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ed83a3a5bd
Since introducing the various packed formats used by VAAPI (and p012), we've noticed that there's actually a gap in how av_find_best_pix_fmt_of_2 works. It doesn't actually assign any value to having the same bit depth as the source format, when comparing against formats with a higher bit depth. This usually doesn't matter, because av_get_padded_bits_per_pixel() will account for it. However, as many of these formats use padding internally, we find that av_get_padded_bits_per_pixel() actually returns the same value for the 10 bit, 12 bit, 16 bit flavours, etc. In these tied situations, we end up just picking the first of the two provided formats, even if the second one should be preferred because it matches the actual bit depth. This bug already existed if you tried to compare yuv420p10 against p016 and p010, for example, but it simply hadn't come up before so we never noticed. But now, we actually got a situation in the VAAPI VP9 decoder where it offers both p010 and p012 because Profile 3 could be either depth and ends up picking p012 for 10 bit content due to the ordering of the testing. In addition, in the process of testing the fix, I realised we have the same gap when it comes to chroma subsampling - we do not favour a format that has exactly the same subsampling vs one with less subsampling when all else is equal. To fix this, I'm introducing a small score penalty if the bit depth or subsampling doesn't exactly match the source format. This will break the tie in favour of the format with the exact match, but not offset any of the other scoring penalties we already have. I have added a set of tests around these formats which will fail without this fix.
FFmpeg README
FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides means to alter decoded audio and video through a directed graph of connected filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements color conversion and scaling routines.
Tools
- ffmpeg is a command line toolbox to manipulate, convert and stream multimedia content.
- ffplay is a minimalistic multimedia player.
- ffprobe is a simple analysis tool to inspect multimedia content.
- Additional small tools such as
aviocat,ismindexandqt-faststart.
Documentation
The offline documentation is available in the doc/ directory.
The online documentation is available in the main website and in the wiki.
Examples
Coding examples are available in the doc/examples directory.
License
FFmpeg codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.
Contributing
Patches should be submitted to the ffmpeg-devel mailing list using
git format-patch or git send-email. Github pull requests should be
avoided because they are not part of our review process and will be ignored.