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From SMPTE RDD 5-2006, the grain seed is to be computed from the following definition of `pic_offset`: > When decoding H.264 | MPEG-4 AVC bitstreams, pic_offset is defined as > follows: > - pic_offset = PicOrderCnt(CurrPic) + (PicOrderCnt_offset << 5) > where: > - PicOrderCnt(CurrPic) is the picture order count of the current frame, > which shall be derived from [the video stream]. > > - PicOrderCnt_offset is set to idr_pic_id on IDR frames. idr_pic_id > shall be read from the slice header of [the video stream]. On non-IDR I > frames, PicOrderCnt_offset is set to 0. A frame shall be classified as I > frame when all its slices are I slices, which may be optionally > designated by setting primary_pic_type to 0 in the access delimiter NAL > unit. Otherwise, PicOrderCnt_offset it not changed. PicOrderCnt_offset is > updated in decoding order. Co-authored-by: James Almer <jamrial@gmail.com> Signed-off-by: Niklas Haas <git@haasn.dev> Signed-off-by: James Almer <jamrial@gmail.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 a mean to alter decoded Audio and Video through chain of 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.