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Andreas Rheinhardt 71753c5235 avcodec/on2avc: Use smaller tables for VLCs
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>
2020-12-08 17:51:44 +01:00
compat avfilter/scale_cuda: add lanczos algorithm 2020-11-04 01:43:21 +01:00
doc hlsenc: expand hls_fmp4_init_filename with strftime() 2020-12-08 21:02:23 +08:00
ffbuild ffbuild: Refine MIPS handling 2020-07-23 16:30:02 +02:00
fftools fftools/ffprobe: add support for HDR10+ metadata 2020-12-05 19:20:11 -03:00
libavcodec avcodec/on2avc: Use smaller tables for VLCs 2020-12-08 17:51:44 +01:00
libavdevice avdevice/decklink: remove the duplicated warning message 2020-12-05 09:00:53 +08:00
libavfilter avfilter/aeval: add timeline support for aeval 2020-12-08 15:34:14 +01:00
libavformat hlsenc: expand hls_fmp4_init_filename with strftime() 2020-12-08 21:02:23 +08:00
libavresample
libavutil hwcontext_vulkan: wait and signal semaphores when transferring to CUDA 2020-12-05 23:53:23 +01:00
libpostproc Bump minor versions after branching 4.3 2020-06-08 22:49:04 +02:00
libswresample swresample/audioconvert: Fix left shift of negative value 2020-09-30 10:50:45 +02:00
libswscale lsws/x86/yuv2rgb: Fix compilation with mmxext or ssse3 disabled. 2020-11-14 15:37:57 +01:00
presets
tests avfilter/af_earwax: fix filter behavior 2020-12-07 21:09:08 +01:00
tools tools/target_bsf_fuzzer: set bitstream filter options 2020-11-20 19:20:33 -03:00
.gitattributes
.gitignore tools/python: add script to convert TensorFlow model (.pb) to native model (.model) 2019-07-01 10:23:47 -03:00
.mailmap mailmap: add entry for myself 2020-07-13 11:24:04 +08:00
.travis.yml
Changelog avformat/mspdec: Microsoft Paint (MSP) demuxer 2020-12-06 20:03:47 +11:00
configure avcodec/dxva2: add AV1 decode support 2020-11-12 15:55:16 +01:00
CONTRIBUTING.md
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md
LICENSE.md avfilter/vf_geq: Relicense to LGPL 2019-12-28 11:20:48 +01:00
MAINTAINERS avformat: add amv muxer 2020-11-09 14:58:38 +10:00
Makefile tools/enum_options: fix build and add to Makefile 2020-11-20 15:20:24 +01:00
README.md
RELEASE RELEASE: We are after the 4.3 branch point, update for that 2020-06-10 00:20:24 +02:00

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 and qt-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.