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FFmpeg git repo
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Andreas Rheinhardt 97610e856a avcodec/dcahuff: Combine tables, use ff_init_vlc_from_lengths() 
Up until now, initializing the dca VLC tables uses ff_init_vlc_sparse()
with length tables of type uint8_t and code tables of type uint16_t
(except for the LBR tables, which uses length and symbols of type
uint8_t; these tables are interleaved). In case of the quant index
codebooks these arrays were accessed via tables of pointers to the
individual tables.

This commit changes this: First, we switch to ff_init_vlc_from_lengths()
to replace the uint16_t code tables by uint8_t symbol tables
(this necessitates ordering the tables from left-to-right in the tree
first). These symbol tables are interleaved with the length tables.

Furthermore, these tables are combined in order to remove the table of
pointers to individual tables, thereby avoiding relocations (for x64
elf systems this amounts to 96*24B = 2304B saved in .rela.dyn) and
saving 1280B from .data.rel.ro (for 64bit systems). Meanwhile the
savings in .rodata amount to 2709 + 2 * 334 = 3377B. Due to padding
the actual savings are higher: The ELF x64 ABI requires objects >= 16B
to be padded to 16B and lots of the tables have 2^n + 1 elements
of these were from replacing uint16_t codes with uint8_t symbols;
the rest was due to the fact that combining the tables eliminated
padding (the ELF x64 ABI requires objects >= 16B to be padded to 16B
and lots of the tables have 2^n + 1 elements)). Taking this into
account gives savings of 4548B. (GCC by default uses an even higher
alignment (controlled by -malign-data); for it the savings are 5748B.)

These changes also necessitated to modify the init code for
the encoder tables.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-09-16 18:07:29 +02:00
compat compat/cuda: switch from powf to __powf intrinsic 2022-09-03 20:27:34 +02:00
doc avformat: add LAF demuxer 2022-09-16 10:02:19 +02:00
ffbuild
fftools fftools/ffplay: fix rotation incorrect when frame contains the displaymatrix 2022-09-15 16:16:16 +08:00
libavcodec avcodec/dcahuff: Combine tables, use ff_init_vlc_from_lengths() 2022-09-16 18:07:29 +02:00
libavdevice avutil/internal: Move avpriv-file API to a header of its own 2022-09-03 15:41:44 +02:00
libavfilter avfilter/vf_colorspace_cuda: mark fall-through 2022-09-15 19:35:30 +02:00
libavformat avformat/ape: fix overflow in total_blocks 2022-09-16 18:04:20 +02:00
libavutil lavu/riscv: fix off-by-one in bit-magnitude clip 2022-09-15 18:11:12 -03:00
libpostproc configure: always enable gnu_windres if available 2022-08-13 14:42:36 +02:00
libswresample swsresample/swresample: error out on invalid layouts 2022-09-14 09:52:33 -03:00
libswscale swscale/la: Add output_lasx.c file. 2022-09-10 22:56:39 +02:00
presets
tests fate/spdif: Add spdif tests 2022-09-13 14:50:01 +02:00
tools tools/target_dec_fuzzer: Adjust threshold for UTVIDEO 2022-09-10 17:32:47 +02:00
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Changelog avformat: add LAF demuxer 2022-09-16 10:02:19 +02:00
configure libavfilter: add vf_colorrange_cuda, CUDA-accelerated color conversion filter 2022-09-13 22:59:30 +02:00
CONTRIBUTING.md
COPYING.GPLv2
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INSTALL.md
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MAINTAINERS MAINTAINERS: Add ED25519 key for signing my commits in the future 2022-08-09 21:57:31 +02:00
Makefile Makefile: Prompt for reconfigure on lavc/hwaccels.h modification 2022-07-01 00:34:38 +02:00
README.md
RELEASE RELEASE: update after 5.1 branch 2022-07-13 00:31:42 +02:00

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 means to alter decoded audio and video through a directed graph of connected 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.