HOW TO: Use Transparent Background

OnTheAir WebLink supports HTML 5 transparent backgrounds, perfect for web-based graphic engines. It means you can use the four channels as graphic outputs.

How to Set Up ?

1. First, create a graphic in your live graphics platform. Use its URL on one of your four OnTheAir WebLink Channel. Here is an example of a graphic created with Uno Overlays, used as an output in OnTheAir WebLink.        
2. Now, you need to remove the background. Go to the output settings of the channel.
3. Then, disable the Background option at the bottom left of the output settings.
4. You also have to put the Pixel Format to ARGB. When Premultiplied Alpha is enabled, it applies the transparency (alpha) to the color of the graphics. When disable, the outputting is straight.
5. If you look at the channel, you can now see that the background has been removed. Only the graphic will be visible in the output.

Keying for Local Outputs

All local outputs (Blackmagic Design, Deltacast and AJA) have the “Keying” option. Information about the OnTheAir WebLink Outputs in this article: 

https://softron.zendesk.com/hc/en-us/articles/13181435845916-Different-Output-setup-for-OnTheAir-WebLink-Local-NDI-and-Virtual-output

Here is an example with a Blackmagic card, note that this option is available with the other video cards:

Note that Keying is only available with ARGB Pixel Format. You have two options:

• Internal: the video card receives the input signal and overlays the graphic on top of that incoming signal, and outputs the result It’s the video device you use that does the keying.
• External: the video card generates both fill and key signals. Keying will be made by an external keyer (for example in your video mixer). This option is what most users need for their setup and for those who use video switcher.

Note that:

An NDI Output is always External. It is sent out to your network. You can then pick it up from softwares, hardwares that receive NDI signals. Here also you have the choice to enable premultiplied alpha.