1d9aac9c4b
Decoders that might use quarter pixel motion estimation (namely MPEG-4 as well as the VC-1 family) currently use MpegEncContext.me.qpel_(put|avg) as scratch space for pointers to arrays of function pointers. (MotionEstContext contains such pointers as it supports quarter pixel motion estimation.) The MotionEstContext is unused apart from this for the decoding part of mpegvideo. Using the context at all is for decoding is actually unnecessary and easily avoided: All codecs with quarter pixels set me.qpel_avg to qdsp.avg_qpel_pixels_tab, so one can just unconditionally use this in ff_mpv_reconstruct_mb(). MPEG-4 sets qpel_put to qdsp.put_qpel_pixels_tab or to qdsp.put_no_rnd_qpel_pixels_tab based upon whether the current frame is a b-frame with no_rounding or not, while the VC-1-based decoders set it to qdsp.put_qpel_pixels_tab unconditionally. Given that no_rounding is always zero for VC-1, using the same check for VC-1 as well as for MPEG-4 would work. Since ff_mpv_reconstruct_mb() already has exactly the right check (for hpeldsp), it can simply be reused. (This change will result in ff_mpv_motion() receiving a pointer to an array of NULL function pointers instead of a NULL pointer for codecs without qpeldsp (like MPEG-1/2). It doesn't matter.) 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 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.