-
Signifcant Grading Latency On the Video Out Monitor
Hi all,
We are experiencing significant latency / sluggishness whilst grading
shots. I know playback synch issues between the timeline and the
monitor are well documented, but I have not seen any discussion on the
delay between the modifying the grade and it appearing on the monitor
on this forum.The latency ranges between 100ms and 400ms. The latency occurs whilst
using the tangent wave as well as and the UI. I have tested and ruled
out any latency between the tangent and the davinci via shortening the cable and
also by virtue of the fact that I can see latency when modifying the
grade in the UI.You can also think of it in terms of seeing the image stutter through grading changes whilst
sliding the gain control up slowly. Or seeing the delay between the UI
viewer and the monitor when resetting a primary grade on a shot.We are running 1080P at 25FPS and have set the video out to 8bit
which makes it better, as documented, but the latency still exists at the 100ms – 400ms
range. Also ensuring that dual link is switched off in the decklink prefs also help as documented.The latency gets worse with many complex nodes as you would expect but is
still present on grades with only one empty node. It also gets significantly worse when many shots are grouped.The latency is present on all media types we’ve used including UC QTs, ProRes, DPX and R3ds.
The other interesting thing is that the latency is reduced to almost passable levels when switching the video out to 720P, a piece of evidence rather worrying as it suggests that the latency must be between the GPU and the decklink card, and is probably unfixable by beefing up the machine or by adding the BM control panel.
Anyways,
My questions are:
1. Is anyone NOT experiencing said latency on the mac resolve?
2. Will adding extra GPU cores reduce the latency for grades with only one node?
3. Is there anything we can do, ie better machine, to get the latency down?
Thanks!
Marcus.
Setup:
Mac Pro 8 Core Intel Xeon 2.93 GHz
Decklink Extreme 3d+
Video Cards: NVIDEO Geforce GT120 (UI) + NVIDEO Geforce GTX 285(GPU)
Tangent Wave Panel -
22 Replies
-
Which slots are your cards installed in the Mac Pro ?
What version of Resolve are you running ?
Which driver version of the Decklink card ?
Which driver version of CUDA ?
-chrispy
-
I saw this when I mistakenly updated the Decklink drivers with non resolve drivers – i.e. the ones that get installed when you install resolve
Robbie Carman
—————-
Colorist and Author
Check out my new Books:
Video Made on a Mac
Apple Pro Training Series DVDSP
From Still To Motion -
I realize this issue is probably not related to the recent OS update interfering with the FX4000, but is there a possible corollary? https://forums.creativecow.net/thread/277/4939
jPo
You mean “Old Ben”? Ben Kenobi?
-
It looks like no cuda. or full res debayer if red is the source
-
which are the “Resolve Drivers” one should use then?
i have latency issues aswell (even before my GTX wasn´t recognized anymore 😉cheerz
mark -
when you install resolve those are the correct drivers for the deckling card, not the ones you get of the BM website. Currently there isn’t version parity as the Resolve drivers let you do things like output timecode to scopes etc. I made the mistake early on when I saw that the deckling drivers had been updated going to the BM website and installing them, next thing you know resolve was very sluggish and had problems like you describe. The fix was to uninstall the non-resolve drivers, uninstall resolve and then reinstall resolve and all was right with the world again.
Robbie Carman
—————-
Colorist and Author
Check out my new Books:
Video Made on a Mac
Apple Pro Training Series DVDSP
From Still To Motion -
Hi Christopher,
Which slots are your cards installed in the Mac Pro ?
GT120 PCIe Slot-2
GTX 285 PCIe Slot-1
Decklink Slot-3What version of Resolve are you running ?
7.1.1Which driver version of the Decklink card ?
7.9.2Which driver version of CUDA ?
3.2.17 -
Hey Robbie, Chris JP et al,
Thanks for responding!
So are you all saying that you have no noticeable latency whilst grading QTs in 1080? I’m assuming you are running 30fps?
For example, when you change the gain of a shot, whether it be on the UI or a tangent, the video out monitor jumps to attention. There is no lag at all.
Cheers,
Marcus.
-
Hi Marcus,
The best latency is seen when using the SDI monitoring path.
Are you using SDI or HDMI? Do you have any devices between the Decklink and the monitoring device?
Rohit
-
Hi,
We are monitoring via sdi through a black magic sdi router which doesn’t introduce any latency as far a I know.
Thanks,
Marcus
Reply to this Discussion! Login or Sign Up