Invisible powerpoint

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dpence9395

New Member
For the first time I put church service on Facebook Live streaming today. Two problems showed up. The first is probably my fault, we had an audio echo on the live stream probably caused by using separate microphone to capture audio off auditorium speakers. The second problem is where I need help. During the service we project a PowerPoint presentation on a screen behind the speaker from a separate computer from the one running OBS, a desktop dedicate4d to the live stream. While everything else streamed well the projected PowerPoint Image was washed out to the point of not being visible. After the services I changed the PowerPoint slides to a black background with white letter (from a light background with black letters) the letters of the slide would then show up but the background was a light yellow. What went wrong or what can I do to make the PowerPoint stream properly and am I right about the audio echo issue?
 
The audio will be much better if you use a direct feed from the sound system rather than a mic on the speakers. Ideally, you would have a second audio channel with a mic or mics pointed at the congregation. That way you can turn up the congregation when they are singing or praying aloud, but back off during readings or sermon to reduce echo. Google "crowd mic" for tips in mics and placement, but it doesn't need to be fancy. We just have a small diaphragm condenser mic (cardioid) aimed at our small congregation and away from the speakers.

Camera watching a screen is similar: never going to be as good as direct video. The low-budget way to do this is to run a copy of the PowerPoint on the OBS computer and stream THAT, changing slides in sync with what's on the screen. We have OBS scenes for full-screen PowerPoint, full-screen PowerPoint with podium camera as an inset, and PowerPoint and camera images of roughly equal size (lower left and upper right)

If you can get a video output from the projection computer, you wouldn't have to worry about changing slides, but that can be a pain/expensive if the computers aren't close to each other.
 
Yes, definitely, you want an audio feed straight from the mixer/sound system if at all possible. This could be analog or digital depending on your system.
- People will put up with ok video. If the sound isn't clear, folks won't stick around. So I'd focus on audio quality first and foremost.
- Then beware that if you recording locally, and check that it will sound a certain way (hopefully good). But then you livestream it and all content delivery networks (FaceBook, YouTube, etc) will re-encode and compress the stream (audio and video). And then most FB livestream audience is listening with poor mobile device speakers. So, test how service sounds over the livestream. Like FM radio, compression is sometimes recommended, but simply adjusting levels may suffice to start.

A key consideration is number and technical sophistication on livestream operators (usually volunteers).
Adjusting sound system during a service is common for some worship styles and is completely unheard of in others (like mine). Our system is set, and not touched for months at a time. With that said, our mixer does have a Main mix and an AUX mix/output. The main mix goes to the in-house speakers, while slightly modified settings are used for the AUX output to the livestream. We also have additional mics for the livestream, which are not amplified/Main out for in-house audience (ex piano, pipe organ, etc). And fortunately, we have someone who bought and setup the sound system as a parish member, and who helped out when we needed an alternate setup for livestreaming. I'm an IT techy, not a sound engineer, so his help was really valuable.
- Another thing is understanding OBS Audio. Personally I had no need for default Desktop Audio (and it was messing me up initially), so I disabled all of the default/Global Audio sources, then added an Audio Source for our Mic input only on those OBS scenes where appropriate (no reason for mic to be on during opening/countdown timeframe as people are connecting, and I've set up an automated, fade to black go in peace sequence at the end.

In our case, the sound system is in a closet, so I put the streaming PC in the closet, so I have a short connection from mixer to OBS PC. I then run a 50ft DisplayPort video cable (plus a high-quality powered USB cable for keyboard and mouse) up to the choir loft, and drive a dual-monitor setup from upstairs. I mention this as separating PC from keyboard, mouse and monitor is doable, at small expense, when needed. For us, PC stays locked away in closet with mixer, and network gear, which is a plus.

I also use PowerPoint for our Service Bulletin. In our case, I use PowerPoint in a windowed (vs Full screen) slide show mode and then have approx 1/3 on left side of OBS canvas for PPT slide. I then have scenes for "No Slide" [ie PPTx window capture turned off]; and Partial slide [where video image talking approx 5/6 of screen vs typical 2/3]. For Christmas Eve outdoor service, we switched to a gray background instead of white.
For us, 1 person running OBS PC
- monitors Scheduled Facebook livestream and comments (ie Digital Usher) in a browser session. Use Scheduled Event, so you get a consistent URL that non-Facebook users can watch (ie from Roku, smart TV, etc)
- changes PPT slide (in windowed mode like we have, we have PPT only partially visible) we can mouse over PPT and use scroll wheel to advance slide without ever making PPT the active window. Works well.
- manages PTZ camera (presets, camera controls, etc all done via software displayed on 2nd monitor)
the above is a fair number of balls in the air at once, and does take some training, but is totally doable for non-technical folks. I help out when tech issues, but weekly service OBS operations usually someone else at this point (started in March '20). Notice no audio adjustments at all during service. Though I am hoping before long to switch from an analog mixer connection to digital (USB) and get individual mic channel controls on OBS PC for some sound optimization (primarily to mute the pipe organ/choir mic when not in use due to a slight echo from main speakers impacting only livestream audience)
 
i would run NDI HX on the Powerpoint PC and OBS NDI plugin on the OBS PC you can send the audio from the powerpoint PC too over NDI

then connect the mic from the speaker to the OBS PC when you have a Audio Mixer use an aux out !
 
Cyclemat - I don't disagree, BUT... I'd want to test, as the CPU impact with same NDI setups can be significant, and that is an ultra-low power (laptop) CPU
 
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