Bizarre issues with HDMI capture devices

ghgrjdghgdndgz

New Member
Need to get two DSLRs into OBS, so the obvious choice is HDMI capture - both DSLRs output clean on their HDMI ports, and mucking around trying to get them working over USB has simply proven impossible. Even Sparkocam only allows 640x420.

Anyway, I now have an Elgato Game Capture HD, and a Lindy HDMI to USB device. Both work fine, but there's some very odd discrepancies between them that I just can't get my head around, and I don't know whether to blame them (either Lindy or Elgato) or whether it's something I'm doing wrong.

- The Lindy device is great in that there is ZERO delay on there. I mean, there must be a few ms but it isn't noticeable. This is fantastic as I assumed all HDMI capture devices had some delay and you just had to live with it. Yet despite being 1080p in the specs, it is only showing up with a 720p option in OBS. Is this something I've set up wrong? I can't get it in 1080p. They list OBS as the first piece of software it was "officially tested with" in the manual, so it's not like it's not designed to work in OBS.

- Meanwhile the Elgato device is fine with full 1080p, but is really "shonky" for want of a better word. There's horrible delay (about two seconds), and you have to muck about opening the Elgato Game Capture software to get it to initialise. Once it finally fires up in the Elgato software, it won't work in OBS as it just says "In Use By Another Application" so you then have to close the Elgato software and hope it doesn't trip the Live View on the camera out and you have to go through the whole thing again.

In general too - whenever I change something hardware wise (turn a camera off, Live View goes off, a cable is pulled out/swapped), OBS won't refresh the scene. You have to go into the source, change the device to something else, then change it back before OBS shows the live feed again. Is there a way to make it so that OBS will just resume as normal once the camera/source fires up again?
 
The Elgato Game Capture HD is a USB2.0 device. Because of this, it has a bandwidth limitation, requiring all video data to be compressed using its on-board h.264 compressor, which adds the delay that you experience. The issue of drivers is due to this device being very old, prior to windows UVC even being a thing. More recent capture cards will have much fewer issues with OBS, especially if they support UVC.

According to everything I can find, the Lindy device you have is a USB3.0 capture device. This does not have the bandwidth limitation, and can send uncompressed frames with no delay. I have never used this device myself, but I would imagine it does not have the ability to do any sort of resolution scaling. Whatever it is receiving from the HDMI signal should be what it is outputting... so if it's outputting 720p, that likely means that it's being fed 720p.

For resetting input devices, you can go to the source's properties, and press "Deactivate", then "Activate". This works around the need to switch the actual source, and should work just as long as the capture device's identifier hasn't changed. Some devices may also need the resolution/framerate set manually (which may be the case for your Elgato).
 
Thanks for the reply, very helpful.

Totally makes sense on the Game Capture - that explains the delay thing totally.

On the Lindy device - I'd never heard of it either. I only heard of the actual company a month or so ago trying to find a USB extension cable and ended up buying HDMI cables, USB switches, and even a power extension 6-way. All beautifully made with great attention to detail. The fact I found their HDMI-USB thingy was pretty much coincidence, and I went for it only because I thought "these guys make a cracking cable, this thing can't be total dog shit" and turns out it's great. I'm just incredibly annoyed it's advertised as 1080p out of the box (they have no drivers for it) and it won't show up as such.

The cameras I'm using do output at 1080p because I've got them working at that resolution with the Elgato, and indeed one of them is a "top-end" Nikon D750 which outputs clean uncompressed 1080p from it's HDMI output.

One possible thing I'm thinking is that given it says "USB 3.1" on the back, it needs a USB 3.1 input to output 1080p maybe?
 
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