To read the full product description of the Alpha Keyer Module, please visit our Alpha Module product page. This article assumes you have the correct hardware and have already purchased or are demoing the module in ProPresenter 6.
This Knowledge Base article will help you with activating your module if you have not already done so.
If you have not already done so, you will need to first install the Blackmagic Desktop Video Utility from the Blackmagic Support page. The software is listed in the Latest Downloads column below the Product Family. Click the link for the Mac or Windows version of the software. You can ignore the form and just click the Download Only link at the bottom left corner of the pop-up window unless you want to register a new device. Install and then launch the software. On Windows, just search for "Blackmagic Desktop Video Utility". On Mac, it's added at the bottom of System Preferences.
Your device will show up on the window when the Desktop Video Utility opens. Click the device image to adjust your settings.
These settings may vary depending on your device. In general, you will select the proper Video Input, set your Output Format, and uncheck the Remove Field Jitter On Pause. All other settings can be left alone unless you have been told to specifically change them by your system integrator or someone from Renewed Vision.
Open ProPresenter's Preferences and go to the HD-SDI tab to configure the module. You will likely only have one Device listed, but if you do have more than one, select the correct one. The Mode should match your switcher and the Blackmagic Desktop Video settings in System Preferences. If you are sending your signal to a video switcher, select External Key to send a key and fill signal to your switcher. If you are bringing your signal into ProPresenter, select Internal Key to keep your video signal active at all times behind your content. With Internal Key, you can bring one channel of video into the card and output one channel from ProPresenter. The video source is rendered on the card itself, so there is very little latency added to the signal as it returns to your switcher or display.
It is unlikely that you will change the Blend option. The Ignore Background Colors will allow you to change the slide background color if you need to in order to see your slide text easier. This color layer is ignored when it is selected. If it is unchecked, changing the background color of the slide or document will cause the module to treat it like a background image. Using the default background color set in Preferences does not impact this setting.
You will also need to configure the Output window size so that ProPresenter can format your slides and media to the correct size. In Preferences, click on the Display tab. Uncheck the Scale to Fit Output Display option and manually enter the resolution you need to output. If you use the wrong size or leave the scaling option checked, your signal may be distorted.
The Alpha Keyer Module generates a two-part signal. The first part is the Key, which is shown as a white with an opacity of 0% to 100%. This tells your switcher where the content is on the slide and what the opacity of each pixel is. The second part is the Fill. This is the content that goes in the key area. In the image below, the black background only exists due to the screen being black. When keyed over your live video source in the switcher, the black will be replaced by the video source. Everything else will be shown. The benefit of using the Alpha Keyer Module versus a standard linear downstream key is that you can use a black outline or include black in your content. In a standard DSK, you are typically keying on a color--usually black--so you can't use that color at all in your content. With this key, it is simply based on where content exists and the opacity, not the actual content or color of that pixel. As shown in the second image, if you have a full-screen background, such as a video or image, playing in ProPresenter, it will be seen as part of the Fill.
Connecting your Blackmagic hardware is fairly standard, but particular connections and settings within your switcher will vary by brand. The image below shows a very basic setup using a Blackmagic Ultrastudio 4k and a Blackmagic ATEM 1 M/E Production Studio 4K. The module requires two SDI signals from the UltraStudio 4k into the production switcher. The diagram shows going into SDI 1 and SDI 2, but you may consider connecting to the last two SDI inputs on your switcher depending on what your connections look like. This is entirely up to you and your patching preferences. After you have made the physical connections, you will need to configure your switcher's key settings to assign the key and fill inputs internally. We can't provide instructions for this since it varies by manufacturer. If you aren't sure, please refer to the documentation or support department for your particular switcher.
For a full list of Blackmagic hardware options that are compatible with the Alpha Key module, please refer to this Knowledge Base article.
Below is a chart that shows which devices can alpha key and what their supported resolutions are.
|Device||Internal||External||SD||HD to p30||HD to p60||UHD to p30||UHD to p60|
|DeckLink SDI 4K||yes||no||yes||yes||yes||no||—|
|DeckLink Studio 4K||yes||yes*||yes||yes||yes||no||—|
|DeckLink 4K Extreme||yes||yes||yes||yes||yes||yes||—|
DeckLink 4K Extreme 12G
|DeckLink 4K Pro||yes||yes||yes||yes||yes||—||—|
|DeckLink Quad 2||yes||yes||yes||yes||yes||yes||yes|
|DeckLink 8K Pro||yes||yes||yes||yes||yes||no||—|
|UltraStudio 4K Extreme||yes||yes||yes||yes||yes||yes||yes|
|UltraStudio 4K Extreme 3||yes||yes||yes||yes||yes||yes||no|
|UltraStudio 4K Mini||yes||yes||yes||yes||yes||—||—|
|UltraStudio HD Mini||yes||yes||yes||yes||yes||—||—|
—= Video mode not supported for playback
*= SD only
**= Over PCIe only