[LAD] Library for accurate time stamping using a DLL

Olivier Guilyardi ml at xung.org
Tue Feb 3 13:30:40 UTC 2009

Paul Davis wrote:
> On Tue, 2009-01-27 at 13:49 +0100, Olivier Guilyardi wrote:
>> For example, in FFmpeg, each audio and video packets are tagged using a PTS
>> which is computed using av_gettime() which calls gettimeofday().
> this should be considered a bug and reported as such to the FFmpeg group
> (preferably with a patch to make it use clock_gettime() if available).
> gettimeofday is a non-linear, non-mononotic clock if ntp is used. it is
> not suitable for timestamping in this way. without ntp, it will work
> better, but it is still subject to potential non-monotonicity.

I just wanted to let you know that an interesting discussion is going on the
ffmpeg-devel mailing list, about choosing a time source, NTP effects, and A/V
synchronization. It is named "libavdevice: PTS stability and risks of drift".


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