avformat/av1: Document actual behaviour of ff_av1_filter_obus()

Document that it can be used with a NULL AVIOContext to
get the output size in a first pass.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2022-01-16 00:00:22 +01:00
parent 396efc73e3
commit 5f973193e5