Issue setting up multiple video cameras

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deg2023

New Member
I am trying to connect three Sony Handycams to OBS, through a powered USB hub to a HP laptop computer. All three cameras show up in OBS, but I can only get video from one camera. Everything else produces a black screen. If I connect, just one camera to the USB hub and one camera into the unused USB port on laptop, I can get video from two cameras. Is there anyway I can get the third camera to work?

I believe I read where this isn’t possible, but I spent so much time on it, I’m reaching out for any help before giving up. Thanks in advance for any advice, Dave.
 
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JohnPee

Member
The limitation on the number of USB-connected cameras is the internal bandwidth available to the USB port. As a rule of thumb, one internal USB hub can only support a single camera. To determine how many USB hubs your laptop has you can use USBView from Microsoft or any other program that will show you the USB connections on your laptop. You can then rearrange the cameras to connect to separate hubs if you have enough available.
 
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deg2023

New Member
JohnPee said:
The limitation on the number of USB-connected cameras is the internal bandwidth available to the USB port. As a rule of thumb, one internal USB hub can only support a single camera. To determine how many USB hubs your laptop has you can use USBView from Microsoft or any other program that will show you the USB connections on your laptop. You can then rearrange the cameras to connect to separate hubs if you have enough available.
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Thanks John. I was afraid that would the the case. At least I can use 2 of the 3 cameras and also have access to the laptop camera.
 
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konsolenritter

Active Member
If your setup is otherwise working perfectly and stable for you (aside of the number-of-cams-issue)

/and if/ your sony handycams do support cleanfeed (no menu entries and overlays in hdmi) on their hdmi outputs, you may rethink your strategy towards using a blackmagic atem (just for switching) in front of your streaming machine. This way there would be alot of processing demand taken from the machine. Of course it costs a couple of bucks...
 
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Lawrence_SoCal

Active Member
JohnPee said:
The limitation on the number of USB-connected cameras is the internal bandwidth available to the USB port. As a rule of thumb, one internal USB hub can only support a single camera.
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Uh, that seems a little too simplistic to me ... as which version of USB will greatly impact the answer as well as camera resolution/bitrate (not to mention specific USB Root Hub chipset(s)). With USB3.x, multi-USB cameras often work ... but it depends (and then gets technical)

Search threads in this forum which reference "USB Root Hub" and/or "USB Tree View" for more information

Question / Help - Camera Limit? 3 work fine, 4th has problems

I got 5 video sources going through 3 USB inputs: 2 stereoscopic cameras and a video capture. My old Mac OAS can sense 5 cameras, (with both strereoscopic lenses as separate camera perspectives). I know my Mac OS can do 5 cameras, and was wondering if there was a way I can "chunk" the 2...
obsproject.com obsproject.com
USB Root Hub related
LeeHockHin said:
1) Download USB Tree View from https://www.softpedia.com/get/System/System-Info/USB-Device-Tree-Viewer.shtml
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aquawise

New Member
I'm having a ton of issues with cameras. I have three set up on a HP by3613dx laptop. 2 are in the superfast USB ports and one in a 4 port hub connected to the regular USB port. We've had numerous days when the cameras do not connect, so we shut down OBS 1, 2 or 3 times until it works. Yesterday 1 camera would not work at all. Previously the camera didn't work, but it did work ona previous camera source that hadn't been used for months.
I don't know if there's a way to add USB Root buses to the laptop or do something different like maybe moving the hub to one of the Super Speed USB ports. The hub also has 2 sound sources and my mouse.
 
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AaronD

Active Member
aquawise said:
I'm having a ton of issues with cameras. I have three set up on a HP by3613dx laptop. 2 are in the superfast USB ports and one in a 4 port hub connected to the regular USB port. We've had numerous days when the cameras do not connect, so we shut down OBS 1, 2 or 3 times until it works. Yesterday 1 camera would not work at all. Previously the camera didn't work, but it did work ona previous camera source that hadn't been used for months.
I don't know if there's a way to add USB Root buses to the laptop or do something different like maybe moving the hub to one of the Super Speed USB ports. The hub also has 2 sound sources and my mouse.
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If the hub is USB 2, then moving the hub to a USB 3 port won't help anything. You're still limited to USB 2 in total, and then that's shared across the entire hub. Sound can take a surprising amount, if you're doing multi-channel high-quality, and video takes even more.

Generally, USB 2 is good for exactly one video stream and nothing else at all. No hubs between the controller and that device, or if you have to use an internal hub, nothing else on that hub. Even so, Full-HD video (1920x1080p30) must still be compressed on the sending side, just to cram it through USB 2's fastest data rate, so you're still losing quality even with a dedicated connection.

You need a USB 3 hub, that actually *is* USB 3 and not a deceptive USB 2 thing with USB 3 connectors on it (those exist too), to get any benefit from using a USB 3 port.
 
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aquawise

New Member
Thanks, Aaron, the laptop has 2 SS USB 3.0 ports and a USB 1.0 port. I have a SABRENT 4 Port USB 3.0 Hub
USB 1.0, which I'll try swapping. I have 2 sound inputs on that hub: a camera and a mouse.
I'll try moving the hub to one of the 3.0 SS connections. Since a camera did work with the 1.0, it will probably work with any of the cameras. I've heard about Root hubs, but don't know how many there are and it appears you can't add any more. The laptop doesn't have a 34mm or 54mm slot for a card. I don't think pulling the DVD drive would help as it doesn't appear there's anything that can be added there to provide more USB hubs.
The laptop runs about 20% of CPU power when streaming. I had tried to add the 9 windowed multiview and noticed the CPU jump to over 50%.
 
R

R1CH

Forum Admin
Developer
Keep in mind a USB 3 hub won't help if the device itself is only USB 2. USB 3 and USB 2 are entirely separate systems electrically - a USB 3 port contains connectors for both USB 3 and USB 2 devices. A USB 2 device in a USB 3 hub will run over the USB 2 wiring all the way to the host, sharing the same USB 2 bandwidth limitations.
 
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AaronD

Active Member
R1CH said:
Keep in mind a USB 3 hub won't help if the device itself is only USB 2. ... A USB 2 device in a USB 3 hub will run over the USB 2 wiring all the way to the host, sharing the same USB 2 bandwidth limitations.
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Really?! My understanding was that, for each connection, the initial negotiation is always USB 2, and then they can decide to switch to the USB 3 wiring and leave the USB 2 wiring unused from then on. Thus, a hub shares the USB 3 rate (because it negotiated that with the host) with all downstream devices, even USB 2 ones or even USB 1. So a slower downstream device effectively gets its entire designed bandwidth to itself, even if there are more of them on the same fast hub. No?
 
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AaronD

Active Member
R1CH said:
A USB 2 device in a USB 3 hub will only run at USB 3 speeds if the hub itself has a translation chip (very unlikely as this is non-standards compliant and some devices simply won't function with one). You can read more about that at https://hackaday.com/2022/03/07/a-chip-to-address-the-fundamental-usb-3-0-deficiency/ and https://notabug.org/niconiconi/vl670/src/usb-b/README.md
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Wow! I would very much like to know what the engineers were smoking when they thought THAT was a good idea!
 
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aquawise

New Member
I was able to get the three cameras working today by pulling the 3.0 hb and moving to a SS 3.0 USB port. Then moved 1 camera to the USB 1.0 port and it worked. I removed some unneeded sources in my roughly 20 scenes. I check-boxed the deactivate camera win not shown, but that created a delay when switching scenes so I undid that choice.
Hopefully, they will start again Saturday night for the weekly YouTube church mass I stream.
 
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