[FFmpeg-user] issues with SDI output to Dektec cards

[Carl Zwanzig]

On 7/3/2024 9:11 AM, Izhar Marinov wrote:
> Has anyone had any experience with SDI output to Dektec device?
> 
> It seems to be working initially but the output delay to the SDI grows
> by a few seconds per minute, eventually the circular buffer fills up.

I had a similar problem with BMD Decklink cards (on windoze), but 
haven't tried it in the last couple of years and didn't spent much time 
looking for the cause; the output was fine using other software.


Just guessing here- if frames are being decoded at non-drop-frame rate 
but they're being pulled out of the buffer at the drop-frame rate, you'd 
  have some apparent delay and eventually run out of space. That 
wouldn't necessarily account for multiple seconds delay per minute, only 
a frame or so per minute. (Or decoding at 30fps and outputing at 25.)

Perhaps forcing the decode and output rates might help. I don't know 
about the Dektec boards, but the BMDs are a bit sensitive to the rate 
settings.

z!