tree 18134a108434f09e5eff1af2929cc29d63b9e84f
parent 585777ead5c6dbf4a35ef0d70be7e45baaca3ad8
author Vignesh Venkatasubramanian <vigneshv@google.com> 1684875561 -0700
committer Vignesh Venkatasubramanian <vigneshvg@users.noreply.github.com> 1685033041 -0700

Force keyframe for alpha if color is a keyframe

When the encoder supports it (as of now only libaom does),
disable lagged output when encoding animated images with alpha
channel. When the utput of the color planes is a keyframe, force
a keyframe on the alpha channel as well.

While the spec does not enforce this, and the libavif decoder can
handle files without this requirement just fine, this change is
still an enhancement because most decoders look at whether or not
the color frame is a keyframe to determine seek points.

Fixes: Issue #841