View Full Version : Streaming Tricaster Feed in a Conference Call Setting

05-23-2017, 09:40 AM

Ran my first event with the Tricaster Mini (HDMI, Standard Edition) last week and while the device and the recording performed smoothly, there was an issue that our recipients had that we couldn't fix at the time of the event.

The long and short of it was that our recipients were getting an audio delay that causes the video feed to become de-synced throughout the conference call. We had to immediately upload the recording elsewhere to compensate for that. Despite our recipients getting a de-synced feed, our feed from both the Tricaster and the host computer were perfectly fine (even when the conference call app recorded the call).

Our setup was this:
-Tricaster Mini (HDMI)
-3 cameras (1 stationary, 2 PTZ)
-4 wireless mics connected to 2 analog mixers that fed into the audio in ports (2 of them being part of a speaker system)
-NDI Transmit and WebEx call running on the same computer
-NDI Scan Converter and Powerpoint running on a different computer
-Video was recorded at 720p/30fps, transmission was matching source for clarity (we did consider transmitting at 480p, and while it synced up, the video quality was lower)
-Tricaster and WebEx call were part of the same Gigabit ethernet network; recipients were getting the call wirelessly, usually in places with low or somewhat decent bandwidth

Is there anything on the Tricaster end that we can fix to improved the situation? (I'm confident that there isn't, but I can always be wrong) Or is it all on WebEx's end? It may not be the recipient's internet connection since we have tested the situation with those who had stronger internet, and they were having the same issues. The reason we have it set up this way is so not only that the audience can interact along with the live broadcast, but that we can have control over the interactions as if they are actually here in a live audience setting without actually being present. Please give any advice that you may have on the situation, as well as any alternative solutions for a similar kind of setup. Thank you.

Matthew Baran
Lutheran Church Charities

05-24-2017, 06:20 AM
I would think that it might be Webex. That is where I would look first. Is it possible that there was some type of error with Webex and NDI transmit? Maybe something with the gpu drivers on the computer. Do you have a way to take HDMI out directly into the Webex computer? To try and trouble shoot that is the first thing that I would do. Recreate but take NDI transmit out of the mix. Then go connection by conncetion from there. Good luck with finding your problem.

05-24-2017, 06:51 AM
As a possible alternate solution, give http://www.gnuralnet.com/ a call to see if their products could work for your needs.

Their products work great with TriCaster taking full advantage of the NDI workflow

06-01-2017, 03:35 PM
I was able to look into the network activity a bit more and I have a couple more questions. First off, is NDI Transmit just taking an uncompressed signal of the live feed from the Tricaster? If not, then what is it exactly doing when moving from the Tricaster to NDI Transmit in order to be placed in a conference call? That could be why everything is out of whack because I’m getting a signal of anywhere between 30-70 Mbps on average, and from the information I’m getting from WebEx, they usually handle about 3 Mbps with webcams. Is there any way to control the bit rate or compress the NDI signal? Also, I tried switching between 720 and 480 via NDI Transmit and I haven’t had any changes to the bandwidth transmission. Does anyone know why that is the case? Thank you.

Matthew Baran
Lutheran Church Charities

06-01-2017, 08:10 PM
Hi Matthew,

In my experience with NDI Transmit, it's providing a stream that emulates a USB camera to the client software. So, it's important to know what kind of PC and video card are in it, as that's handling a huge load of downconverting, compressing and streaming into the client app (WebEx).

I've also noticed in my few experiences with WebEx that it's not particularly good.

Now, given the above, I've used a pretty underpowered computer to send to Skype with NDI Transmit and NDI Scan converter (these have been as a poor man's version of Talkshow) which ran quite well on both ends.

I suspect that WebEx is ending up splitting the video and audio data stream in the PC before it even goes out and that's where the problem lays.

Since you're local, if you'd like, I'd be happy to show you how I'm doing it (you can sometimes see the results on WYCC, too).


Fritz Golman
Museum of Broadcast Communications

06-02-2017, 08:37 AM
That would be very helpful Fritz; thank you very much for the advice. I am interested and would like to see a demonstration. Would that be better online or in person?

Matthew Baran
Lutheran Church Charities