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SOLUTION for 2 simultaneous streams with Blackmagic capture devices!


I almost ended up purchasing Wirecast, until.....

So - like me you wanna stream your Blackmagic live source(s) simultaneously to both Facebook and Youtube? I'm a pianist and need a multi camera setup streamed to both Facebook and Youtube, since the FB stream will give me a much bigger audience but YT will give me the better quality, especially better audio. I discovered that the FB live stream audio is VERY compressed and the result is even mono, although the stream is stereo. For the piano sound it was crucial for me to have good audio in a secondary stream.

I thought I would share this workflow to you, until a real multistream feature will be implemented in the future. This is for Mac OSX. I have a Macbook Retina 2012.

As pointed out in earlier threads, if opening two instances of OBS, only one is able to give you an image of your Blackmagic sources. You could send your stream to and let it send to both FB and YT, but Facebook streaming through this service is a paid option only.

What you can do instead: Go to
and download the Black Syphon utility. Open the software and set your desired resolution. I own both an Ultrastudio MiniRecorder and Ultrastudio Express and they are connected to each Thunderbolt port of my MBP. Both will show up in the list. Black Syphon is will give you a preview of the selected source and route them to whatever software will pick them up!

Start OBS and add some scenes. Add a "Game Capture (Syphon)" source to the preferred scene and choose your preferred [Black Syphon] Blackmagic device(s). Make two profiles - one for Facebook streaming and one for Youtube streaming.

Open another instance of OBS by opening the terminal window and run the following:
open -n -a /Applications/

Voila - Black Syphon is routing your Blackmagic devices perfectly well to both OBS instances! Now choose your FB profile for the one instance and YT profile for the other instance and start the streams!

Of course the fans will be a little louder since the processor load is twice as heavy when encoding two separate streams, but I did not experience any trouble at all during 90 minutes of continuos streaming. I even have my iPhone as Cam3 with the excellent Epoccam app also running via Syphon. Soundwise I have two USB adapters connected at the same time (Apogee Duet2 and Roland R-26), one for a stereo mic setup and the other for a microport. I also use the excellent "Automatic scene switching" plugin to automatically switch between my cameras while I play!


Jacob Nielsen
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