On Sat, 28 Oct 2023 12:50:14 +0200 Niklas Haas <ffm...@haasn.xyz> wrote: > On Fri, 27 Oct 2023 23:01:25 +0200 Michael Niedermayer > <mich...@niedermayer.cc> wrote: > > On Fri, Oct 27, 2023 at 07:04:42PM +0200, Niklas Haas wrote: > > > From: Niklas Haas <g...@haasn.dev> > > > > > > This code, as written, skips sws_init_context if scale->in_range was not > > > set, even if scale->in_frame_range is set to something. So this would > > > hit the 'no sws context' fast path in scale_frame and skip color range > > > conversion even where technically required. This had the effect of, in > > > practice, effectively applying limited/full range conversion if and only > > > if you set e.g. a nonzero yuv color matrix, which is obviously > > > undesirable behavior. > > > > > > Second, the assignment of out->color_range inside the branch would fail > > > to properly propagate tags for any actually applied conversion, for > > > example on conversion to a forced full range format. > > > > > > Solve both of these problems and make the code much easier to understand > > > and follow by doing the following: > > > > > > 1. Always initialize sws context on get_props > > > 2. Always use sws_getColorspaceDetails + sws_setColorspaceDetails to > > > fix the conversion matrices per-frame. > > > 3. Rather than testing if the context exists, do the no-op test after > > > settling the above values and deciding what conversion to actually > > > perform. > > > --- > > > libavfilter/vf_scale.c | 186 +++++++++++++++++------------------------ > > > 1 file changed, 76 insertions(+), 110 deletions(-) > > > > This breaks > > tickets/2939/lena.jpg > > > > (color looks slightly wrong compared to reference lena image) > > How do I reproduce this? I tested with: > > ffmpeg -i lena.jpg lena.png > > But the resulting checksum was identical before and after this commit.
Nvm, I see the issue. Actually, the bug is in patch 1 - the logic is insufficient to cover all cases, since ff_sws_init_range_convert is never re-called after changing range. I will rewrite that commit, which should fix this one also. _______________________________________________ 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".
