[FFmpeg-devel] [PATCH] avdevice/decklink: adjust for timecode lag

[Gyan]

On 28-07-2019 01:37 AM, Marton Balint wrote:
>
>
> On Fri, 26 Jul 2019, Gyan wrote:
>
>>
>> Patch supported by and tested at Google.
>
> Seems like a huge hack for a decklink issue... ;)
>
> I wonder if there are better approaches to work around this. Like 
> dropping all frames until we have a valid signal.

Let's say the scenario is like this,

Frame #            TC                 Status
      1                   no               dropped
      2                   no               demuxed
      3                   no               demuxed
      4                   no               dropped
      5          04:11:21:04       dropped
      6          04:11:21:05       demuxed


We don't want to drop frames before 6; they still should be digitized 
(sometimes the TC appears after ~15 frames). But the stored TC needs to 
be 04:11:21:04 + (2 - 5) =  04:11:21:01

> How is this repoducible? do you have an exact model / signal type / TC 
> source requirement?

Usually RP188 but tested over various configurations afaik, but my 
contact at Google has the details. I'll ask them to post.

Gyan