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Andreas Rheinhardt 5ac9d78dd2 avcodec/atrac9dec: Make tables used to initialize VLCs smaller The ATRAC9 decoder uses VLCs which are currently initialized with static length tables of type uint8_t and code tables of type uint16_t. Furthermore, in one case the actually desired symbols are in the range -16..15 and in order to achieve this an ad-hoc symbols table of type int16_t is calculated. This commit modifies this process by replacing the codes tables by symbols tables and switching to ff_init_vlc_from_lengths(); the signed symbols are stored in the table after having been shifted by 16 to fit into an uint8_t and are shifted back when the VLC is created. This makes all symbols fit into an uint8_t, saving space. Furthermore, the earlier tables had holes in them (entries with length zero that were inserted because the actually used symbols were not contiguous); these holes are unnecessary in the new approach, leading to further saving. Finally, given that now both lengths as well as symbols are of the same type, they can be combined; this saves a pointer for each VLC. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>		2020-12-08 17:51:46 +01:00
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libavcodec	avcodec/atrac9dec: Make tables used to initialize VLCs smaller	2020-12-08 17:51:46 +01:00
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configure	avcodec/mss4: Don't duplicate standard JPEG tables	2020-12-08 17:51:46 +01:00

README.md

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.