No description
a1ae66c827
DVDs naturally consist of segmented MPEG-PS blobs within a VOB (i.e. VOBs are not linear). NAV packs set the segment boundaries. When switching between segments, discontinuities occur and thus the subdemuxer needs to be reset. The current approach to manage this is by invoking ff_read_frame_flush() on the subdemuxer context, via a callback function which is invoked during the menu or dvdnav block functions. The same subdemuxer context is used throughout the demux, with a stretched PTS wrap bits value (64) + disabled overflow correction, and then flushed on each segment. Eventually, a play_end context variable is set to declare EOF. However, this approach causes frame drops. The block read flushes the demuxer before the frame read is complete, causing frames to drop on discontinuity. The play_end signal likewise ends playback before the frame read is complete, causing frames to drop at end of the title. To compound the issue, the PTS wrap bits value of 64 is wrong; the VOBU limit is actually 32 and the overflow correction should work. Instead, EOF the MPEG-PS subdemuxer organically when each VOB segment ends, and re-open it if needed with the offset after the full frame read is complete. In doing so, correct the PTS wrap behavior to 32 bits and remove the play_end/segment_started signals and callback pattern. Note that the timestamps as reported by the NAV packets are known as "PTMs", so the fields storing the time prior to adjustment are renamed accordingly. This makes it more clear when we are offsetting the NAV packet reported timestamps versus what we present as a demuxer. Signed-off-by: Marth64 <marth64@proxyid.net> |
||
|---|---|---|
| compat | ||
| doc | ||
| ffbuild | ||
| fftools | ||
| libavcodec | ||
| libavdevice | ||
| libavfilter | ||
| libavformat | ||
| libavutil | ||
| libpostproc | ||
| libswresample | ||
| libswscale | ||
| presets | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| Changelog | ||
| configure | ||
| CONTRIBUTING.md | ||
| COPYING.GPLv2 | ||
| COPYING.GPLv3 | ||
| COPYING.LGPLv2.1 | ||
| COPYING.LGPLv3 | ||
| CREDITS | ||
| INSTALL.md | ||
| LICENSE.md | ||
| MAINTAINERS | ||
| Makefile | ||
| README.md | ||
| RELEASE | ||
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.