Meta shares a detailed technical account of deploying AV1 for real-time video calls across Messenger and WhatsApp at scale. Key challenges addressed include encoder complexity (a custom low-complexity encoder with presets comparable to H.264), decoder selection (dav1d chosen for power efficiency), binary size constraints, and ML-based device eligibility for the fragmented Android ecosystem. The post covers adaptive codec switching mechanisms — including encoder preset adjustment and peer decoding latency-aware fallback to H.264 — as well as an asymmetric codec design where mid-range devices receive AV1 but encode H.264. On call quality, Meta details VBV-based rate control to prevent bitrate overshoots, adaptive temporal layers for loss resilience, and a Long-Term Reference (LTR) frame system with explicit RTP header extensions for fast recovery from packet loss. AV1 now runs on the majority of Meta's mobile RTC devices, with group call support and broader hardware AV1 adoption cited as next steps.
