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Andreas Rheinhardt 27f40b1dcd avformat/matroskadec: Don't abort resyncing upon seek failure
When an error happens, the Matroska demuxer tries to resync to level 1
elements from an earlier position onwards. If the seek to said earlier
position fails, the demuxer currently treats this as an unrecoverable
error. And that behaviour is suboptimal as said failure is nothing
unrecoverable or unexpected (when the input isn't seekable).
It is preferable to simply resync from the earliest position available
(i.e. the start of the AVIOContext's buffer) onwards if the seek failed.

Here are some scenarios that might be treated as unrecoverable errors
by the current code if the input isn't seekable. They all have in
common that the current position is so far away from the desired
position that the seek can't be fulfilled from the AVIOContext's buffer:

1. Blocks (both SimpleBlocks as well as a Block in a BlockGroup) for
which reading them as binary EBML elements succeeds, but whose parsing
triggers an error (e.g. an invalid TrackNumber). In this case the
earlier position from which resyncing begins is at the start of the block
(or even earlier).
2. BlockGroups, whose parsing fails in one of the latter elements. Just
as in 1., the start of the BlockGroup (the target of the seek) might be
so far away from the current position that it is no longer in the
buffer.
3. At the beginning of parsing a cluster, the cluster is parsed until a
SimpleBlock or a BlockGroup is encountered. So if the input is damaged
between the beginning of the cluster and the first occurrence of a
SimpleBlock/BlockGroup and if said damage makes the demuxer read/skip so
much data that the beginning of the cluster is no longer in the buffer,
demuxing will currently fail completely.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2019-07-16 16:16:57 -03:00
compat compat/cuda/ptx2c: don't drop final newline 2019-05-24 19:23:39 +02:00
doc doc/codecs: Add missing documentation for nointra 2019-07-15 09:21:33 +08:00
ffbuild
fftools ffmpeg_opt: Respect default disposition when select audio/video 2019-07-03 10:33:44 +08:00
libavcodec avcodec: remove reference to AVPacket's destruct field 2019-07-15 11:20:03 -03:00
libavdevice lavd/avfoundation: Set correct default value 0 for option capture_raw_data. 2019-07-08 20:02:41 +02:00
libavfilter avfilter/vf_hysteresis: use time_base from framesync 2019-07-14 19:14:10 +02:00
libavformat avformat/matroskadec: Don't abort resyncing upon seek failure 2019-07-16 16:16:57 -03:00
libavresample
libavutil avutil/hwcontext_vaapi: move kernel_driver into CONFIG_LIBDRM 2019-07-11 09:34:57 +08:00
libpostproc
libswresample swresample/swresample: check for invalid sample rates 2019-05-26 14:43:32 +02:00
libswscale swscale/tests/swscale: Lengthen pixfmt name buffer to 21 bytes 2019-05-13 13:39:49 +02:00
presets
tests fate: add hls fmp4 segment type test case 2019-07-15 21:57:43 +08:00
tools tools/target_dec_fuzzer: Remove redundant av_free() 2019-07-13 14:42:57 +02:00
.gitattributes
.gitignore tools/python: add script to convert TensorFlow model (.pb) to native model (.model) 2019-07-01 10:23:47 -03:00
.travis.yml
Changelog avformat/movenc: use unspecified language by default 2019-07-12 20:26:38 +02:00
configure avutil/mips: optimize UNPCK&SAD macros with MSA2.0 instruction. 2019-07-10 12:54:57 +02:00
CONTRIBUTING.md
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md
LICENSE.md LICENSE: Clarify --enable-nonfree. 2019-05-10 01:18:58 +02:00
MAINTAINERS
Makefile tools: Add fuzzer for demuxers 2019-05-31 22:44:30 +02:00
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

  • 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 a mean to alter decoded Audio and Video through chain of 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.