Ok, this maybe a somewhat stupid question, but I am looking for some parameters on configuration of system to use for a vMix system. To be honest, I haven't done much more than play around with vmix - so the answers to these questions might be obvious to someone who has experience with it, but these are the breaks...

The most important goal for me is stability. I need something to be 100% rock-stable. Spending a few $$$ extra for that stability isn't a big issue. Also, at this point (at least until multi-channel recording is supported), my plan is to use the system JUST as a video mixer - so no recording at all (I will handle that out-board).

So, let's just get to it.

I am looking to handle 4 HD-SDI inputs (so I am planning 2 BMD DeckLink 3D Extreme cards - the ones with dual inputs on them). I would then want to use an HD-SDI output (at least, for the moment) - so I will plan to add another BMD card (probably another 3D extreme - just to be consistent). I will need to "play" some video files, and will have quite a number of overlay graphics (i.e. lower 3rd's title - etc). I will be making a LOT of use of the color correction capabilities (so, assume that this will be active on all 4 inputs).

Here are my high-level questions:

1. What is the most important criteria? Is it CPU or graphics card? For example, would there be any benefit in building a dual-cpu system (i.e. workstation-class) instead of simply a very-fast single chip box? I am, honestly, thinking of using either the Corei7 980x, or some of the new server-class chips (the 5600 series).

2. If graphics are critically important, then should I be leaning toward the Nvidia boards or the ATI boards? Anything specific to consider here? (for example, I am really planning to use two monitors - one for the "operator" and one for a local program output, if possible).

3. What size of monitor makes sense for the operator? Or, in other words, does the system support multiple displays (i.e. the ability to use dual monitors - one for the operator and one for preview only)? If not, is this likely to be supported in the future (today, I run 2 displays for the video operator - one that has just preview - and one that has just program out - but, since a hardware mixer is in place today, there is no need to interact beyond the on-screen display).

Just looking for some recommendations before jumping into this - I would really hate to spend $$$ on a rig, and then find out that it isn't going to be enough - or that the next version is going to triple the requirements.

Also - one final question - is there any tally support in the system? We aren't running one today - but the users would just LOVE to have this functionality).

Jeff :-)

Interesting... so the graphics card is the key.... curious...

On the graphics card, then, you prefer (or can use) the Nvidia stuff (not complaining - just asking) (i.e. CUDA), or is this just a general "I prefer NVidia"? Is SLI of benefit here?

I suppose I am REALLY trying to understand the load involved here.

Now, I know that this may be asking a "sensitive question" - but what about the future? I would plan to use this rig for at least a few years - so I want to make sure that I am able to handle anything you are cooking up. So, any plans for OpenCL (or some other form of graphics offloading)? If so, any idea of what you think would be good?


BTW - I am fairly impressed that you can handle something this complex without getting CPU limited. I admire your coding skillz to do this. I (briefly) looked that the CutFour package - and they seemed to be VERY CPU limited. So, sounds impressive.

As to the tally, here is what I know (and I do not claim to be the uber-expert here):

Most tally systems (at least the ones that I am familiar with) usually interface with the mixer via GPIB (or serial) connection. The lights themselves are really nothing more than LED's that are directly powered from the interface cable. I will say this, we have been looking heavily at the DataVideo products (www.datavideo.us) and their tally system basically uses a 5-pin XLR connector that runs from a break-out box that is attached to their mixer via a GPIB interface cable. There are some "broadcast-grade" tally systems that use other interfaces - but most "just pro" grade systems are nothing more than relays connected to the mixer.

I would tend to think that, for yours, a simple USB connected relay-trigger would be adequate. Honestly, I am not the uber-USB guy - so I don't know if there is some HID type standard for this - but, honestly, whatever you wanted to use would be fine. I would envision a box with a USB port on one end, and a whole bunch (probably 32 or more) relay outputs (nothing super powerful - usually a simple 12v relay would be more than adequate).

I DO know that tally systems are usually mixer specific - there isn't some type of "standard" available. Even in the broadcast space, the vast majority are separated (meaning that the light is one element - and it is usually just hardwired to a relay interface unit that is specific to the mixer. The mixer company makes (or recommends) a tally interface - and then you just wire up (either with XLR or 1/4 connectors) to whatever tally you want to use. There are some very high-end systems out there (where they, for example, can flash the camera #) - but I don't know much about them.

The tally is then connected to the mixer preview and program outputs. If the operator, for example, selects camera 3 as the "next" (or preview) source, then one light is turned on. Then, when the operator transitions camera 3 to live (or program) source, then another light is turned on. Really, pretty simple operation.

Jeff :-)