Solved: dropped Frames with Blackmagic Decklink UltraStudio 4k Mini

[frankfunk]

I can't get smooth output on my UltraStudio. Both the SDI and HDMI outputs drop around 60% of frames.

Recording shows repeated frames, mostly 2, sometimes 3 in a row:

1 1 3 3 5 5 5 8 8 9 9 etc.

Tested several machines: Mac Mini M1, MacBook Pro M1, Mac Studio M1.

Output with other software (Mitti) via UltraStudio is smooth!
Output via HDMI Out from Resolume is smooth!
Only Resolume & UltraStudio won't play nicely together.

I've tested both generative Footage (45° Lines are great to identify stuttery playback) as well as QT ProRes and DXV footage in different framerates (25/50/60).

[cosmowe]

I can confirm that. Same here on Pc.

Setting the composition to Auto instead of 50 or 60 Hz lowers the drops.....but not completely.


Best wishes
cosmowe

[frankfunk]

Thanks for the confirmation. This really sucks, and there's no solution? Is there other similar hardware that can give me SDI Key & Fill output with frame-sync and without dropped frames?

[cosmowe]

Setting the composition to Auto instead of 50 or 60 Hz lowers the drops.....but not completely.

Can you also confirm that?


....I would guess that a BM Decklink I/O Card would do the trick.......

[Bassindaniel]

Add an 1ms delay on your screen output in advanced window.

[frankfunk]

@Bassindaniel: Ok, wow, that completely fixed it. How did I not know that? Thank you so much, this saves my complete workflow!

@cosmowe: Yes, I can confirm that with fps set to Auto there's jitter - see below

These are my findings while outputting 1080p50 with external key on my UltraStudio 4k Mini to a Hyperdeck through a 2 M/E Constellation:

Code: Select all

SETTING           RESULT
DELAY   FPS       FRAME DROPS   JITTER
0 ms    Auto      1/2           high 
1 ms    Auto      0		high
0 ms    50        1/3           none
1 ms    50        0             none

So while the 1 ms delay fixes the dropped frames, the jitter (meaning the variance in the time interval between frames) is fixed by setting the composition fps correctly.

Thanks so much guys, this has helped me tremendously and will hopefully help others, too.