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Andreas Rheinhardt ac322ec214 avutil/cpu_internal: Fix check for SSE2SLOW
For SSE2 and SSE3, there are four states that the two flags
involved (AV_CPU_FLAG_SSE[23] and AV_CPU_FLAG_SSE[23]SLOW) can convey.
When ordered from worst to best they are:
1. both flags unset (SSE[23] unavailable)
2. the slow flag set, the ordinary flag unset (this is designed
for cases where SSE2 is available, but so slow that MMX(EXT)/SSE
code is usually faster)
3. both flags set (SSE2 is available, but there might be scenarios
where MMX(EXT)/SSE code is faster)
4. the ordinary flag set, the slow flag unset (this is the normal case)

The ordinary macros for checking cpuflags return true
in the latter two cases; the fast macros only return true for
the latter case. Yet the macros to check for slow currently
only return true in case three.

This seems unintended. In fact, the only uses of the slow macros
are all of the form
if (EXTERNAL_SSE2(cpu_flags) || EXTERNAL_SSE2_SLOW(cpu_flags))
where the check for EXTERNAL_SSE2_SLOW is completely redundant.
Even more importantly, it is not what was intended. Before
6369ba3c9c, the checks passed
in cases 2 to 4. Said commit changed this to something that
only passes for the third case. Commits
7fb758cd8e and
c1913064e3 restored the old behaviour,
yet merging 4efab89332 (in commit
ac774cfa57) broke this again
by changing it to what it is now.*

This commit changes the macros to make the slow macros check
whether a specific instruction is supported, even if slow.
This restores the intended meaning to all uses of the SLOW macros
and is generally more natural.

*: Libav only checks for EXTERNAL_SSE2_SLOW, i.e. for the third case
only.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-06-18 19:25:03 +02:00
compat Replace all occurences of av_mallocz_array() by av_calloc() 2021-09-20 01:03:52 +02:00
doc avdevice/pulse_audio_dec: deprecate frame_size option 2022-06-16 21:28:20 +02:00
ffbuild ffbuild/common: Fix CPPFLAGS applied for compiling C++ files 2022-05-24 21:30:52 +02:00
fftools ffprobe: add -o option 2022-06-13 22:42:55 +02:00
libavcodec avcodec/vlc: Use structure instead of VLC_TYPE array as VLC element 2022-06-17 16:47:29 +02:00
libavdevice avdevice/pulse_audio_dec: deprecate frame_size option 2022-06-16 21:28:20 +02:00
libavfilter avfilter/vf_zscale: dissallow too small slices 2022-06-16 10:23:30 +02:00
libavformat avformat/librist: bump required version to 0.2.7 2022-06-18 16:32:23 +02:00
libavutil avutil/cpu_internal: Fix check for SSE2SLOW 2022-06-18 19:25:03 +02:00
libpostproc lib*/version: Move library version functions into files of their own 2022-05-10 06:49:32 +02:00
libswresample swresample/noise_shaping_data: Remove unused tables 2022-06-15 04:58:14 +02:00
libswscale all: Replace if (ARCH_FOO) checks by #if ARCH_FOO 2022-06-15 04:56:37 +02:00
presets
tests avutil/tests/uuid: add uuid tests 2022-06-12 18:34:37 +10:00
tools tools/target_dec_fuzzer: add a custom get_buffer2() implementation 2022-06-06 09:40:44 -03:00
.gitattributes fate: add SCC test 2017-01-27 17:06:42 +01:00
.gitignore gitignore: add config_components.h 2022-03-17 18:35:41 -03:00
.mailmap mailmap: add entry for myself 2021-03-09 02:09:55 +00:00
.travis.yml Merge commit '899ee03088' 2019-03-14 15:53:16 -03:00
Changelog avfilter: add virtualbass filter 2022-06-16 10:23:30 +02:00
configure avformat/librist: bump required version to 0.2.7 2022-06-18 16:32:23 +02:00
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 myself as maintainer for LoongArch. 2022-06-08 18:29:30 +02:00
Makefile Makefile: avoid cp-ing over existing executable files 2022-06-01 19:38:50 -05:00
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

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.