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Krystian  
#1 Posted : Friday, October 9, 2020 11:33:57 PM(UTC)
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Hello all. I have three usb 3.0 cameras. Can I connect them to vMix? Camera parameters: 1920x1080px. I ask? Because I tried to connect two at the same time and the picture freezes after a while. Anyone have any idea how to solve this. Thanks for the help.
dmwkr  
#2 Posted : Saturday, October 10, 2020 12:27:54 AM(UTC)
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I think vMix advises to use USB capture devices for only one, maybe two cameras max (saw that in one of Tim's videos). If you use two, make sure to use separate, distant USB ports, eg. one port on the front, one port on the back of your PC.
vmixgreg  
#3 Posted : Saturday, October 10, 2020 12:47:13 AM(UTC)
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Hi Krystian,

Each system has a limitation on the amount of bandwidth it distributes to each of its USB 3.0 ports. Particularly when multiple USB 3.0 are in use at the same time with a USB webcam or USB capture device.
We have had users able to connect multiple webcams on their system, however, this is rare.

A Full HD source requires the full bandwidth of one USB 3.0 port.
All computers can do 1x HD USB webcam or capture device input reliably.
Some computers are capable of doing 2x HD USB webcam or capture device inputs at optimal quality.
Going beyond this most systems are not capable of doing 3 or more HD USB webcam or capture device inputs at optimal quality. Inputting more devices may result in quality issues, dropped frames, no signal or an error message. It is possible some systems might be able to do it. But this varies. There is no way to tell until you test it.

The issue is a combination of how each individual system handles the bandwidth sent to each of the USB 3.0 ports. As well as other contributing factors such as what other USB devices you also have plugged in.

Therefore, it is for this reason, when wanting to use multiple cameras (2 or more camera), we recommend using a normal camera connected to a capture card installed in the system for reliable and good quality results.
https://www.vmix.com/sof...are.aspx#capturehardware

If you already have multiple you can test with, then you can try it out on the system you wish to use it on and see how well it performs. Or you may need to work in SD resolution instead.


vMixGreg
thanks 2 users thanked vmixgreg for this useful post.
Krystian on 10/10/2020(UTC), AUSVIDE on 10/25/2020(UTC)
Krystian  
#4 Posted : Saturday, October 10, 2020 8:23:44 PM(UTC)
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Thank you for your prompt reply.

I am also considering:
Connecting several cameras to the Video Grabber 60fps 4K HDMI USB 3.0 1080P and further via USB 3.0 port to the computer. Will there still be a similar problem as above?

What do you think about it.

Thank you in advance for your answer.
RingsideReport  
#5 Posted : Monday, October 12, 2020 1:17:15 PM(UTC)
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We added a PCIExprss USB 3.x interface to get more USB bandwidth to get three cameras attached. Used it only once. Had a PTZ Optics Webcam as the main with 2 Logitech 920s. The first two were connected to the add-on USB. Didn't have a problem, but have not had a need for three cameras since then.
mjgraves  
#6 Posted : Tuesday, October 13, 2020 2:10:00 AM(UTC)
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This question just never goes away. I did a test using four webcams in 2019. https://www.mgraves.org/...ms-on-a-single-computer/

The result holds true even today and also for USB capture dongles. It's worth noting that some USB 3 capture dongle often don't support MJPEG encoding. Thus older USB2 capture dongles may have an advantage in some cases. Using MJPEG makes it much easier to manage the load and support multiple 1080p input streams.
PeteY  
#7 Posted : Friday, March 31, 2023 12:57:12 AM(UTC)
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I'm curious if there's been any updates that address this question or capability. I need to run a meeting with several people in the same room who will all be using their own PC's with external webcams and rather than having them dial into VMix call (which may be an issue on the corporate network) that it would be easier to have all the cameras come directly into my laptop with a hub. I think I'm potentially looking at 5 cameras with the final mix being fed out to a teams live event.

I did see a video about using VMix with MS Teams, but since there wasn't multiple users on the demo, its not clear to me if you can bring in multiple participants from a teams call. Any advice would be appreciated!
zenvideo  
#8 Posted : Friday, March 31, 2023 10:11:52 PM(UTC)
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Originally Posted by: PeteY Go to Quoted Post
I'm curious if there's been any updates that address this question or capability.

I suspect there's no "updates" because vMix itself has never had an issue with using multiple USB inputs. They're all just capture devices as far as vMix is concerned. The two real problems, over which vMix has no control, are:-

1) USB Bandwidth. Your PC may only have one USB host chip, even if it has multiple sockets, which will set the limit on the total number of USB capture devices/cameras that can be simultaneously connected. That bandwidth is also affected by the frame rate, resolution and format (compressed or uncompressed) of each USB source. As such, there's no simple answer to "how many?" can be connected, so unless you're able to do the necessary calculations, it's best just to test by adding one at a time (and it's always important to test anyway!). On some laptops with a combination of USB type A ports and USB3.2 type C ports there are two different host chips which should help to increase the available bandwidth, and on a decent desktop PC you can probably add a PCIe USB host card to give you more ports that don't share bandwidth with those built-in on the motherboard.

2) Device driver support for multiple units (of the same type). This is something specific to the brand/model of USB capture device or camera. In some cases, connecting multiple instances of a single device type does not result in each one having a unique entry in the devices listed by Windows, and therefore available to vMix, so vMix typically can only access the first one to be connected. Well designed devices might appear something like "USB CaptureBox", "USB CaptureBox (1)", "USB CaptureBox (2)", etc.
thanks 2 users thanked zenvideo for this useful post.
PeteY on 4/1/2023(UTC), mjgraves on 4/12/2023(UTC)
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