Yeah, so I’ve noticed that sometimes my key & fill go out of sync. Haven’t been able to pinpoint what exactly causes this. I’m using a decklink 8k pro set up as 4 separate devices and server 2.3.3. Config looks like this:
Any ideas? Is it a caspar thing or a decklink thing? Should I be using a single device for key&fill to ensure sync? I’d like to have one key&fill pair and two discrete outputs and with the 8k decklink card that’s only possible when it’s configured as 4 devices afaik.
I never configured an 8K card myself. But I am told, that it works the same as the Duo 2.
So actually you should be able to configure one channel as a fill & key in the control panel applet and leave two as using a single BNC each. Set device 1 keyer mode to external, get rid of the key-device line and move the device number of the two remaining channels as being 2 and 3 (instead of 3 and 4). That should do the trick.
Hi Sarksim, didikunz is right, you need to go to “Desktop Video” and configure 1+3, 2+4, don’t bother if is in&out.
Then in the config file just leave only one of the two channels but with external keyer.
Here my config:
I have both pro4k and 8k and doesnt managed to make it work like duo 2 Two scenarios working fill+key x2 or 4 fill. I tried only output mode. I speak for HD channels If you want 4k two sceanarios, 4k at BNC 1 or 4HD sync at 4 BNC
Pro4k is the previous model that replaced by pro8k I mean there are two ways to get 4k One from BNC at position 1 and the other to connect 4 BNC at outputs and combine a 4k signal through 4HD (like quad but synchro)
You’d think so, but no. With the 8k pro for some reason you can only configure 1, 2 or 4 devices to the card in desktop video app. I found some posts on the blackmagic forums and it looks like this was an issue already back in 2019.
I used to have the card configured like @Andrea mentioned, but that means I only get f&k + one output.
@didikunz Yep, it’s possible to have 2ch f+k, I can confirm that, it works fine. I only used at 1080i50 because I don’t have any 4k equipment at the moment.
@sarksim I forgot to mention, because it’s not really a solution, that you can use 4 channel and then put in sync fill-key.
You have to play with the buffer length,
it has the effect to delay the channel itself.
Of course is more a workaround than a solution, and also I just tried for few minutes so I don’t know if could change between reboot or if is stable and reliable.
Thanks, but I don’t think that would solve the problem since key&fill are not always out of sync, in fact most of the time everything works ok. I contacted Blackmagic support to see if they can come up with a solution.
I think if you dont need 4k channel the best solution is DUO 2 you can do all the channels whatever you want and cheaper.
I believe is something with DesktopVideo software , when I bought my first pro4K I noticed that I can send 4K only with use of 4 BNC outputs and send the 1/4 of video and create the 4K output.
After 2-3 days with a newer DesktopVideo version I managed to send full 4k only from BNC number 1
But still there are only two configurations with pro4k or pro8k , 2 FILL+ KEY OR 4 FILL
Blackmagic support confirmed that it isn’t currently possible to mix dual-link and single link devices on a 8K Pro, but they didn’t say if it would be possible at some point in the future. They also said I should use a reference signal to sync the outputs, which is what I’m going to do.
Did you ever test resolutions higher than 1080P? Seems like the Decklink 8K Pro hardware supports 2x key + fill on 4k 60 4:2:2.
I would like to send two 4k 60 HTML5 transparant overlays into an BMD ATEM 4 M/E Constellation 4K, (vMix does appear to support this with the Decklink 8K Pro hardware though i’m anwaiting awnser from their support team to comfirm this).
@didikunz On the official wiki the Decklink 8K Pro is not supported on " Server: Supported Video Hardware" but from this conversation it appears that it is supported?
Another noob question you might be of help with, is key + fill the only way to acchive 4k transparanty on 12g SDI? New BMD 12g ATEM hardware appears to also support an alpha channel wich would make key + fill unnecessary?
Really? The SDK docs say that the 8K is the one card that doesn’t need an external sync when recreating the K+F pairing in software.
This is something I have been looking at recently, as part of custom resolutions and getting multiple outputs in sync.
The implementation of external_separate_device is relying on there not being any drift in clocks, and for no frames to be dropped/skipped/repeated.
The SDK and these newer cards (8k pro, quad2, duo2) have some new functionality that allows for this kind of use case of pairing outputs and running them with a single clock which should avoid these drift issues.
Hopefully at some point this external_separate_device can be replaced with a better sync mode that will allow for grouping outputs to keep them in sync which will also solve the sync issues I was seeing with custom resolutions.
vMix support just came back with the following regarding the Decklink 8K Pro.
Unfortunately, the Decklink 8K Pro is configured a little differently internally than other Decklink cards and in our testing did not behave as expected for Key + Fill Output and so we do not recommend it for that and why it is not listed in our documentation for Key + Fill support
This concludes that in vMix the DeckLink 4K Extreme 12G is the only card that can output 4k 60 key + fill (1 channel) the Decklink 8K Pro is not supported.
This brings us back to my original question, is CasparCG/ Decklink 8K Pro capable of outputting 2 channels key + fill 2160 60hz (on a single Decklink card
I have a DeckLink 8k Pro fully functional, double channel fill+key for me the trick was in the blackmagic settings: 1ºin+2ºout and 3ºin+4ºout in this way the f+k are linked together and perfectly in sync
I tried only in 1080@50i, I don’t have any way to test higher resolution at the moment
That might help with your sync issues?
Seems like no one has tried @Andrea’s working config file for two key and fills in 2160p/i5000
This is exavly what i would like to do, but i do not have the 8k card yet.