. Conventional approaches often encode these videos independently without leveraging similarities between different representations of the same input video. This paper proposes an accelerated multi-resolution encoding strategy that utilizes representations of lower resolutions as references to speed up the encoding of higher resolutions when using Versatile Video Coding (VVC); specifically in VVenC, an optimized open-source software implementation. For multi-resolution encoding, a mid-bitrate representation serves as the reference, allowing interpolated encoded partition data to efficiently guide the partitioning process in higher resolutions. The proposed approach uses shared encoding information to reduce redundant calculations, optimizing partitioning decisions. Experimental results demonstrate that the proposed technique achieves a reduction of up to 17% compared to medium preset in encoding time across videos of varying complexities with minimal BDBR/BDT of 0.12 compared to the fast preset.

Figures (6)

• Figure 1: Overview of the MEVHAS framework. A reference representation is first encoded at a lower resolution, which helps accelerate the encoding of dependent representations at higher resolutions across all bitrates.
• Figure 2: Low-resolution to high-resolution interpolation of one CTU.
• Figure 3: MEVHAS flow chart for encoding time reduction in VVenC.
• Figure 4: Bitrates of various Inter4K videos at QP 22 exceeding on average 16.8 Mbps.
• Figure 5: BDBR/BDT of Inter4k videos of various complexities.