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cbe6ef1031
The only msmpeg4 code that is ever executed by the VC-1 based
decoders is ff_msmpeg4_decode_init() and what is directly
reachable from it. This is:
a) A call to av_image_check_size(), then ff_h263_decode_init(),
b) followed by setting [yc]_dc_scale_table and initializing
scantable/permutations.
c) Afterwards, some static tables are initialized.
d) Finally, slice_height is set.
The replacement for ff_msmpeg4_decode_init() performs a)
just like now; it also sets [yc]_dc_scale_table,
but it only initializes inter_scantable and intra_scantable
and not permutated_intra_[hv]_scantable: The latter are only
used inside decode_mb callbacks which are only called
in ff_h263_decode_frame() which is unused for VC-1.*
The static tables initialized in c) are not used at all by
VC-1 (the ones that are used have been factored out in
previous commits); this avoids touching 327KiB of .bss.
slice_height is also not used by the VC-1 decoder (setting
it in ff_msmpeg4_decode_init() is probably redundant after
b34397b4cd).
*: It follows from this that the VC-1 decoder is not really
based upon the H.263 decoder either; changing this will
be done in a future commit.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.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 means to alter decoded audio and video through a directed graph of connected 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.