Ganesh Ajjanagadde
e9c7493f19
avfilter/vsrc_mandelbrot: avoid sqrt for epsilon calculation
This rewrites into a similar expression avoiding sqrt. Similarity is assured since sqrt(x^2 + y^2)/(x+y) lies in [1/sqrt(2), 1] for x, y > 0. Tested on x86-64, Haswell, GNU/Linux. Command: ffmpeg -f lavfi -i mandelbrot -f null - old (draw_mandelbrot): 277625266 decicycles in draw_mandelbrot, 256 runs, 0 skips 304527322 decicycles in draw_mandelbrot, 512 runs, 0 skips 377593582 decicycles in draw_mandelbrot, 1024 runs, 0 skips 338539499 decicycles in draw_mandelbrot, 2048 runs, 0 skips 583630357 decicycles in draw_mandelbrot, 4096 runs, 0 skips new (draw_mandelbrot): 274635709 decicycles in draw_mandelbrot, 256 runs, 0 skips 300287046 decicycles in draw_mandelbrot, 512 runs, 0 skips 371819935 decicycles in draw_mandelbrot, 1024 runs, 0 skips 336663765 decicycles in draw_mandelbrot, 2048 runs, 0 skips 581851016 decicycles in draw_mandelbrot, 4096 runs, 0 skips Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
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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
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. Few developers
follow pull requests so they will likely be ignored.
Description
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