On Sat, Jul 2, 2022 at 2:35 AM Anton Khirnov <an...@khirnov.net> wrote: > > Quoting Vignesh Venkatasubramanian (2022-06-30 23:04:34) > > Parse the alpha channel for still AVIF images and expose it as a > > separate track. This is the simplest way of supporting AVIF alpha > > channel in a codec independent manner (similar to how ffmpeg > > supports animated AVIF with alpha channel). > > > > One can use the alphamerge filter to get a transparent image with > > a single command. For example: > > > > ffmpeg -i image_with_alpha.avif -filter_complex alphamerge > > image_with_alpha.png > > > > Signed-off-by: Vignesh Venkatasubramanian <vigne...@google.com> > > --- > > libavformat/isom.h | 1 + > > libavformat/mov.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 67 insertions(+) > > I am against this patch, this is a digusting hack. > > These are not two streams, it is a single stream and should be exposed > as such. >
Yes, while it is a hack, it is also the simplest way of supporting AVIF images with alpha. Since AVIF alpha images require two separate decoders, i could not think of any other solution that does not involve modifying the underlying av1 codec itself. If there are any alternative solutions where we can expose a single stream that needs two codecs, then i am open to implementing that. Otherwise, this solution improves the current situation where there is no way for the user to extract the alpha channel (albeit in a hacky way). > -- > Anton Khirnov -- Vignesh _______________________________________________ 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".
