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Ganesh Ajjanagadde c8780822ba swresample/resample: speed up build_filter for Blackman-Nuttall filter This uses the trigonometric double and triple angle formulae to avoid repeated (expensive) evaluation of libc's cos(). Sample benchmark (x86-64, Haswell, GNU/Linux) test: fate-swr-resample-dblp-44100-2626 old: 1104466600 decicycles in build_filter(loop 1000), 256 runs, 0 skips 1096765286 decicycles in build_filter(loop 1000), 512 runs, 0 skips 1070479590 decicycles in build_filter(loop 1000), 1024 runs, 0 skips new: 588861423 decicycles in build_filter(loop 1000), 256 runs, 0 skips 591262754 decicycles in build_filter(loop 1000), 512 runs, 0 skips 577355145 decicycles in build_filter(loop 1000), 1024 runs, 0 skips This results in small differences with the old expression: difference (worst case on [0, 2*M_PI]), argmax 0.008: max diff (relative): 0.000000000000157289807188 blackman_old(0.008): 0.000363951585488813192382 blackman_new(0.008): 0.000363951585488755946507 These are judged to be insignificant for the performance gain. PSNR to reference file is unchanged up to second decimal point for instance. Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>		9 years ago
compat	Merge commit '407ac22322e5ce67996ec54ef619cafa4c9ceb78'	9 years ago
doc	avformat: add acm demuxer	9 years ago
libavcodec	avcodec/mpeg12dec: Do not call show_bits() with invalid bits	9 years ago
libavdevice	gdigrab: grab right desktop size if DPI in use, based on patch from Alexander Brotzge	9 years ago
libavfilter	avfilter/showcqt: remove yuv offset	9 years ago
libavformat	mpegtsenc: Implement writing of Opus trim_start/trim_end control values	9 years ago
libavresample	avresample/resample: remove unused variable	10 years ago
libavutil	libavutil/channel_layout: Check strtol*() for failure	9 years ago
libpostproc	…
libswresample	swresample/resample: speed up build_filter for Blackman-Nuttall filter	9 years ago
libswscale	swscale: rename sws_rgb2rgb_init to ff_sws_rgb2rgb_init	9 years ago
presets	…
tests	fate: update fate-source ref file	9 years ago
tools	Replace remaining occurances of av_free_packet with av_packet_unref	9 years ago
.gitattributes	…
.gitignore	gitignore: ignore object file temporaries	9 years ago
.travis.yml	…
COPYING.GPLv2	…
COPYING.GPLv3	…
COPYING.LGPLv2.1	…
COPYING.LGPLv3	…
CREDITS	…
Changelog	avformat: add acm demuxer	9 years ago
INSTALL.md	…
LICENSE.md	…
MAINTAINERS	MAINTAINERS: add key fingerprint	9 years ago
Makefile	Merge commit 'fb472e1a11a4e0caed2c3c91da01ea8e35d9e3f8'	9 years ago
README.md	…
RELEASE	…
arch.mak	…
cmdutils.c	all: use FFDIFFSIGN to resolve possible undefined behavior in comparators	9 years ago
cmdutils.h	…
cmdutils_common_opts.h	…
cmdutils_opencl.c	all: use FFDIFFSIGN to resolve possible undefined behavior in comparators	9 years ago
common.mak	Merge commit 'c1aac39eaccd32dc3b74ccfcce701d3d888fbc6b'	9 years ago
configure	Merge commit 'a0562e531723923b632684c7b51a9dd584bf534f'	9 years ago
ffmpeg.c	all: use FFDIFFSIGN to resolve possible undefined behavior in comparators	9 years ago
ffmpeg.h	ffmpeg: add abort_on option to allow aborting on empty output	9 years ago
ffmpeg_dxva2.c	…
ffmpeg_filter.c	ffmpeg_filter: check encoder before using it to set frame size.	9 years ago
ffmpeg_opt.c	all: remove some casts of function pointer to void *	9 years ago
ffmpeg_qsv.c	Merge commit 'fb472e1a11a4e0caed2c3c91da01ea8e35d9e3f8'	9 years ago
ffmpeg_vdpau.c	…
ffmpeg_videotoolbox.c	ffmpeg/videotoolbox: protect UTGetOSTypeFromString on both VDA and VT	9 years ago
ffplay.c	Replace remaining occurances of av_free_packet with av_packet_unref	9 years ago
ffprobe.c	ffprobe: add support for printing packet strings metadata as packet tags	9 years ago
ffserver.c	Replace remaining occurances of av_free_packet with av_packet_unref	9 years ago
ffserver_config.c	ffserver_config: check for INT_MIN before doing FFABS	9 years ago
ffserver_config.h	…
library.mak	…
version.sh	version.sh: add note that ffversion.h is auto-generated	9 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.
ffserver is a multimedia streaming server for live broadcasts.
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. Few developers follow pull requests so they will likely be ignored.