Intent to Ship: AV1 Still Image File Format (AVIF)

[Jon Bauman]

As of March 18, 2021, I intend to turn AVIF on by default all platforms in
Firefox 88. It has been developed behind the image.avif.enabled preference.
Though there's a good chance it'll be delayed until Firefox 89, depending
on some external factors.

AVIF is an image format based on the AV1 video codec
<https://en.wikipedia.org/wiki/AV1> from the Alliance for Open Media
<https://aomedia.org/>. AV1 support shipped in release 55
<https://bugzilla.mozilla.org/show_bug.cgi?id=av1> and is currently
supported in Chrome, but not Safari. The Chromium issue for AVIF support is
960620 <https://bugs.chromium.org/p/chromium/issues/detail?id=960620>.
Chrome shipped AVIF support in version 85 in August 2020. Among other
chromium-based browsers, Opera shipped in version 71 in September, 2020 and
Egde has yet to ship AVIF support. Safari has not shipped AVIF support yet
and has released no plans, but Apple is an active member of AOM and
initial AVIF
support recently landed in Webkit
<https://bugs.webkit.org/show_bug.cgi?id=207750>. However, Safari is
unlikely to ship AVIF support until it appears in macOS. More details on
support in other browsers are available at https://caniuse.com/avif.

Bug to turn on by default:
https://bugzilla.mozilla.org/show_bug.cgi?id=1682995.

We are choosing to ship AVIF as an MVP with some features not yet
implemented, notably animations/image-sequences, grid-based image support,
image transforms (e.g., rotation, mirroring, etc.) and 10- and 12-bit image
support. Full details of what we intend to complete and leave incomplete
before shipping with AVIF enabled by default can be seen in the dependency
tree
<https://bugzilla.mozilla.org/showdependencytree.cgi?id=1443863&hide_resolved=1>
for the AVIF meta bug <https://bugzilla.mozilla.org/show_bug.cgi?id=1443863>
.

This feature was previously discussed in this "Intent to implement" thread
<https://groups.google.com/g/mozilla.dev.platform/c/bIM8ZaFS-d8/m/6yp2IXPlAQAJ>
.