Add support for AVIF image files

[jficz]

What file type
image/avif

What application is using it
Not too many yet.

Please attach a sample file here (or a direct external link to one)
avif sample file

Browser support isn't full yet but there's https://github.com/Kagami/avif.js for instance which works just fine.

AVIF-compressed files can also be embedded inside HEIF containers so support might also be added as part of #4

[skjnldsv]

Supported browsers

With native decoder:

Chrome Desktop 70+
Firefox 63+ (with media.av1.enabled activated)
Firefox for Android 64+ (with media.av1.enabled and media.av1.use-dav1d activated)
Edge 18+ (with AV1 Video Extension installed)
Bromite 71+

With AV1 polyfill:

Chrome 57+
Firefox 53+
Edge 17+
Safari 11+

[szaimen]

This should already be possible with the memories app iirc

[cromefire]

Nope doesn't find it as an image it seems.

Even if there was no resizing or previews or anything available yet it would still be nice to at least see the current image in all supported browsers (which is any browser except Edge right now which will finally enable it in January).

[cromefire]

Supported browsers

With native decoder:

Chrome Desktop 70+
Firefox 63+ (with media.av1.enabled activated)
Firefox for Android 64+ (with media.av1.enabled and media.av1.use-dav1d activated)
Edge 18+ (with AV1 Video Extension installed)
Bromite 71+

With AV1 polyfill:

Chrome 57+
Firefox 53+
Edge 17+
Safari 11+

Starting with the next edge version if everything goes according to plan, every major browser will have avif support natively. So I guess the polyfill shouldn't be needed anymore.