H26x Codec support updates for MediaRecorder

[handellm]

WebKittens

@youennf

Title of the proposal

H26x Codec support updates for MediaRecorder

URL to the spec

https://www.w3.org/TR/mediastream-recording/

URL to the spec's repository

No response

Issue Tracker URL

No response

Explainer URL

https://docs.google.com/document/d/1YijhqWaeI118xqZV6Fd-UtqWpGDc-vFfFS6Dg4JEEqc/edit?tab=t.0#heading=h.66h4vpm7o59u

TAG Design Review URL

No response

Mozilla standards-positions issue URL

mozilla/standards-positions#1174

WebKit Bugzilla URL

No response

Radar URL

No response

Description

Chromium's MediaRecorder API now supports HEVC encoding, introducing the hvc1.* codec string, and adds new codec strings (hev1.* and avc3.*) supporting variable resolution video in MP4.

Support for HEVC platform encoding was added in WebCodecs in Chromium M130. As a follow-up, support has been added to the MediaRecorder API in Chromium. The API now supports both MP4 and Matroska muxer types with different HEVC and H.264 mime type specifications. HEVC encoding is only supported if the user's device and operating system provide the necessary capabilities.

Work on the Chromium side is being tracked here.