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Clément Bœsch e4a27e2f2d lavc/arm: fix lack of precision in ff_ps_stereo_interpolate_neon
The code originally pre-multiply by 2 the steps, causing the running sum
of the h factors to drift away due to the lack of precision. It quickly
causes an inaccuracy > 0.01.

I tried diverse approaches such as multiply by 2.0 (instead of adding
the value itself) without success.

I'm unable to bench the impact of this change, feel free to compare.

This commit fixes the incoming aacpsdsp tests.

Following is an alternative simplified function (matching the incoming
AArch64 code) that may be used:

function ff_ps_stereo_interpolate_neon, export=1
        vld1.32         {q0}, [r2]
        vld1.32         {q1}, [r3]
        ldr             r12, [sp]
        vmov.f32        q8, q0
        vmov.f32        q9, q1
        vzip.32         q8, q0
        vzip.32         q9, q1
1:
        vld1.32         {d4}, [r0,:64]
        vld1.32         {d6}, [r1,:64]
        vadd.f32        q8, q8, q9
        vadd.f32        q0, q0, q1
        vmov.f32        d5, d4
        vmov.f32        d7, d6
        vmul.f32        q2, q2, q8
        vmla.f32        q2, q3, q0
        vst1.32         {d4}, [r0,:64]!
        vst1.32         {d5}, [r1,:64]!
        subs            r12, r12, #1
        bgt             1b
        bx              lr
endfunc
2017-06-28 11:59:34 +02:00
compat compat/cuda: make cuvidGetDecoderCaps optional 2017-06-01 12:39:06 +02:00
doc dxva: add support for new dxva2 and d3d11 hwaccel APIs 2017-06-27 18:05:02 +02:00
ffbuild build: Allow generating dependencies as a side-effect of assembling 2017-06-21 17:00:29 -03:00
libavcodec lavc/arm: fix lack of precision in ff_ps_stereo_interpolate_neon 2017-06-28 11:59:34 +02:00
libavdevice Use AVOnce as a static variable consistently 2017-05-22 12:36:32 +02:00
libavfilter x86/vf_blend: use ABS2 macro 2017-06-27 20:45:55 -03:00
libavformat Interplay MVE: Implement frame format 0x10 2017-06-27 15:09:12 +02:00
libavresample build: Generalize yasm/nasm-related variable names 2017-06-21 17:00:29 -03:00
libavutil hwcontext_d3d11va: use correct license header 2017-06-28 00:19:55 +02:00
libpostproc Merge commit '92db5083077a8b0f8e1050507671b456fd155125' 2017-05-04 19:59:30 -03:00
libswresample libswresample/swresample: remove obsolete code 2017-06-27 23:21:53 +02:00
libswscale build: Generalize yasm/nasm-related variable names 2017-06-21 17:00:29 -03:00
presets
tests x86/vf_blend: add sse and ssse3 extremity functions 2017-06-27 13:17:23 -03:00
tools build: Generalize yasm/nasm-related variable names 2017-06-21 17:00:29 -03:00
.gitattributes fate: add SCC test 2017-01-27 17:06:42 +01:00
.gitignore build: add support for building .cu files via nvcc 2017-05-15 11:46:50 +02:00
.travis.yml build: Prefer NASM assembler over YASM 2017-06-21 17:00:30 -03:00
CONTRIBUTING.md
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
Changelog dxva: add support for new dxva2 and d3d11 hwaccel APIs 2017-06-27 18:05:02 +02:00
INSTALL.md
LICENSE.md Merge commit '4fef648d10bf3bcfd4b8fa5755c1128966a2427c' 2017-03-15 22:07:47 +01:00
MAINTAINERS MAINTAINERS: Add Manojkumar Bhosale for MIPS, remove myself. 2017-06-08 01:25:15 +02:00
Makefile dxva: add support for new dxva2 and d3d11 hwaccel APIs 2017-06-27 18:05:02 +02:00
README.md
RELEASE Bump minor versions for master after release/3.3 branchpoint 2017-03-31 13:21:06 +02:00
cmdutils.c avformat, ffmpeg: deprecate old rotation API 2017-03-27 13:20:27 +02:00
cmdutils.h Merge commit '122de16dd8108a59a55d30543c9f28b5f61b02d1' 2017-05-05 14:04:30 +02:00
cmdutils_opencl.c cmdutils_opencl: Fix read of uinitialized cl_mem 2017-05-11 13:02:12 +02:00
configure hwcontext_d3d11va: add option to enable debug mode 2017-06-27 18:05:02 +02:00
ffmpeg.c ffmpeg: Flush output BSFs when encode reaches EOF 2017-06-24 15:23:30 +01:00
ffmpeg.h dxva: add support for new dxva2 and d3d11 hwaccel APIs 2017-06-27 18:05:02 +02:00
ffmpeg_cuvid.c ffmpeg_cuvid: adapt for recent filter graph initialization changes 2017-03-03 08:45:43 +01:00
ffmpeg_filter.c ffmpeg: Support setting the hardware device to use when filtering 2017-06-14 22:27:07 +01:00
ffmpeg_hw.c avconv_hw: Free device on initialisation failure 2017-06-18 17:07:25 +01:00
ffmpeg_opt.c dxva: add support for new dxva2 and d3d11 hwaccel APIs 2017-06-27 18:05:02 +02:00
ffmpeg_qsv.c ffmpeg: init filtergraphs only after we have a frame on each input 2017-03-03 08:45:43 +01:00
ffmpeg_videotoolbox.c ffmpeg_videotoolbox: fix usage of av_get_codec_tag_string() 2017-03-29 14:49:29 +02:00
ffplay.c Merge commit '122de16dd8108a59a55d30543c9f28b5f61b02d1' 2017-05-05 14:04:30 +02:00
ffprobe.c ffprobe: Use pixdesc API to provide color space names 2017-06-05 12:18:27 -04:00
ffserver.c Merge commit '122de16dd8108a59a55d30543c9f28b5f61b02d1' 2017-05-05 14:04:30 +02:00
ffserver_config.c ffserver_config: Check for failure to allocate FFServerIPAddressACL 2016-12-22 19:23:08 +01:00
ffserver_config.h ffsrever: Make the status page bitexact if any stream is bitexact 2016-11-29 19:26:26 +01:00

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 and will be ignored.