[FFmpeg-devel] [PATCH] Limited timecode support for lavd/decklink

Marton Balint cus at passwd.hu
Fri Jun 1 00:29:21 EEST 2018

On Thu, 31 May 2018, Jonathan Morley wrote:

> Thank you for the clarification, Dave. It might be that the Blackmagic 
> approach to collecting timecode doesn’t work for that one source because 
> it is in the horizontal space (HANC) instead of the vertical (VANC). I 
> am not sure. Sadly I don’t think my solution is all encompassing, but it 
> does seem to help in enough cases I would like to get it integrated with 
> master.
> I am still a bit thrown about the initial “Unable to set timecode” 
> error, but believe it to be initialization related. I will wait to hear 
> back from Marton on my overall approach and see what I can do to clean 
> that up.

av_dict_set returns < 0 on error, so the condition seems wrong.

> As for the other error message my plan is to demote that to a debug.

That is a good idea.

On the other hand, I believe the usefulness of this is in its current form 
is still very limited, because typically the first few frames are NoSignal 
frames, how the end user supposed to know which frame is the one with the 
first valid timecode?

I'd rather see a new AVPacketSideData type which will contain the timecode 
as a string, so you can set it frame-by-frame.


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