311593 2026-04-06 14:09:39 -0700 WebRTC Media capabilities do not report power efficient AV1 decode 2026-05-19 00:37:49 -0700 1 1 1 Unclassified WebKit Media Safari 26 Mac (Apple Silicon) macOS 26 RESOLVED FIXED InRadar P2 Normal --- 1 jbedwell webkit-unassigned eric.carlson jer.noble webkit-bug-importer youennf oldest_to_newest 2197380 0 jbedwell 2026-04-06 14:09:39 -0700 Overview On iOS and Mac the Safari media capabilities decoding info API (https://developer.mozilla.org/en-US/docs/Web/API/MediaCapabilities/decodingInfo) underreports AV1 capabilities. When queried for WebRTC it reports "supported" for AV1 on M3+ and A18+, but it returns false for "smooth" and "powerEfficient". Generally the "smooth" and "powerEfficient" fields should be true when hardware decode is available, and it is. This can be an issue for web applications that attempt to select a codec that the client has hardware decode support for. Steps to Reproduce await navigator.mediaCapabilities.decodingInfo({type: 'webrtc', video: {contentType: 'video/AV1', width: 1920, height: 1080, bitrate: 10_000, framerate: 60}}) Actual Results On M3+ and A18+ devices (which have hardware AV1 decode support) AV1 is reported as "supported" but not "smooth" or "powerEfficient". Queries for other types than 'webrtc' (ex. 'media-source') seem to also underreport AV1 capabilities. Expected Results On M3+ and A18+ devices AV1 should be reported as "supported" as well as "smooth" and "powerEfficient". Build Date & Hardware Tested on iPhone 15 Pro + iOS 26.4 and M4 MacBook Pro + MacOS 26.4. Additional Builds and Platforms On M4 MacBook Pro + MacOS 26.4, Chrome 146 reports AV1 decode as "smooth" and "powerEfficient". 2199880 1 webkit-bug-importer 2026-04-13 14:10:12 -0700 <rdar://problem/174686183> 2206305 2 jbedwell 2026-04-30 10:30:37 -0700 Enabling the "WebRTC AV1 codec" feature flag does not fix this issue. 2211959 3 youennf 2026-05-19 00:25:33 -0700 AV1 for regular playback (mse here) seems to work for me: const configuration = { type: 'media-source', video: { contentType: 'video/mp4; codecs="av01.0.05M.08"', width: 1080, height: 720, bitrate: 3000000, framerate: 30 } }; 2211960 4 youennf 2026-05-19 00:25:46 -0700 https://github.com/WebKit/WebKit/pull/65110 2211963 5 ews-feeder 2026-05-19 00:37:47 -0700 Committed 313468@main (6b68426e27af): <https://commits.webkit.org/313468@main> Reviewed commits have been landed. Closing PR #65110 and removing active labels.