ATEM Mini Pro Upstream and Downstream Keys Explained

on this episode of create consumer repeat i'll show you how to hack the downstream key and use it for more than static bugs logos and lower thirds so stick around on a previous episode i showed off this animation which had many of you in the audience scratching your head wondering how the hell did he do that well up until this point i've shown you how to run complex animations on the upstream key by leveraging the chroma keyer which for all intents and purposes is also a hack which i'll explain in detail later on in this episode now in order to show you how i'm able to run animations on the downstream key i need to explain the differences between the upstream and the downstream keyer and their respective limitations so without getting too into the weeds the downstream and the upstream keys work in layers kind of like a photoshop file with the upstream key being a layer below the program input and the downstream key resting a layer above your program input in addition each key has specific masking capabilities that allow you to control what you see at any given moment and to help illustrate this i've created a diagram that mirrors the options of the switcher now here's where it gets a little tricky as i mentioned earlier the upstream and downstream key have different masking capabilities the upstream key can mask using one a luma key which is sometimes referred to as a self key because the same video source is used for cutting the key and overlaying the video image luma keys work best with high contrast images like white elements on a black background two a chroma key which removes a specific color usually green or blue and replaces it with another image such as a video or graphic three a pattern key which is usually used for creating wipes the most infamous example can be seen in star wars a new hope and for the linear key or as it's more commonly referred to the alpha key which sends a separate video signal to the keying device that contains the key information this video signal just looks like a grayscale image and defines exactly the transparency of the way the fill signal is supposed to be overlaid on the background with that out of the way we can focus our attention on the downstream key which is somewhat limited by comparison because it only offers an alpha key and i know what you're probably going to say next alpha keys sound really really powerful and they are and to be honest i actually think they are the most powerful sadly the a10 mini line of switchers only allow you to use pre-multiplied alpha channels with static images from the media pool unless of course you own a hyperdeck now for those of you that are long time fans you're used to me demonstrating alternatives to purchasing a hyperdeck since you can do 80 of what the hyperdeck does using a computer running obs hooked up to an hdmi input regrettably that final 20 equates to a huge leap in performance that takes your motion graphics to espn levels of broadcast quality and the reason it's such a huge difference lies in the device's ability to output a key and fill in perfect sync which in turn allows you to output motion graphics with perfect alpha transparencies now all this power does come at a cost one being financial since you not only need to purchase a hyper deck you also need two sdi to hdmi converters two sdi cables and two hdmi cables and the other being the loss of two ports on your atem switcher one for the fill and one for the key and let's be honest that dramatically limits your switching options by half unless of course you have an a10 mini xtreme which has eight hdmi ports with all that out of the way i am now finally able to show you how you can hack the downstream key the moment you've all been waiting for just like the chroma key exploit i've shown you in previous videos this relies on the use of a computer running obs plugged into an hdmi input and instead of using a chroma key green background in obs you're going to be putting all your animations over a black background yes black background very important now before we head to the atem software control panel right click and select windowed projector preview when the window pops up right click on the screen and select full screen and select bmd hdmi which should be your secondary display and for you longtime fans this is all pretty rudimentary by now the last thing we have to do now is change the fill and key source in the atem software control downstream panel to the hdmi input your computer is connected to in my case it's hdmi 4 which i have titled imac and with that you now have an animation playing on the downstream key yep that simple obviously this hack is limiting because you can no longer use the color black in any of your graphics since it will immediately be keyed out as you can see in this example right here and this is where the hack requires a little bit of effort and creativity since you now must shift black to a lighter shade and adjust the pre-multiplied key clip and gain settings to dial in your graphic but let's say you do have a graphic that truly does require black and there is no way around it one workaround is making sure that animation remains in a static position on screen that means no transition on and off screen and you create a pre-multiplied field graphic that will only serve as a key i use this same technique in a previous episode demonstrating how to do a one-on-one split screen interview which you can find right here the main takeaway though is that no matter what you do you will not be able to implement motion graphics with smooth alpha transparencies which let's be honest is a huge bummer but if you really need that functionality then i would highly recommend purchasing a hyperdeck studio hd plus yes you heard right personally though for the stuff i'm doing it's not that big of a deal to work within these constraints not to mention 850 is a ton of cash to spend on all that equipment that'll do it for this episode and if you have any questions or comments leave them in the comment section below and don't forget to smash that like subscribe and bow so you're notified when i drop another episode catch you guys next time [Music]

Channel: Create. Consume. Repeat.

Views: 21,437

Keywords: atem, switcher, key, blackmagic design, upstream key, downstream key, atem mini pro, tutorial, chroma key, luma key, pattern key, alpha key, hyperdeck studio hd plus

Id: w8yJc_Uqd4E

Length: 7min 11sec (431 seconds)

Published: Thu Oct 21 2021