[FFmpeg-user] ffmpeg architecture question

Michael Koch astroelectronic at t-online.de
Sun Apr 19 22:31:30 EEST 2020

Am 19.04.2020 um 20:44 schrieb Mark Filipak:
> I'm hooking into this to reply in order to get the message below into 
> the thread.
> But first, I'd like to say that I had no idea this would be 
> controversial. I asked whether ffmpeg traversed filter complexes 
> recursively because that was not happening. Apparently it does 
> recurse, but only if you connect certain pads to certain other pads. 

I don't understand what you mean by "recursively".

> Specifically, it depends on how you 'wire up' a 'blend' filter. I 
> learned that from Michael Koch after he suggested that I reverse the 
> connections to the 'blend' filter. It worked and instead of getting 
> 80% of the input frames in the output, I got 100% of the frames (minus 
> a couple of frames, but that doesn't matter).

I think that's a timestamp problem. The output of the blend filter might 
have the same timestamp as one of its inputs. And then the interleave 
filter gets two frames with the same timestamp and the output becomes 


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