Widevine 4.10.1582.2 adds av1 support and thus specifies av01 as a supported codec in its manifest. We don not currently recognize this string, so fail to load the CDM.

To be clear, fixing this doesn't add support for encrypted AV1 to Firefox, as we have some other plumbing to do there. Fixing this is just lets us load Widevine CDMs that support AV1.

This lets us load Widevine versions that support av1. This doesn't add encrypted
av1 support, but is one of the steps needed to do so.

https://hg.mozilla.org/mozilla-central/rev/cbb7db3f8e37

Comment on attachment 9113999 [details]
Bug 1601813 - Parse av01 codec when parsing Widevine manifests. r?dminor

ESR Uplift Approval Request

• If this is not a sec:{high,crit} bug, please state case for ESR consideration: This is required to support new versions of Widevine on ESR.
• User impact if declined: We will be unable to roll out new Widevine CDMs to ESR until we ship a new major release. The risk is that the current CDM is deactivated prior to us shipping the next major ESR, in which case the current ESR would lose the ability to play DRM protected content.
• Fix Landed on Version: 73
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): The patch is small and makes our parsing of a manifest more permissive by handling 1 additional string that may be present.
• String or UUID changes made by this patch: None.

Comment on attachment 9113999 [details]
Bug 1601813 - Parse av01 codec when parsing Widevine manifests. r?dminor

Needed to support newer Widevine CDMs on ESR. Approved for 68.5esr.

https://hg.mozilla.org/releases/mozilla-esr68/rev/e80192230208