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Lynne af94ab7c7c
lavu/tx: add an RDFT implementation 
RDFTs are full of conventions that vary between implementations.
What I've gone for here is what's most common between
both fftw, avcodec's rdft and what we use, the equivalent of
which is DFT_R2C for forward and IDFT_C2R for inverse. The
other 2 conventions (IDFT_R2C and DFT_C2R) were not used at
all in our code, and their names are also not appropriate.
If there's a use for either, we can easily add a flag which
would just flip the sign on one exptab.

For some unknown reason, possibly to allow reusing FFT's exp tables,
av_rdft's C2R output is 0.5x lower than what it should be to ensure
a proper back-and-forth conversion.
This code outputs its real samples at the correct level, which
matches FFTW's level, and allows the user to change the level
and insert arbitrary multiplies for free by setting the scale option.
2022-01-26 04:12:46 +01:00
compat Replace all occurences of av_mallocz_array() by av_calloc() 2021-09-20 01:03:52 +02:00
doc doc/filters: note format constraint for volumedetect 2022-01-24 09:51:07 +05:30
ffbuild Makefile: Redo duplicating object files in shared builds 2022-01-04 05:01:04 +01:00
fftools fftools/cmdutils: Fix undefined 1 << 31 2022-01-11 00:20:35 +01:00
libavcodec avcodec/h264_parser: don't alter decoder private data 2022-01-24 14:14:24 -03:00
libavdevice avdevice/iec61883: #if unused code away, fix -O0 compilation 2022-01-08 18:15:18 +01:00
libavfilter avfilter/vf_libvmaf: update filter for libvmaf v2.0.0 2022-01-23 11:41:30 -08:00
libavformat avformat/hls: Remove redundant cast 2022-01-21 16:47:38 +01:00
libavutil lavu/tx: add an RDFT implementation 2022-01-26 04:12:46 +01:00
libpostproc lib*/version.h: Bump Versions after release/5.0 branch 2022-01-04 14:29:06 +01:00
libswresample lib*/version.h: Bump Versions after release/5.0 branch 2022-01-04 14:29:06 +01:00
libswscale swscale/x86/swscale: Remove superfluous and invalid ';' 2022-01-22 17:00:45 +01:00
presets
tests tests: add test for ffmpeg's fix_sub_duration feature 2022-01-24 12:57:03 +02:00
tools tools/target_dec_fuzzer: Adjust threshold for prores 2021-12-16 21:06:47 +01:00
.gitattributes fate: add SCC test 2017-01-27 17:06:42 +01:00
.gitignore build: detect Metal.framework and build .metal files 2021-12-18 11:55:47 -08:00
.mailmap mailmap: add entry for myself 2021-03-09 02:09:55 +00:00
.travis.yml Merge commit '899ee03088d55152a48830df0899887f055da1de' 2019-03-14 15:53:16 -03:00
Changelog Changelog: Add new <next> line after 5.0 2022-01-05 08:37:55 -03:00
configure avfilter/vf_libvmaf: update filter for libvmaf v2.0.0 2022-01-23 11:41:30 -08:00
CONTRIBUTING.md Add CONTRIBUTING.md 2016-09-18 10:02:13 +01:00
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md INSTALL.md: Fix Markdown formatting 2019-01-31 10:29:16 -09:00
LICENSE.md avfilter/vf_geq: Relicense to LGPL 2019-12-28 11:20:48 +01:00
MAINTAINERS MAINTAINERS: add my gpg fingerprint 2021-12-23 09:25:16 +08:00
Makefile Makefile: Redo duplicating object files in shared builds 2022-01-04 05:01:04 +01:00
README.md README: fix typo and description of libavfilter 2021-10-08 09:44:34 +05:30
RELEASE Bump Versions before release/4.4 branch 2021-03-20 01:01:12 +01:00

README.md

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 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.