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Andreas Rheinhardt e5e5be4c7f avcodec/flac_parser: Fix off-by-one error 
The flac parser uses a fifo to buffer its data. Consequently, when
searching for sync codes of flac packets, one needs to take care of
the possibility of wraparound. This is done by using an optimized start
code search that works on each of the continuous buffers separately and
by explicitly checking whether the last pre-wrap byte and the first
post-wrap byte constitute a valid sync code.

Moreover, the last MAX_FRAME_HEADER_SIZE - 1 bytes ought not to be searched
for (the start of) a sync code because a header that might be found in this
region might not be completely available. These bytes ought to be searched
lateron when more data is available or when flushing.

Unfortunately there was an off-by-one error in the calculation of the
length to search of the post-wrap buffer: It was too large, because the
calculation was based on the amount of bytes available in the fifo from
the last pre-wrap byte onwards. This meant that a header might be
parsed twice (once prematurely and once regularly when more data is
available); it could also mean that an invalid header will be treated as
valid (namely if the length of said invalid header is
MAX_FRAME_HEADER_SIZE and the invalid byte that will be treated as the
last byte of this potential header happens to be the right CRC-8).

Should a header be parsed twice, the second instance will be the best child
of the first instance; the first instance's score will be
FLAC_HEADER_BASE_SCORE - FLAC_HEADER_CHANGED_PENALTY ( = 3) higher than
the second instance's score. So the frame belonging to the first
instance will be output and it will be done as a zero length frame (the
difference of the header's offset and the child's offset). This has
serious consequences when flushing, as returning a zero length buffer
signals to the caller that no more data will be output; consequently the
last frames not yet output will be dropped.

Furthermore, a "sample/frame number mismatch in adjacent frames" warning
got output when returning the zero-length frame belonging to the first
header, because the child's sample/frame number of course didn't match
the expected sample frame/number given its parent.

filter/hdcd-mix.flac from the FATE-suite was affected by this (the last
frame was omitted) which is the reason why several FATE-tests needed to
be updated.

Fixes ticket #5937.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2019-10-07 22:27:18 +02:00
compat compat/cuda: Change inclusion guards 2019-08-05 12:07:09 +02:00
doc doc/formats: Update documentation for chromaprint 2019-10-08 01:15:10 +05:30
ffbuild build: add support for building CUDA files with clang 2019-08-04 19:08:08 +02:00
fftools cmdutils: trailing options may be ignored 2019-10-01 10:43:37 -08:00
libavcodec avcodec/flac_parser: Fix off-by-one error 2019-10-07 22:27:18 +02:00
libavdevice libavdevice: Update the class name as uniform style 2019-08-15 09:29:55 +08:00
libavfilter avcodec/filter: Remove extra '; ' outside of functions 2019-10-07 21:15:55 +02:00
libavformat avformat/flac_picture: Avoid allocation of AVIOContext 2019-10-07 22:27:17 +02:00
libavresample
libavutil avutil/common: Fix underflow for ROUNDED_DIV with unsigned integer 2019-10-06 17:28:29 +08:00
libpostproc Bump minor versions again on master to keep 4.2 versions separate from master 2019-07-21 18:36:31 +02:00
libswresample swresample/audioconvert: fix invalid left shift for 64bit sample format 2019-09-26 16:22:47 +02:00
libswscale swscale: Fix AltiVec/VSX build with recent GCC 2019-10-04 08:58:17 +03:00
presets
tests avcodec/flac_parser: Fix off-by-one error 2019-10-07 22:27:18 +02:00
tools tools/target_dec_fuzzer: Adjust VP7 threshold 2019-09-29 22:18:58 +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 Merge commit '899ee03088d55152a48830df0899887f055da1de' 2019-03-14 15:53:16 -03:00
Changelog avfilter: add anlms filter 2019-10-06 15:09:38 +02:00
configure configure: check for a sufficiently recent enough AMF version 2019-09-09 09:56:12 +02:00
CONTRIBUTING.md
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md INSTALL.md: Fix Markdown formatting 2019-01-31 10:29:16 -09:00
LICENSE.md LICENSE: Add missing libraries that need --enable-version3. 2019-08-12 02:25:39 +02:00
MAINTAINERS MAINTAINERS: add myself to OMX 2019-08-23 17:07:05 -07:00
Makefile tools: Add fuzzer for demuxers 2019-05-31 22:44:30 +02:00
README.md
RELEASE RELEASE: Update value for post 4.2 branch 2019-07-21 18:37:32 +02:00

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

  • 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.