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Vignesh Venkatasubramanian 2a3640de84 avformat/movenc: Support alpha channel for AVIF
AVIF specification allows for alpha channel as an auxiliary item (in
case of still images) or as an auxiliary track (in case of animated
images).  Add support for both of these. The AVIF muxer will take
exactly two streams (when alpha is present) as input (first one being
the YUV planes and the second one being the alpha plane).

The input has to come from two different images (one of it color and
the other one being alpha), or it can come from a single file
source with the alpha channel extracted using the "alphaextract"
filter.

Example using alphaextract:
ffmpeg -i rgba.png -filter_complex "[0:v]alphaextract[a]" -map 0 -map "[a]" -still-picture 1 avif_with_alpha.avif

Example using two sources (first source can be in any pixel format and
the second source has to be in monochrome grey pixel format):
ffmpeg -i color.avif -i grey.avif -map 0 -map 1 -c copy avif_with_alpha.avif

The generated files pass the compliance checks in Compliance Warden:
https://github.com/gpac/ComplianceWarden

libavif (the reference avif library) is able to decode the files
generated using this patch.

They also play back properly (with transparent background) in:
1) Chrome
2) Firefox (only still AVIF, no animation support)

Reviewed-by: James Zern <jzern@google.com>
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
2022-06-27 13:46:33 -03:00
compat compat/w32dlfcn.h: Remove MAX_PATH limit and replace LoadLibraryExA with LoadLibraryExW 2022-06-21 13:27:46 +03:00
doc libavcodec/qsvenc: Enable fixed QP configure in qsv CQP runtime 2022-06-27 12:09:44 +08:00
ffbuild ffbuild/common: Fix CPPFLAGS applied for compiling C++ files 2022-05-24 21:30:52 +02:00
fftools fftools/ffplay: fix YUV conversion mode 2022-06-27 12:17:59 +02:00
libavcodec avcodec/libx265: make X265 CSP selection pixel format independent 2022-06-27 09:25:22 +03:00
libavdevice avdevice/oss_dec: account for sample size when computing timestamp 2022-06-19 23:01:20 +02:00
libavfilter avfilter/Makefile: always make colorspace.o 2022-06-25 17:55:53 +05:30
libavformat avformat/movenc: Support alpha channel for AVIF 2022-06-27 13:46:33 -03:00
libavutil avutil/ppc/cpu: Use proper header for OpenBSD PPC CPU detection 2022-06-25 12:16:51 +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 swscale/x86/swscale: Simplify macro 2022-06-22 13:36:18 +02:00
presets
tests avformat/matroskaenc: Split updating CodecPrivate from writing it 2022-06-24 18:33:18 +02:00
tools tools/target_dec_fuzzer: add a custom get_buffer2() implementation 2022-06-06 09:40:44 -03:00
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.gitignore gitignore: add config_components.h 2022-03-17 18:35:41 -03:00
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Changelog AV1 VDPAU hwaccel Decode support 2022-06-25 09:05:58 +08:00
configure AV1 VDPAU hwaccel Decode support 2022-06-25 09:05:58 +08:00
CONTRIBUTING.md
COPYING.GPLv2
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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

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.