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![]() Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers. |
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compat | ||
doc | ||
libavcodec | ||
libavdevice | ||
libavfilter | ||
libavformat | ||
libavresample | ||
libavutil | ||
libswscale | ||
presets | ||
tests | ||
tools | ||
.gitattributes | ||
.gitignore | ||
.travis.yml | ||
arch.mak | ||
avconv_dxva2.c | ||
avconv_filter.c | ||
avconv_opt.c | ||
avconv_qsv.c | ||
avconv_vda.c | ||
avconv_vdpau.c | ||
avconv.c | ||
avconv.h | ||
avplay.c | ||
avprobe.c | ||
Changelog | ||
cmdutils_common_opts.h | ||
cmdutils.c | ||
cmdutils.h | ||
common.mak | ||
configure | ||
COPYING.GPLv2 | ||
COPYING.GPLv3 | ||
COPYING.LGPLv2.1 | ||
COPYING.LGPLv3 | ||
CREDITS | ||
INSTALL | ||
library.mak | ||
LICENSE | ||
Makefile | ||
README | ||
README.md | ||
RELEASE | ||
version.sh |
Libav
Libav 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.libavresample
implements audio mixing and resampling routines.libswscale
implements color conversion and scaling routines.
Tools
- avconv is a command line toolbox to manipulate, convert and stream multimedia content.
- avplay is a minimalistic multimedia player.
- avprobe is a simple analisys tool to inspect multimedia content.
- 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
Conding examples are available in the doc/example directory.
License
Libav codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.