ProPresenter Tutorial: How much latency does the live feature add?
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On today’s ProPresenter Show (brought to you by ChurchTechU.com), why you should not use ProPresenter’s live video feature to put live video on your screen.
One of the questions I get over and over and over again is how to use the live video feature in ProPresenter.
I always advise against using it. The right way to do it is to take the output of ProPresenter and send it into a video switcher. The reason you don’t want to use ProPresenter like a video switcher is latency.
According to an article I found on Wikipedia, the standard for latency between audio and video for broadcast television is 45 milliseconds or about 1-1.5 frames (at 30 frames a second). It also said that most people don’t notice lag until 100 milliseconds or more (which is about 3.3 frames).
So, I thought I’d do a little test. I created a 3 minute counter in Final Cut X and exported it as a 30 frame per second video.
Next, I brought that into ProPresenter 6 and put it onto the slides layer, so I could resize it.
Then, I added my Logitech C615 webcam and put it right next to the countdown, aiming it at the counter on the screen.
As a result, I had video of the counter showing right next to the counter itself.
Now, I just took some screenshots, shut down ProPresenter and restarted it again, taking some more screenshots to make sure the results were the same.
As you can see, there were discrepancies of between 6 and 8 frames.
Keep in mind that this is with a brand new, 2017 core i5 2.3 gigahertz MacBook Pro with 8 gigabytes of RAM and an SSD.
Perhaps it’s possible to get better results, but for most churches, this is about the best you can hope for.
So, using the live video on the screen, you’re going to have about 200 milliseconds of lag, which is twice as much as when most people would start to notice AND 4 times as much as is standard in broadcast.
For the occasional baptism or children’s choir performance, this might be okay, but for your entire service, this is probably just too much.
Now, to show you what this much latency looks like with a person, I’m going to intentionally put my video 7 frames out of sync with my audio.
Watch what happens when I clap and what happens when I move my hands (notice the picture in picture box that shows what it’s like in real time versus delayed.
So, I hope you see now why I don’t want you to use ProPresenter’s live video function to show video live on screen.
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About this show:
This show started with Renewed Vision’s ProPresenter software, but might include Photoshop, Final Cut Pro, or any of the other web services that churches might use.
If you do tech at your church or you use computers to advance your church’s mission, this show is for you.