DIY Digital Video Switcher

I’ve been looking all over the internet for what sounds to me like a relatively simple little machine. I basically want to have the ability to switch live between 4+ USB cameras and have one output without the need of a laptop. I don’t really care about video quality, I just want the cheapest, smallest solution. I know this would be a lot easier with analog inputs, but I have more tiny digital cameras than analog ones at the moment.

Any pointers or thoughts would be a huge help, I’m pretty lost.

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Everything sounds simple on the surface. :slight_smile: USB cameras are FAR from a simple thing, however. USB cameras, by their nature, will require a ‘computer’ of some kind. A Raspberry Pi or some similar small computer would probably be about as small as you’re going to get. And 4 USB cameras can be a struggle ever for a ‘real’ computer to handle.

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Hmm, that makes sense, thank you. So what do you think would be the cheapest way to do this with 4 small cameras? I was thinking of using some security style cameras or even backup cameras. Digital seems easier to power for a mobile setup than analog.

Many backup cameras and many security cameras are analog. :slight_smile: They are rarely USB and are usually just analog composite video.

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So what do you think would be the cheapest way to do this with 4 small cameras?

Cheapest would probably be a USB Switch and a small, (not too) old computer that’s capable of running OBS or similar software. There’s probably software out there in the RPi-verse that is capable of simply displaying whatever USB camera is plugged into its ports, but I predict the real challenge will be finding a solution that will play nice with rapid connects and disconnects from its USB ports, since that’s basically what a USB switch would be doing. Best case scenario in this instance would be a piece of software that automatically detects that a new camera has been plugged in and knows to switch to it, but I’d imagine that it would probably still need at least one (possibly several) second(s) to re-establish the USB handshake every time you’d switch inputs.
A moderately decent computer is probably capable of connecting to all the cameras at once via a powered USB hub into a single port on the PC, and I’m pretty sure OBS or other VJ programs can switch between those instantly once you set up each USB camera as an input in the software. But yeah, I don’t think there’s a way around requiring some sort of computer/software involved if you’re sticking with USB cameras.

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Exactly. The negotiation time of the disconnect and reconnect of the USB cameras would make this an exercise in futility.

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analog video Switchers as opposed to a video mixers are pretty cheap & lightweight peices of gear. This is assuming that you are cool with just either/or switching between the 4 cameras instead of being able to dynamically mix them in any way. a bit of work on ebay would probably net you 4 security cams and a switecher for under 100usd.

for usb stuff, it would mostly be a pain due to all the reasons folks have listed above. nano computers like any pi will all be fairly useless for a 4 cam setup. what you would really want for 100 percent success would be 4 seperate usb busses inside of a computer with seperate power and data lanes for this to work efficiently, and even then there might could be some issues with ram & buffering. a place that i would start with this is a motherboard that has at least 2 seperate usb busses built in and just test with 2 cams on each bus to see how that works, then pick up some pci usb expansion cards if needed.

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Thanks for all the info.
I don’t really need to mix the videos (although it would be a fun plus) - just want to be able to switch between the sources as quickly as possible. Based on all this info I’m going to go analog and try to build the switcher myself. I’m imagining something with 4 buttons that correspond to the sources, so when you hit a button the output switches to that source. Is this possible without much experience past knowing how to solder?

You will have momentary losses of sync during switching since the signals will not be synchronized in any way.

I’m cool with that.

Make sure that your destination for the switched signal is. For example, many TVs and projectors will flash a blue screen while they resync.