Hello everyone, first post here. Very much love being part of the video circuits community and very much excited to discuss my personal A/V gear on scanlines in the future (recently picked up a Kramer FC-4001 that i’m looking forward to learning about & testing out).
For now though, I have a question regarding sending multiple videos to multiple (HD) screens. I would like to ask for guidance regarding this. It’s basically for a small gallery, and we don’t want to have to buy multiple memory sticks and load videos through this method. There has to be a way that one computer (or Raspberry Pi?) can send out video streams to multiple HD screens/modern day flat-screen TVs.
Apologies about the noob question, and if it’s inappropriate for this forum then i’ll happy delete it (or mods can take it down). Thanks for all help and guidance in advance.
Caveat: I still feel like a noob after doing this for about a year, so there may be others who will have better/more complete answers than I.
There are a few different configurations, and what you want depends on which configuration.
Many in → many out (this sounds like what you are describing)
If you have different videos you want to play on the screens (as in video A plays on screen A, video B on screen B), then a matrix switcher could work. There are HD matrix switchers out there, but I’ve only played around with SD (composite) ones. Matrix switchers tend to come in multiples of 8. An 8x8 matrix switcher will have 8 inputs and 8 outputs and you can configure it where input 1 goes to outputs 1,3,5 and input 2 goes to inputs 2,4,6, or any permutation with the limit of one input into each output (will not combine or mix multiple inputs into the same output). I have also seen 16x16 and 32x32, but 8x8 is more common. Kramer and Extron are two common manufacturers of these products, at least in the retro SD versions that I shop for. There is likely some kind of limit of how many distinct outputs you can get out of whatever computer you are using, but each video will need to be on its own cable for a matrix switcher to work for this setup.
One input > Multiple outputs
For this, look for a “distribution amplifier” there is some discussion of (SD) ones in this thread Video amplifier - #7 by pixelflowers other terms I have seen are “video splitter”
One input cut into blocks so that multiple monitors that are next to each other make up a video wall (i.e. the top left corner of the source video is displayed on the top left monitor etc.)
There are probably high-end devices to do this for HD, but there was also a “Pi Wall” project to do this with Raspberry Pis, however it hasn’t been kept up to date with the Pi 4, and it’s hard to obtain enough Pis of the model needed to run it. More discussion of that concept in this thread Different options for contious CRT video wall - #10 by jotta_rs.
Correct me if I’m wrong, but you can only get one or two video outputs from a Raspberry Pi, depending on the model. The Pi4 added a second HDMI, but all the ones before it had a single output. A matrix switcher isn’t going to give you any additional outputs. Besat case scenario for playing two different videos out of a Raspberry Pi is using a Pi4 and both HDMI ports. Other than using hacky things like DisplayLink (not recommended because of CPU hit), you’re not going to get a Pi playing multiple files to multiple displays.
Although I’m not personally an expert with hands-on experience using it, I have a strong feeling that NDI Tools (from a quick glance, NDI Router in particular) would be able to facilitate this sort of thing handily over a local network. NDI is essentially a free suite of applications which enables an array of web-connected devices to share live video streams between each other without a wired video connection going from the host PC to each individual monitor.
Obviously there may be several obstacles/caveats to using it given your specific venue/hardware situation, notably the fact that each display will probably require being connected to its own computer/device that is connected to the the web with NDI Tools installed on each one. Which maybe already comes into conflict with the premise of your query, so forgive me if this suggestion might not be helpful. But I don’t think the NDI ‘receivers’ need to be hi-spec or anything, pretty sure older PCs/Macs or even a Pi4 will suffice for installing NDI to receive a stream. Even with the circumstance of needing one device per monitor, I reckon it’d still probably be loads cheaper than a fancy HD matrix switcher or similar.
Going down the NDI route may or may not be worth the effort to implement depending on how many displays/NDI-enabled devices you need to light up for the event, but it’s definitely worth looking into because it is scalable for sending a large number of different live video streams to a large number of different displays from a single interface, definitely more than would normally be feasible than a single PC’s display outputs or a dedicated hardware matrix. Just look into it a bit and see what it might be able to do for you, could be a rad solution if it works!
if you are a small gallery without a lot of $$ to spend and tech nerds to throw at problems, memory sticks will be your best bet. next up would be brightsign media players, theyre are great investments for plug n play, or raspberry pi 4s for if you want to put a small bit of overhead into things. the only reasonable way to have 1 source for multiple HD video outputs would be a pc tower with a couple of video cards with multiple video outs on each, which if you don’t have already, is gonna get a bit expensive and be a bit single purpose. of course the real question is by HD do you mean 720, 1080, 4k?
