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The old "API" that signaled rotation as a metadata value has been replaced by DISPLAYMATRIX side data quite a while ago. There is no reason to make muxers/demuxers/API users support both. In addition, the metadata API is dangerous, as user tags could "leak" into it, creating unintended features or bugs. ffmpeg CLI has to be updated to use the new API. In particular, we must not allow to leak the "rotate" tag into the muxer. Some muxers will catch this properly (like mov), but others (like mkv) can add it as generic tag. Note applications, which use libavformat and assume the old rotate API, will interpret such "rotate" user tags as rotate metadata (which it is not), and incorrectly rotate the video. The ffmpeg/ffplay tools drop the use of the old API for muxing and demuxing, as all muxers/demuxers support the new API. This will mean that the tools will not mistakenly interpret per-track "rotate" user tags as rotate metadata. It will _not_ be treated as regression. Unfortunately, hacks have been added, that allow the user to override rotation by setting metadata explicitly, e.g. via -metadata:s:v:0 rotate=0 See references to trac #4560. fate-filter-meta-4560-rotate0 tests this. It's easier to adjust the hack for supporting it than arguing for its removal, so ffmpeg CLI now explicitly catches this case, and essentially replaces the "rotate" value with a display matrix side data. (It would be easier for both user and implementation to create an explicit option for rotation.) When the code under FF_API_OLD_ROTATE_API is disabled, one FATE reference file has to be updated (because "rotate" is not exported anymore). Tested-by: Michael Niedermayer <michael@niedermayer.cc> Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
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 a mean to alter decoded Audio and Video through chain of 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.
- ffserver is a multimedia streaming server for live broadcasts.
- 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.