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Andreas Rheinhardt
6e5dbd6268
avformat/smacker: Improve timestamps
A Smacker file can contain up to seven audio tracks. Up until now, the pts for the i. audio packet contained in a Smacker frame was simply the end timestamp of the last i. audio packet contained in an earlier Smacker frame. The problem with this is that a Smacker stream need not contain data in every Smacker frame and so the current i. audio packet present may come from a different underlying stream than the last i. audio packet contained in an earlier frame. The sample hypnotix.smk* exhibits this. It has three audio tracks and the first of the three has a longer first packet, so that the audio for the first track is contained in only 235 packets contained in the first 235 Smacker frames; the end timestamp of this track is 166696 (about 7.56s at a timebase of 1/22050); the other two audio tracks both have 253 packets contained in the first 253 Smacker frames. Up until now, the 236th packet of the second track being the first audio packet in the 236th Smacker frame would get the end timestamp of the last first audio packet from the last Smacker frame containing a first audio packet and said last audio packet is the first audio packet from the 235th Smacker frame from the first audio track, so that the timestamp is 166696. In contrast, the 236th packet from the third track (whose packets contain the same number of samples as the packets from the second track) has a timestamp of 156116 (because its timestamp is derived from the end timestamp of the 235th packet of the second audio track). In the end, the second track ended up being 177360/22050 s = 8.044s long; in contrast, the third track was 166780/22050 s = 7.56s long which also coincided with the video. This commit fixes this by not using timestamps from other tracks for a packet's pts. *: https://samples.ffmpeg.org/game-formats/smacker/wetlands/hypnotix.smk Reviewed-by: Timotej Lazar <timotej.lazar@araneo.si> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
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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
andqt-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.
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