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5120305137
The Matroska (and WebM) file format achieves forward-compability by insisting that demuxers ignore and skip elements they don't know about. Unfortunately, this complicates the detection of errors as errors resulting from loosing sync can't be reliably distinguished from unknown elements that are part of a future version of the standard. Up until now, the strategy to deal with this situation was to skip all unknown elements that are not obviously erroneous; if an error happened, it was tried to seek to the last known good position to resync from (and resync to level 1 elements). This is working fine if the input is seekable, but if it is not, then the skipped data can usually not be rechecked lateron. This is particularly acute if unknown-length clusters are in use, as the check for whether a child element exceeds the containing master element is ineffective in this situation. To remedy this, a new heuristic has been introduced: If an unknown element is encountered in non-seekable mode, an error is presumed to have happened based upon a combination of the length of the row of the already encountered unknown elements and of how far away skipping this element would take us. 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 | ||
.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.