mirror of https://git.ffmpeg.org/ffmpeg.git
78db8405c0
Many of the routines within hevcdsp_epel_neon and hevcdsp_qpel_neon store temporary buffers on the stack. When consuming it, many of these functions use the stack pointer as incremental pointer for reading the data (instead of storing it in another register), which is rather unusual. Technically, this is fine as long as the pointer remains properly aligned. However in the case of ff_hevc_put_hevc_qpel_uni_w_hv64_8_neon_i8mm, after incrementing sp when reading data (within each 16 pixel wide stripe) it would then reset the stack pointer back to a lower value, for reading the next 16 pixel wide stripe, expecting the data to remain untouched. This can't be assumed; data on the stack below the stack pointer can be clobbered (e.g. by a signal handler). Some OS ABIs allow for a little margin that won't be touched, aka a red zone, but not all do. The ones that do, guarantee 16 or 128 bytes, not 9 KB. Convert this function to use a separate pointer register to iterate through the data, retaining the stack pointer to point at the bottom of the data we require to remain untouched. Signed-off-by: Martin Storsjö <martin@martin.st> |
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| compat | ||
| doc | ||
| ffbuild | ||
| fftools | ||
| libavcodec | ||
| libavdevice | ||
| libavfilter | ||
| libavformat | ||
| libavutil | ||
| libpostproc | ||
| libswresample | ||
| libswscale | ||
| presets | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .travis.yml | ||
| CONTRIBUTING.md | ||
| COPYING.GPLv2 | ||
| COPYING.GPLv3 | ||
| COPYING.LGPLv2.1 | ||
| COPYING.LGPLv3 | ||
| CREDITS | ||
| Changelog | ||
| INSTALL.md | ||
| LICENSE.md | ||
| MAINTAINERS | ||
| Makefile | ||
| README.md | ||
| RELEASE | ||
| configure | ||
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
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.