2f710734c8
Up until now, ff_write_chained() copied the packet (manually, not with av_packet_move_ref()) from a packet given to it to a stack packet whose timing and stream_index is then modified before being sent to another muxer via av_(interleaved_)write_frame(). Afterwards it is intended to sync the fields of the packet relevant to freeing again; yet this only encompasses buf, side_data and side_data_elems and not the newly added opaque_ref. The other fields are not synced so that the returned packet can have a size > 0 and data != NULL despite its buf being NULL (this always happens in the interleaved codepath; before commit fe251f77c80b0512ab8907902e1dbed3f4fe1aad it could also happen in the noninterleaved one). This leads to double-frees if the interleaved codepath is used and opaque_ref is set. This commit therefore changes this by directly reusing the packet instead of a spare packet. Given that av_write_frame() does not change the packet given to it, one only needs to restore the timing information to return it as it was; for the interleaved codepath it is not possible to do likewise*, because av_interleaved_write_frame() takes ownership of the packets given to it and returns blank packets. But precisely because of this users of the interleaved codepath have no legitimate expectation that their packet will be returned unchanged. In line with av_interleaved_write_frame() ff_write_chained() therefore returns blank packets when using the interleaved codepath. Making the only user of said codepath compatible with this was trivial. *: Unless one wanted to create a full new reference. Reviewed-by: Lynne <dev@lynne.ee> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
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.
- 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.