Ali266: Deployment of the H.266/VVC Codec on Youku – Architecture, Performance, and Business Impact

In January 2022, Ali266 was launched on Youku, making the platform the industry’s first to adopt the international H.266/VVC video coding standard. Real‑world operation showed that, at the same visual quality, the bitrate can be reduced by up to 40% and stall rate by 50% compared with the previous H.265/HEVC solution.

Youku, Alibaba’s core entertainment platform, supports PC, TV, and mobile terminals and offers a wide range of content forms (copyright, original, co‑production, live streaming, etc.). To stay at the forefront of video technology, Youku collaborated with Alibaba Cloud to integrate the latest H.266/VVC standard, leveraging its superior compression efficiency.

The H.266/VVC standard was jointly developed by MPEG (ISO/IEC) and VCEG (ITU‑T). Since its first official release in July 2020, it provides advanced tools for block partitioning, prediction, transform, quantization, entropy coding, and loop filtering, roughly doubling compression efficiency over H.265/HEVC.

Alibaba’s research team, led by Dr. Ye Yan, contributed nearly 100 technical proposals to the standard and built the Ali266 encoder/decoder. The encoder offers four speed presets (slow, medium, fast, faster). The “slow” preset matches the x265‑veryslow speed and achieved top rankings in the 2021 MSU Encoder Competition, saving up to 71% bandwidth while maintaining subjective quality.

Ali266 became the first publicly available real‑time 720p H.266 encoder in June 2021 and the first 1080p encoder in September 2021. Compared with x265‑medium, the “faster” preset saves more than 40% bandwidth, benefiting live streaming and video‑conference scenarios.

Mobile integration (Ali266 decoder) uses multi‑core parallelism, assembly optimizations, and memory‑access tuning to achieve smooth playback on mid‑range phones, including 4K@30 fps real‑time decoding on flagship devices. Extensive testing on Android, iOS and other devices confirmed stability (>99.95%), low latency (~8 ms), and power efficiency (10 h of H.266 playback on a full battery, saving ~1 GB of traffic).

Server‑side integration adds Ali266 encoder/decoder into Youku’s transcoding pipeline, supporting various container formats (MP4, MPEG‑TS) and enabling bitrate‑adaptive streaming. The playback core (Consumer → openSource → openDecoder → openRender) was minimally modified, allowing rapid deployment across platforms.

Business results after the January 2022 rollout include over 600,000 plays by March 23, with a 40% bitrate reduction, 50% lower stall rate, average decoding time of 8 ms, and power savings of 1 GB per 10 h of playback.

Future plans involve extending Ali266 to HDR10‑bit, free‑viewpoint, 4K‑8K, and high‑frame‑rate (60‑120 fps) content, as well as expanding from VOD to live streaming, further optimizing the codec for broader device ecosystems.