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The ff_avg_pixels{4,8,16}_l2_mmxext() functions are only ever
used in the last step (the one that actually writes to the dst buffer)
where the number of lines to process is always equal to the
dimensions of the block, whereas ff_put_pixels{8,16}_mmxext()
are also used in intermediate calculations where the number of
lines can be 9 or 17.
The code in qpel.asm uses common macros for both and processes
more than one line per loop iteration; it therefore checks
for whether the number of lines is odd and treats this line separately;
yet this special handling is only needed for the put functions,
not the avg functions. It has therefore been %if'ed away for these.
The check is also not needed for ff_put_pixels4_l2_mmxext() which
is only used by H.264 which always processes four lines. Because
ff_{avg,put}_pixels4_l2_mmxext() processes four lines in a single loop
iteration, not only the odd-height handling, but the whole loop
could be removed.
Reviewed-by: James Almer <jamrial@gmail.com>
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.