mirror of https://git.ffmpeg.org/ffmpeg.git
55fc2c5a89
There is a x86-32 MMXEXT implementation for resampling planar 16bit data. multiple_resample() therefore calls emms_c() if it thinks that this needed. And this is bad: 1. It is a maintenance nightmare because changes to the x86 resample DSP code would necessitate changes to the check whether to call emms_c(). 2. The return value of av_get_cpu_flags() does not tell whether the MMX DSP functions are in use, as they could have been overridden by av_force_cpu_flags(). 3. The MMX DSP functions will never be overridden in case of an x86-32 build with --disable-sse2. In this scenario lots of resampling tests (like swr-resample_exact_lin_async-s16p-8000-48000) fail because the cpuflags indicate that SSE2 is available (presuming that the test is run on a CPU with SSE2). 4. The check includes a call to av_get_cpu_flags(). This is not optimized away for arches other than x86-32. 5. The check takes about as much time as emms_c() itself, making it pointless. This commit therefore removes the check and calls emms_c() unconditionally (it is a no-op for non-x86). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com> |
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| compat | ||
| doc | ||
| ffbuild | ||
| fftools | ||
| libavcodec | ||
| libavdevice | ||
| libavfilter | ||
| libavformat | ||
| libavutil | ||
| libpostproc | ||
| libswresample | ||
| libswscale | ||
| presets | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .travis.yml | ||
| CONTRIBUTING.md | ||
| COPYING.GPLv2 | ||
| COPYING.GPLv3 | ||
| COPYING.LGPLv2.1 | ||
| COPYING.LGPLv3 | ||
| CREDITS | ||
| Changelog | ||
| INSTALL.md | ||
| LICENSE.md | ||
| MAINTAINERS | ||
| Makefile | ||
| README.md | ||
| RELEASE | ||
| configure | ||
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
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides means to alter decoded audio and video through a directed graph of connected filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements 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,ismindexandqt-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.