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Tags in the Matroska file format can be summarized as follows: There is a level 1-element called Tags containing one or many Tag elements each of which in turn contain a Targets element and one or many SimpleTags. Each SimpleTag roughly corresponds to a single key-value pair similar to an AVDictionaryEntry. The Targets meanwhile contains information to what the metadata contained in the SimpleTags contained in the containing Tag applies (i.e. to the file as a whole or to an individual track). The Matroska muxer writes such metadata. It puts the metadata of every stream into a Tag whose Targets makes it point to the corresponding track. And if the output is seekable, then it also adds another Tag for each track whose Targets corresponds to the track and where it reserves space in a SimpleTag to write the duration at the end of the muxing process into. Yet there is no reason to write two Tag elements for a track and a few bytes (typically 24 bytes per track) can be saved by adding the duration SimpleTag to the other Tag of the same track (if it exists). FATE has been updated because the output files changed. (Tests that write to unseekable output (pipes) needn't be updated (no duration tag has ever been written for them) and the same applies to tests without further metadata.) Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> |
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compat | ||
doc | ||
ffbuild | ||
fftools | ||
libavcodec | ||
libavdevice | ||
libavfilter | ||
libavformat | ||
libavresample | ||
libavutil | ||
libpostproc | ||
libswresample | ||
libswscale | ||
presets | ||
tests | ||
tools | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
.travis.yml | ||
Changelog | ||
configure | ||
CONTRIBUTING.md | ||
COPYING.GPLv2 | ||
COPYING.GPLv3 | ||
COPYING.LGPLv2.1 | ||
COPYING.LGPLv3 | ||
CREDITS | ||
INSTALL.md | ||
LICENSE.md | ||
MAINTAINERS | ||
Makefile | ||
README.md | ||
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 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.
- 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
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.