On Wed, Jun 1, 2022 at 11:06 AM Vignesh Venkatasubramanian <vigneshv-at-google....@ffmpeg.org> wrote: > > AVIF specification allows for alpha channel as an auxiliary item (in > case of still images) or as an auxiliary track (in case of animated > images). Add support for both of these. The AVIF muxer will take > exactly two streams (when alpha is present) as input (first one being > the YUV planes and the second one being the alpha plane). > > The input has to come from two different images (one of it color and > the other one being alpha), or it can come from a single file > source with the alpha channel extracted using the "alphaextract" > filter. > > Example using alphaextract: > ffmpeg -i rgba.png -filter_complex "[0:v]alphaextract[a]" -map 0 -map "[a]" > -still-picture 1 avif_with_alpha.avif > > Example using two sources (first source can be in any pixel format and > the second source has to be in monochrome grey pixel format): > ffmpeg -i color.avif -i grey.avif -map 0 -map 1 -c copy avif_with_alpha.avif > > The generated files pass the compliance checks in Compliance Warden: > https://github.com/gpac/ComplianceWarden > > libavif (the reference avif library) is able to decode the files > generated using this patch. > > They also play back properly (with transparent background) in: > 1) Chrome > 2) Firefox (only still AVIF, no animation support) > > Signed-off-by: Vignesh Venkatasubramanian <vigne...@google.com> > --- > libavformat/movenc.c | 188 +++++++++++++++++++++++++++++-------------- > libavformat/movenc.h | 4 +- > 2 files changed, 130 insertions(+), 62 deletions(-) >
lgtm. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
