I'm working with ATEM Production Studio 4K from Blackmagic to switch between several video feeds that are broadcast using Wirecast onto Youtube from a Mac. Our ATEM product is not one of the switchers that comes with DVE (aka the ability to resize video input). I want to find a way to resize a video input and combine it with another input so I can broadcast the video to Youtube.

There are two video feeds I want to combine, a feed from presentation software and a feed from a camera filming a presenter, in a way that the presentation is smaller than full screen and moved to a corner.

I've considered ffmpeg, but I don't know how to use ffmpeg on a video stream in a way that we can combine it with another stream and send it into Wirecast, if that's possible.

An ideal solution would take a feed from our switcher and another feed from our presentation software, resize the presentation, combine it with the switcher feed, and send the result to Wirecast or Youtube. Is this possible to do for less than the cost of a new switcher? Is there a way to do this using OBS in place of Wirecast?

  • 1
    ffmpeg should be able to ingest feeds from Blackmagic devices, do the scale & overlay, and then stream directly to youtube over RTMP, bypassing Wirecast.
    – Gyan
    Commented May 11, 2016 at 19:37

2 Answers 2


How are you routing to Wirecast? SDI/HDMI to thunderbolt? An easy solution is to get a micro/mini recorder from blackmagic and pull in that second feed directly to Wirecast through thunderbolt. Then in Wirecast you can mix the program feed and the second feed while adding layers of graphics. We do it all the time during live broadcasts. Also, having those micro/mini converters from blackmagic are priceless to have in general and they don't cost much.

  • Is there a way to get the feed into Wirecast if it's already going to the switcher? I think the Recorder might help pull the feed into the computer and then into Wirecast, but we need it on the switcher, too.
    – user14581
    Commented May 12, 2016 at 21:04
  • Great question. You indicate that you have the ATEM Production Studio 4K? For this you will need to split the SDI/HDMI feed prior to sending it to the ATEM so that you can route one feed to the ATEM and the second feed into the computer (by using a mini/micro recorder). In my case, we opted for the ATEM 1/ME Production Studio 4K because then we can route route directing into the swisher and then use an auxiliary port to send any one input out of that aux port to the computer (no need for a splitter). Commented May 12, 2016 at 22:44
  • Also, most Blackmagic production gadgets have re-clocking and multiple outs that are cheap. Again, the more devices you have in your gear bag the better for times like this :) Commented May 12, 2016 at 22:45

You can do this with OBS. I do it all the time.

The Mac, can with OBS take the feed(s) and arrange/resize them and then stream it to Wirecast(?, but not necessary) or directly to Youtube.

OBS handles both input from streams and from video cards, so you can have several inputs and combine them, very easily.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.