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Andreas Rheinhardt f249c32eff avcodec/jpeglsenc: Avoid intermediate buffer, allow user-supplied buffers
Up until now, the JPEG-LS encoder allocated a worst-case-sized packet
at the beginning of each encode2 call; then it wrote the packet header
into its destination buffer and encoded the actual packet data;
said data is written into another worst-case-sized buffer, because it
needs to be escaped before being written into the packet buffer.
Finally, because the packet buffer is worst-case-sized, the generic
code copies the actually used part into a fresh buffer.

This commit changes this: Allocating the packet and writing the header
into it is deferred until the actual data has been encoded and its size
is known. This gives a good upper bound for the needed size of the packet
buffer (the upper bound might be 1/15 too large) and so one can avoid the
implicit intermediate buffer and support user-supplied buffers by using
ff_get_encode_buffer().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2021-05-15 11:56:35 +02:00
2021-03-09 02:09:55 +00:00
2019-01-31 10:29:16 -09:00
2019-12-28 11:20:48 +01:00

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 and qt-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.

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