MiniATEM - inverting colours

[Stuart91]

I've got a small installation that's using a BlackMagic MiniATEM switcher. The setup is relatively simple, there is a PC going into input one, and three cameras in 2-4.

 

If the PC is connected straight into the input (just a direct HDMI cable) then it looks fine.

 

The challenge is that the PC signal needs split beforehand, so it can feed a projector in the room as well as the webcast. With the HDMI split in place, the projector looks fine, but the colours on the ATEM look inverted - the light blue of a typical Windows background is a garish green. The problem appears on the USB stream as well as on the HDMI output of the ATEM.

 

Confusingly, if I set the ATEM HDMI output to be "Input one direct", the colours look fine. But that's a bit cumbersome for normal use - the operators just want to be able to bash buttons on the switcher rather than using the computer.

 

I'm guessing that it's some kind of EDID confusion introduced by the HDMI splitter. I've tried two different models of splitter (albeit both cheap Amazon efforts) with the same result from both. Different computers produce the same problem, so it's not anything specific to the customer's PC.

 

BlackMagic support have suggested moving the PC into a different input, which I haven't had the chance to check yet but is the top of my list. I've also got a Lindy HDMI matrix sitting which has some options for how EDID is passed so will try that too.

 

 

Are there any other possibilities that I should be looking at?

[Dave m]

There is something about the atem input 1 that's different you the others, but I can't remember what it is. Maybe colourspace? Is the cheap splitter at the projector end? Or the atem end ?

EDIT input one is YUV only

Edited September 27, 2020 by Dave m

[Stuart91]

Thanks, Dave.

 

BlackMagic support said Input 1 was a "super input" but couldn't explain what made it different, apart from the way it can be used to determine the output signal format if that's set to auto mode.

 

The YUV thing makes sense - I've seen some mention of that in other threads about the Mini. It certainly looks like some sort of colour mismatch - if we were in the (old, familiar) analog world I'd have been looking for dead pins on a VGA lead.

 

The HDMI splitter sits after the PC, one output goes to the ATEM, the other into an older Kramer scaler which feeds the projector.

 

The problem persists even with nothing plugged into the other output of the splitter, so I don't think the Kramer is sending anything that confuses the source.

[abbotsmike]

I would assume in that case that the Splitter is sending an EDID that makes the PC run in RGB colour space. I'd try an alternative DA/Splitter.

 

Or does the PC have a second monitor output that could be used?

[Stuart91]

I would assume in that case that the Splitter is sending an EDID that makes the PC run in RGB colour space. I'd try an alternative DA/Splitter.

 

Thanks, that makes sense. I've got a Lindy HDMI Matrix which has some EDID management options - I'll try it and see if it can make the problem go away.

 

Unfortunately, it's about the same price as the ATEM, so a pretty expensive sticking plaster!

 

Or does the PC have a second monitor output that could be used?

 

The graphics card has VGA, DVI, and HDMI outputs, I think it can drive two at once. At the moment the VGA is the "local" monitor, swapping over onto the DVI (using an adaptor) gave me the same problem. I suppose that shouldn't be surprising, since DVI doesn't seem to support YUV colour space.

[Stuart91]

I managed to get back onsite today, and swapping the PC from Input 1 to Input 4 eliminated the problem. Nice to have a simple fix for once!

 

I suspect the more proper solution is to use splitters that handle EDID a bit more intelligently.

[GaryNattrass]

I thought that input one could be used to define the sync and other default settings so using it for a PC or Mac would not be a good choice?

 

Just about to the the mini pro iso so look forward to playing with it.

Edited September 30, 2020 by GaryNattrass

[Dave m]

The atem is quite impressive- especially for the money.I started with Shibaden and National (Panasonic) mixers- genlock etc.

I also have the atem television studio HD but it's bloody fussy about resolutions.

I have bought a streamdeck to allow use of macros via companion. Also-" here to record " offer a title software that's chroma key based. I guess you could run PowerPoint with a green background. There is a development using a rasberry Pi to emulate a hyperdeck so it can be triggered by macros

[Stuart91]

I thought that input one could be used to define the sync and other default settings so using it for a PC or Mac would not be a good choice?

 

The way I understand it is that with the output set to "auto" whatever is plugged into input one sets the output. So if you plug a 1080i50 camera into input one, the output switches to 1080p50. In the control software you can fix the output. Otherwise there's the possibility that the output will glitch every time input 1 gets re-plugged.

 

I'm not sure what happens with sync etc. The ATEM apparently works throughout with YUV colour space only, so my issue was probably caused by the splitter not carrying EDID from the ATEM to the computer correctly, the computer outputs RGB, and the ATEM displays it as YUV.

 

I agree with Dave - the ATEM is very impressive for the price, but there are quite a few minor gotchas, which mean that if you're doing anything out of the ordinary with it you can hit problems.

 

Two challenges I've found (apart from the PC colour issue):

There's no way of doing a Multiview whilst also having the Program output available via HDMI

The Key on/off button can only be used to activate the Upstream key, not the Downstream Key. That wouldn't be a problem apart from the fact that the DSK has a much more limited feature set, no Chroma for example.

[Dave m]

https://www.cinegearpro.co.uk/products/seetec-atem156-15-6-live-streaming-broadcast-director-monitor-with-4-hdmi-quad-split-display-for-atem-mini-video-switcher-mixer

Bit of a faff- plus £500. But it does free up the output to record. However you'd lose the actual display on the pro/iso for streaming.

[timsabre]

I have recently been very impressed by a setup using Vmix software plus some £15 hdmi-usb capture dongles from Amazon. Does everything the atem mini pro does, but with more flexibility.

[GaryNattrass]

Stuart91

 

 

Does input 1 also set the conversion for inputs 2-4 so if you put a laptop running at a weird rate it will try to re-sync nputs 2-4 to match it?

[Stuart91]

I have recently been very impressed by a setup using Vmix software plus some £15 hdmi-usb capture dongles from Amazon. Does everything the atem mini pro does, but with more flexibility.

 

I'd tend to agree - we've got another customer that's chosen to go down this route and they seem to be getting along very well. (They used a BlackMagic 4-input PCI card for the capture though)

 

I suspect some people will prefer to have the physical controls of the Mini, but the lack of flexibility is very annoying.

 

Out of interest, which dongles is it that you're using?

 

Does input 1 also set the conversion for inputs 2-4 so if you put a laptop running at a weird rate it will try to re-sync nputs 2-4 to match it?

 

I'm not sure, it'll be an interesting thing to try at some point.

 

The specs seem to claim that every input can be scaled/converted to whichever output format you choose, but I've no idea what "suggestions" will be offered via EDID.

 

One strange things that we did get was the camera connected to Input 1 comes up with almost a "split screen" effect, there are two versions of the image squashed up and stacked above each other. Unplugging and replugging the HDMI seemed to fix it. I'm not sure if that'll happen every time, or if it was just related to the other faffing that I'd been doing.

[timsabre]

I have recently been very impressed by a setup using Vmix software plus some £15 hdmi-usb capture dongles from Amazon. Does everything the atem mini pro does, but with more flexibility.

 

I'd tend to agree - we've got another customer that's chosen to go down this route and they seem to be getting along very well. (They used a BlackMagic 4-input PCI card for the capture though)

 

I suspect some people will prefer to have the physical controls of the Mini, but the lack of flexibility is very annoying.

 

Out of interest, which dongles is it that you're using?

These ones, (or the many identical versions):

https://www.amazon.co.uk/Elikliv-Capture-Streaming-Broadcast-Recording/dp/B08CK8PZ4H

The only problem is finding the right mix of USB sockets so you don't max out the bandwidth of the USB bus. Also they all appear identically called "USB Video" so knowing which is which takes a bit of experimentation.The Blackmagic quad card would be a much better solution but it's £400.

Edited October 1, 2020 by timsabre

[abbotsmike]

Having used vmix and cheap capture devices extensively, they often drop frames left right and centre, and sometimes just give up entirely until you reboot them.

 

Then the poor laptop running it all overheats, and someone wonders why their livestream went down.

 

Lots of solutions for lots of budgets, but there's usually a reason that cheap stuff is cheap! (I use blackmagic extensively also)