[FFmpeg-user] Audio delayed with DeckLink

PSPunch shima at pspunch.com
Fri Oct 14 07:42:09 EEST 2016

Hi Marton,

The suggested options fixed the sync issue in a snap.
Thank you, thank you, thank you!!

BTW, I understand from brief searching that the wallclock option is 
relatively new. Just curious how FFmpeg users dealt with Decklink boards 
until they were available??

David Shimamoto

On 2016/10/14 6:00, Marton Balint wrote:
> I tested the DeckLink drivers on Linux, and they very often fail to
> provide proper timestamps for the audio and video they produce, there is
> also a noticable clock skew after a few hours if you use their video
> clock, and they also skip frames (different number of audio and video
> frames) in the event of a signal loss.
> To work around this problem, there are the audio_pts and video_pts
> options, so you can customize where you want your timestamps to come
> from. In my experience, wallclock is the only thing that works reliably,
> so I typically use these options:
> -vsync 1
> -video_pts wallclock
> -audio_pts wallclock
> -af aresample=async=1

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