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It is unnecessary, as we already have the entries sorted by probability and therefore implicitly by length. All we need on top of that to build the tree is the number of entries of a given length. Doing so gives a 3.6% speedup of ff_mjpeg_encode_huffman_close() here; it also saves about 640B of .text here. The new code puts values with higher probability to the left of the tree. The old code did not and therefore the FATE checksums needed to be updated. Due to MJPEG's 0xFF unescaping file sizes as well as file checksums needed to be updated; the decoded picture hashes stayed the same. Given that codes on the left of the tree have on average fewer bits set than codes on the right, the file sizes mostly improve (all except vsynth3-mjpeg-444). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
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FFmpeg README
FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodec
provides implementation of a wider range of codecs.libavformat
implements streaming protocols, container formats and basic I/O access.libavutil
includes hashers, decompressors and miscellaneous utility functions.libavfilter
provides means to alter decoded audio and video through a directed graph of connected filters.libavdevice
provides an abstraction to access capture and playback devices.libswresample
implements audio mixing and resampling routines.libswscale
implements 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
,ismindex
andqt-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.
Languages
C
90.1%
Assembly
7.9%
Makefile
1.3%
C++
0.2%
Objective-C
0.2%
Other
0.1%