5e3b7bd56d
When the Matroska muxer writes the Cues (the index), it groups index entries with the same timestamp into the same CuePoint to save space. But given Matroska's variable-length length fields, it either needs to have an upper bound of the final size of the CuePoint before writing it or the CuePoint has to be assembled in a different buffer, so that after having assembled the CuePoint (when the real size is known), the CuePoint's header can be written and its data copied after it. The first of these approaches is the currently used one. This entails finding out the number of entries in a CuePoint before starting the CuePoint and therefore means that the list is read at least twice. Furthermore, a worst-case upper-bound for the length of a single entry was used, so that sometimes bytes are wasted on length fields. This commit switches to the second approach. This is no longer more expensive than the current approach if one only resets the dynamic buffer used to write the CuePoint's content instead of opening a new buffer for every CuePoint: Writing the trailer of a file with 540.000 CuePoints improved actually from 219054414 decicycles to 2164379394 decicycles (based upon 50 iterations). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
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.