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FFmpeg git repo
The On2 audio decoder uses huge tables to initialize VLC tables. These tables (mostly) use symbols tables in addition to the codes tables and the lengths tables. This commit makes the codes tables redundant and removes them: If all tables are permuted so that the codes are ordered from left to right in the Huffman tree, the codes become redundant and can be easily calculated at runtime from the lengths (via ff_init_vlc_from_lengths()); this also avoids sorting the codes in ff_init_vlc_sparse()*. The symbols tables are always 16bit, the codes tables are 32bit, 16bit or (rarely) 8bit, the lengths tables are always 8bit. Even though some symbols tables have been used twice (which is no longer possible now because different permutations need to be performed on the code tables sharing the same symbol table in order to order them from left to right), this nevertheless saves about 28KB. *: If the initializations of the VLCs are repeated 2048 times (interleaved with calls to free the VLCs which have not been timed), the number of decicycles spent on each round of initializations improves from 27669656 to 7356159. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> |
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compat | ||
doc | ||
ffbuild | ||
fftools | ||
libavcodec | ||
libavdevice | ||
libavfilter | ||
libavformat | ||
libavresample | ||
libavutil | ||
libpostproc | ||
libswresample | ||
libswscale | ||
presets | ||
tests | ||
tools | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
.travis.yml | ||
Changelog | ||
configure | ||
CONTRIBUTING.md | ||
COPYING.GPLv2 | ||
COPYING.GPLv3 | ||
COPYING.LGPLv2.1 | ||
COPYING.LGPLv3 | ||
CREDITS | ||
INSTALL.md | ||
LICENSE.md | ||
MAINTAINERS | ||
Makefile | ||
README.md | ||
RELEASE |
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 a mean to alter decoded Audio and Video through chain of 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.