Bonjour TAG,

I'm requesting a TAG review of:

• Name: Support codec and container switching with MSE using SourceBuffer.changeType()
• Specification URL: WICG Media Source Extensions codec-switching incubation editor's draft, containing changeType() specification and related algorithm updates
• Explainer, Spec issue, and Demo, in Chrome 69+, first enable chrome://flags#enable-experimental-web-platform-features
• Tests: Added to existing MSE suite: media-source/mediasource-changetype.html and media-source/mediasource-changetype-play.html
• Primary contacts: @wolenetz. (@jyavenard also directly participated in the feature's design and incubation.)

Further details (optional):

• Relevant time constraints or deadlines: This feature was requested long before MSE REC, and the use case persists. Some MSE users, such as YouTube, have strong interest in using it ASAP.
• I have read and filled out the Self-Review Questionnare on Security and Privacy. The assessment is here.
• I have reviewed the TAG's API Design Principles

Firefox 63+ contains an implementation of this new API (SourceBuffer.changeType()) on-by-default. Chrome 69+ contains an implementation conditioned by chrome://flags#enable-experimental-web-platform-features, and the intent-to-ship it on-by-default is currently pending approvals.

Please go by the editor's draft, not the explainer (the explainer predated the spec, and some small things have changed such as changeType() is a void, not boolean method; it throws if called in bad state or if the change isn't supported.) I'll be updating the explainer this week to make it reflect the spec more precisely.

We'd prefer the TAG provide feedback as (please select one):

• open issues in our Github repo for each point of feedback
• open a single issue in our Github repo for the entire review
• leave review feedback as a comment in this issue and @-notify [wolenetz, jyavenard]

Thank you!