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Lynne 5ca40d6d94 lavu/tx: support in-place FFT transforms This commit adds support for in-place FFT transforms. Since our internal transforms were all in-place anyway, this only changes the permutation on the input. Unfortunately, research papers were of no help here. All focused on dry hardware implementations, where permutes are free, or on software implementations where binary bloat is of no concern so storing dozen times the transforms for each permutation and version is not considered bad practice. Still, for a pure C implementation, it's only around 28% slower than the multi-megabyte FFTW3 in unaligned mode. Unlike a closed permutation like with PFA, split-radix FFT bit-reversals contain multiple NOPs, multiple simple swaps, and a few chained swaps, so regular single-loop single-state permute loops were not possible. Instead, we filter out parts of the input indices which are redundant. This allows for a single branch, and with some clever AVX512 asm, could possibly be SIMD'd without refactoring. The inplace_idx array is guaranteed to never be larger than the revtab array, and in practice only requires around log2(len) entries. The power-of-two MDCTs can be done in-place as well. And it's possible to eliminate a copy in the compound MDCTs too, however it'll be slower than doing them out of place, and we'd need to dirty the input array.		4 years ago
compat	All: update names in copyright headers	4 years ago
doc	lavu/tx: support in-place FFT transforms	4 years ago
ffbuild	ffbuild/common: Make deletion of templates possible	4 years ago
fftools	fftools/ffplay: reindent and some minor cosmetics	4 years ago
libavcodec	avcodec: add Simbiosis IMX video decoder	4 years ago
libavdevice	avdevice/avdevice: Deprecate AVDevice Capabilities API	4 years ago
libavfilter	avfilter/af_afade: remove uneeded '.' from durations in options	4 years ago
libavformat	avformat: add Simbiosis IMX demuxer	4 years ago
libavresample	…
libavutil	lavu/tx: support in-place FFT transforms	4 years ago
libpostproc	lavu/mem: move the DECLARE_ALIGNED macro family to mem_internal on next+1 bump	4 years ago
libswresample	swresample/audioconvert: Fix left shift of negative value	4 years ago
libswscale	swscale/x86/yuv2yuvX: use the movsxdifnidn helper macro	4 years ago
presets	…
tests	tests/checkasm/sw_scale: use memset() to fill dither	4 years ago
tools	tools/target_dec_fuzzer: Adjust threshold for wavpack	4 years ago
.gitattributes	…
.gitignore	tools/python: add script to convert TensorFlow model (.pb) to native model (.model)	5 years ago
.mailmap	mailmap: add entry for myself	4 years ago
.travis.yml	Merge commit '899ee03088d55152a48830df0899887f055da1de'	6 years ago
CONTRIBUTING.md	…
COPYING.GPLv2	…
COPYING.GPLv3	…
COPYING.LGPLv2.1	…
COPYING.LGPLv3	…
CREDITS	…
Changelog	avformat: add Simbiosis IMX demuxer	4 years ago
INSTALL.md	INSTALL.md: Fix Markdown formatting	6 years ago
LICENSE.md	avfilter/vf_geq: Relicense to LGPL	5 years ago
MAINTAINERS	MAINTAINERS: update names	4 years ago
Makefile	tools/enum_options: fix build and add to Makefile	4 years ago
README.md	…
RELEASE	RELEASE: We are after the 4.3 branch point, update for that	5 years ago
configure	avcodec: add initial exr image encoder	4 years ago

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 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.