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Author Topic: Get me started with a basic live video setup to feed overflow rooms  (Read 1870 times)

Corey Scogin

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Greetings. I'm a long-time live audio hobbyist and PSW member. I'm an EE by trade and the volunteer tech lead at my church. I have lots of experience with sound but not much with live video.

I am interested in setting up 2 or 3 overflow rooms with sound and live video fed from the main auditorium. This is a somewhat temporary / quick fix to help alleviate an overcrowded service. Only live A/V is needed right now but I'd like for the system to be capable of recording in the future (with additional purchases, of course). We tend to stay on the low-tech side of things so we'll likely never need much more than I'm asking for now.

I have the audio portion covered if it's distributed separately. I'm mainly looking for advice on what to purchase for the video portion and whether an integrated audio/video distribution solution is best.

We have no video equipment currently (except for a couple of spare small projectors).

I'm guessing we'll need:
A Video camera with live output capability (HDMI?, HD-SDI?)
A distribution hub (minimum 3 outputs)
Receivers to convert the transport format to HDMI or VGA before hitting the displays.
Some processing for time alignment? I can delay the audio side easily if needed.


The display portion I can figure out whether we use our existing projectors, new ones, or LCD panels.

What are some ways to accomplish this?
Any good resources you can point me to?
Any caveats to look out for?


Notes:
-The overflow rooms are in earshot of the main auditorium so the whole setup needs to have relatively low latency (~40ms at most) in order to ensure the
distributed audio is at least as fast as the sound propagating through the air.
-The stage lighting is not super bright so a decently sensitive camera will be best.
-The camera needs to be mounted at a balcony position ~30 feet from the stage and preferably operator-free.

Feel free to tell me I'm asking wrong questions as I know very little about modern video distribution or cameras used for such purposes but I am generally familiar with photography and videography concepts.

Thanks in advance for any help getting me started with this. I'm open to hiring an A/V contractor but I want to make sure I'm at least educated on these things before making that call.

Edit: PS, I forgot to give a budget number. I think $10k would be doable. As with most things, I'd like to spend as little as possible to get a "good" solution.
« Last Edit: August 29, 2016, 04:09:09 pm by Corey Scogin »
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Stephen Swaffer

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Re: Get me started with a basic live video setup to feed overflow rooms
« Reply #1 on: September 04, 2016, 08:24:19 pm »

I don't consider myself an expert, but in the absence of other responses, I will offer what we use an have used for years- though it is pretty basic.  We have used a consumer grade camera with an RCA out to a distrbution amp-it might even convert to broadcast channel 3 or 4.  Pretty old school, I know.  We used to use the camera mic, but now take the record fed off the mixer.  This mainly goes to our nursrey, but during special events we set up screens in multiple locations.  Quality is decent.  The camera sets next to me in a balcony media booth-other than making sure the CD deck is armed so we get audio and an occasional tweak of the picture due to the tripod getting bumped.

Simple, effective and virtually maintenence free.  Perhaps not technically the best.
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Steve Swaffer

Corey Scogin

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Re: Get me started with a basic live video setup to feed overflow rooms
« Reply #2 on: September 04, 2016, 08:44:58 pm »

Simple, effective and virtually maintenence free.  Perhaps not technically the best.

Thanks for the reply. I ended up with a more modern version of what you suggest. I bought the cheapest camera I could find with an SDI output and XLR inputs. That plus an SDI distro and SDI/HDMI converters. I wanted to use SDI because the locking BNC connectors are much more robust than an HDMI connector.

I'm setting it up this week. I'm a bit worried about the live output latency as it's 80ms at 30fps and 60ms at 60fps (specs I couldn't find in the documentation...had to measure them). I need ~40-50ms to align properly with sound from the auditorium PA in the next room. I'm hoping it won't be too noticeable. The camera is a Canon XA35.
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Jonathan Johnson

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Re: Get me started with a basic live video setup to feed overflow rooms
« Reply #3 on: October 27, 2016, 12:24:44 pm »

I'm setting it up this week. I'm a bit worried about the live output latency as it's 80ms at 30fps and 60ms at 60fps (specs I couldn't find in the documentation...had to measure them). I need ~40-50ms to align properly with sound from the auditorium PA in the next room. I'm hoping it won't be too noticeable. The camera is a Canon XA35.

Apologies for dredging up an oldish thread.

As a rule of thumb, due to the latency involved with digital video, for overflow rooms NOT within earshot of the auditorium, it's generally best to stream the audio with the video, then pull the audio for the overflow rooms from the video feed. That will keep the audio in sync with the video. Since the latency could be variable, trying to have a separate analog audio feed direct from the board with a delay might mean that you have to constantly tweak the delay. Doing this also simplifies things a bit, as you will have fewer cables to run. In this case, you are reproducing (rather than reinforcing) the audio from FOH.

HOWEVER, if your overflow area is within earshot of the main auditorium (that is, you get a significant amount of sound from the main auditorium into the overflow area), then it may be better to take an audio feed directly from the board (with appropriate delay for the distance), and not bother with the audio in the video stream. In this case, the video is only to provide visual enhancement, and the audio reinforces (rather than reproduces) the FOH system.

It sounds as though you pretty much understand this. I'm posting this for others reading this who are looking for a similar solution.
« Last Edit: October 27, 2016, 12:26:59 pm by Jonathan Johnson »
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Andrew Outlaw

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Re: Get me started with a basic live video setup to feed overflow rooms
« Reply #4 on: November 15, 2016, 04:48:03 pm »

If you wanna do this cheap but good, you're pretty much on the right track. For around 2 grand you can get a decent camcorder with an SDI output (camcorder also allows for recording). You can run the audio from your mixer into the camera (using it as an embedder), then run an SDI cable (basically coax rated for digital signal transmission, usually dual or quad shielded, with BNC ends) for up to 300' (roughly, dependent on transmission rate and type of cable) to the overflow room. Get a projector and screen or large TV w/ HDMI in (depending on size of audience), and an SDI>HDMI converter. make sure the SDI>HDMI converter supports embedded audio if running to a TV, if not you will need an audio de-embedder to run to speakers in the room. This method should have very low latency and little if any difference in sync of audio and video. There are ways to make that even better, but more $$$. Even if the room is in earshot of the main sanctuary I wouldn't try to delay the audio to the sanctuary's audio because it would throw the sync off of the video more.

Whole setup would run around 5 or 6k, which is a fairly sizable chunk for a stand-alone, stop-gap measure. Have you talked with your churches leadership about an overall vision, and putting together a comprehensive 5 year plan for AV? Would hate for you to spend this money now, only to completely re-do everything 2 years from now because a completely different system is being put in. I know you said this is all you would ever need, but if your church is running out of space, maybe the leadership vision entails in a few years getting or building a larger building, or having several small sites connected by webcast, both of which would completely change the game from what it is now. Just something to think/talk about.
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