I have been using OBS and Wirecast, applications that work on Mac and Windows computers as a live video switcher and streaming program. I last used these apps for live switching between the presenter’s on-stage Windows laptop running PowerPoint, and the MacBook Pro Retina behind the stage running the videos. Using Wirecast on the Mac, I digitized the PC laptop’s HDMI video output with a 25 foot HDMI cable to a Magewell video digitizer, which was connected by a USB 3.0 cable to the Mac. Wirecast allowed me to que up video clips ahead of time to play during the program, or display the Powerpoint slides during the presentation.
If I had a second HDMI source, I could bring that in to Wirecast as another input, using a Blackmagic Ultrastudio Mini Recorder to Thunderbolt cable in to the MacBook Pro Retina. Since I have two Thunderbolt ports, another Ultrastudio Mini Recorder could be supported. The Desktop Video camera on the MacBook Pro Retina can also be a video input to Wirecast. Video inputs can also be added through the Magewell USB 3.0 device, which I find more reliable than the Blackmagic digitizer. I find the Blackmagic can be finicky about the HDMI video signal and lose connection sometime. Also be aware that you can’t reliably send a video signal over 25 feet. If you need to go further than 25 feet, you need to convert the HDMI video signal to DVI or SDI, to travel a longer distance. These types of video converters are available from Blackmagic and other vendors. Be aware that direct sunlight and heat can be a problem with this hardware, and interfere with reliable performance.
Wirecast allows you to use your computer as the video switcher and live streaming program. It can be used with multiple audio and video inputs. I use it with my 4K Panasonic GH4 DSLR and 2K Sony NEX-VG20 video camera. The Panasonic GH4 has a microHDMI port for the video signal out, which I plug into a Magewell unit, then plug the USB 3 cable into the Mac. The Magewell device, at $300, is more reliable for Mac, Windows and Linux video, because the drivers and memory needed are built-in. The Sony NEX-VG20 video camera has a miniHDMI connector for the video out, and I plug that cable into a Blackmagic Ultrastudio Mini Recorder to Thunderbolt cable, at about $200, in to the MacBook Pro Retina Thunderbolt port. With each video input that you add, you can specify which audio to use. You would probably change the audio input to the best audio input you have set up. I use my Zoom HR5 audio recorder as the audio input, which would have as feed from the sound board. If you don’t switch the audio, the camera’s onboard mic audio will play when that source is selected for the live show.
Wirecast lets you record your program to your local drive, while streaming to Ustream, Livestream, YouTube or whatever streaming service that you set up. This setup would also support a Blackmagic 4K Television Production Studio (up to six HDMI sources and switcher) HDMI input through the Ultrastudio Mini Recorder or the Magewell unit to the computer, which would record and livestream the program.
You could use two Magewell units, and two Blackmagic units with the MacBook Pro Retina to perform a three camera shoot, plus a video input from the presenter’s laptop, to live edit and stream a professional show. You could also do this with the new dedicated Wirecast Gear live streaming production hardware that Telestream has put together, starting at about $5,000. The closest thing to this on the market is the Newtek Tricaster.