d4bbc0db01
Both ISOBMFF as well as Matroska require certain OBUs to be stripped before muxing them. There are two functions for this purpose; one writes directly into an AVIOContext, the other returns a freshly allocated buffer with the undesired units stripped away. The latter one actually relies on the former by means of a dynamic buffer. This has several drawbacks: The underlying buffer might have to be reallocated multiple times; the buffer will eventually be overallocated; the data will not be directly copied into the final buffer, but rather first in the write buffer (in chunks of 1024 byte) and then written in these chunks. Moreover, the API for dynamic buffers is defective wrt error checking and as a consequence, the earlier code would indicate a length of -AV_INPUT_BUFFER_PADDING_SIZE on allocation failure, but it would not return an error; there would also be no error in case the arbitrary limit of INT_MAX/2 that is currently imposed on dynamic buffers is hit. This commit changes this: The buffer is now parsed twice, once to get the precise length which will then be allocated; and once to actually write the data. For a 22.7mb/s file with average framesize 113 kB this improved the time for the calls to ff_av1_filter_obus_buf() when writing Matroska from 753662 decicycles to 313319 decicycles (based upon 50 runs a 2048 frames each); for another 1.5mb/s file (with average framesize of 7.3 kB) it improved from 79270 decicycles to 34539 decicycles (based upon 50 runs a 4096 frames). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> Signed-off-by: James Almer <jamrial@gmail.com> |
||
|---|---|---|
| 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
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides a mean to alter decoded Audio and Video through chain of filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements 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,ismindexandqt-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.