7cf4c9037c
Both GCC and Clang create code that inlines the loops in next_input() and next_output() at high optimization levels (presumably when there are not too many devices) and this code leads to the creation of .got entries: e7: 48 3b 3d 00 00 00 00 cmp 0x0(%rip),%rdi # ee <av_input_video_device_next+0xe> ea: R_X86_64_REX_GOTPCRELX ff_alsa_demuxer-0x4 ee: 74 43 je 133 <av_input_video_device_next+0x53> f0: 48 3b 3d 00 00 00 00 cmp 0x0(%rip),%rdi # f7 <av_input_video_device_next+0x17> f3: R_X86_64_REX_GOTPCRELX ff_fbdev_demuxer-0x4 f7: 74 41 je 13a <av_input_video_device_next+0x5a> These relocations can't be fixed up lateron when it is known that the symbols exist in the same DSO. This commit therefore marks these symbols as hidden, leading to code like this: f7: 48 8d 05 00 00 00 00 lea 0x0(%rip),%rax # fe <av_input_video_device_next+0xe> fa: R_X86_64_PC32 ff_alsa_demuxer-0x4 fe: 48 39 c7 cmp %rax,%rdi 101: 74 55 je 158 <av_input_video_device_next+0x68> 103: 48 8d 05 00 00 00 00 lea 0x0(%rip),%rax # 10a <av_input_video_device_next+0x1a> 106: R_X86_64_PC32 ff_fbdev_demuxer-0x4 10a: 48 39 c7 cmp %rax,%rdi 10d: 74 50 je 15f <av_input_video_device_next+0x6f> (Note: It is actually strange that the compiler creates code that tries to read the addresses from the .got given that the addresses can be read directly from indev_list/outdev_list.) 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.