d0bd00c8eb
When the Ogg muxer writes a page, it has to do three things: It needs to write a page header, then it has to actually copy the page data and then it has to calculate and write a CRC checksum of both header as well as data at a certain position in the page header. To do this, the muxer used a dynamic buffer for both writing as well as calculating the checksum via an AVIOContext's feature to automatically calculate checksums on the data it writes. This entails an allocation of an AVIOContext, of the opaque specific to dynamic buffers and of the buffer itself (which may be reallocated multiple times) as well as memcopying the data (first into the AVIOContext's small write buffer, then into the dynamic buffer's big buffer). This commit changes this: The page header is no longer written into a dynamic buffer any more; instead the (small) page header is written into a small buffer on the stack. The CRC is then calculated directly via av_crc() on both the page header as well as the page data. Then both the page header and the page data are written. Finally, ogg_write_page() can now no longer fail, so it has been modified to return nothing; this also fixed a bug in the only caller of this function: It didn't check the return value. 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.