USB grabbers with USB3, bandwidth issue maybe solved?

[TuxEvil]

Hi, I was reading many post about the bandwidth problem connecting multiples usb grabbers to the same USB hub (USB 2.0 480Mbps), could this problem be solved in the new version of USB 3 (5Gbps)?

If this interface could handle that bandwidth and we use USB2 grabbers, could mean that connecting 10 devices will work as always do 1 USB2 per usb hub?

Some one have tried this out?

I found here in Argentina an USB grabber from Avermedia (DVD Ezmaker7) and the seller told me that he connect 2 of it and works fine, no drivers conflict and could be a cheap solucion for multiple inputs requirements.

[Mike]

USB2 works for most solutions, the problem is in the controller not being able to handle more than one device if that device already eats up more than half of the available bandwidth. I can hook up 4 USB2 devices to one controller as long as I make sure the device uses less than 25% of available bandwidth, which can easily be achieved by selecting a very low video resolution.

I have not read up on USB3 nor run any tests with it, so do not know what happens with bandwidth if you hookup a USB2 device to a USB3 controller.

[zenvideo]

Hi, I was reading many post about the bandwidth problem connecting multiples usb grabbers to the same USB hub (USB 2.0 480Mbps), could this problem be solved in the new version of USB 3 (5Gbps)?

If this interface could handle that bandwidth and we use USB2 grabbers, could mean that connecting 10 devices will work as always do 1 USB2 per usb hub?

I don't think that would work. When you connect USB2 devices to a USB3 port/hub, AFAIK it simply slows down to USB2 speed. That's what they mean by "backward compatible" - a USB3 port will emulate a USB2 port by working in exactly the same (slower) way.

To get more bandwidth for multiple USB grabbers, I suspect the grabbers would all have to be USB3 devices working on a USB3 hub in order to get the greater speed.

[Mike]

This is why I said that I am not sure what happens if you connect the two, i.e. if speed is the only difference then I can imagine someone makes an intelligent hub that has a master connection that is USB3, and all others are either USB2 or switch. The hub converts everything to USB3 et voila. Maybe something like that already exists? Imagine the impact this will have for, at least, internet streaming where reasonable SD is more than enough. Easily hook up a bunch of cameras to a laptop. I'd almost get my USB grabbers out of the archive again :)

[Monoscopio]

Found myself a $60 Superspeed USB hub and going to try this tomorrow :) Just need to dig out the usb grabbers :)
http://www.usr.com/products/peripherals/peripherals-product.asp?sku=USR8400

[zenvideo]

Well, I think I was wrong - in quite a big way! Some more research has revealed that the difference between USB2 & 3 is much bigger than that between USB1 & 2. A USB3 connection has additional electrical connections (inside the same size USB connector) as well as a different protocol. When you connect a USB2 device to a USB3 socket it simply uses the (old) USB1/2 electrical connections and not any of the USB3 enhancements. As far as I can see, a USB3 hub will only deal with USB2 devices by connecting them down the embedded USB2 cable connection, and not by some sort of smart conversion to share the USB3 bandwidth on the dedicated USB3 signal cores.

[Mike]

Interesting! It says Each port detects native USB speed and transfers data at the maximum rate for each port so this could mean it converts speeds as I was hoping for. This small detail can revolutionize mobile internet studios. You don't happen to have a laptop with USB 3.0 port? If so, run a camera while you're testing as you'll be making history :)

[Rafal Oramus]

This small detail can revolutionize mobile internet studios. You don't happen to have a laptop with USB 3.0 port?
I'm so surprised, that nobody produces 4-input SD quality frame grabber for USB 3.0...

[Sinc747]

Interesting article on USB3 and cameras here (http://www.ptgrey.com/news/pressreleases/details.asp?articleID=353).

[TuxEvil]

Interesting article on USB3 and cameras here (http://www.ptgrey.com/news/pressreleases/details.asp?articleID=353).

and interesting products ;)
USB3 Camera
http://www.ptgrey.com/products/flea3_usb3/flea3_usb3_camera.asp

how many we could connect at once?

someone tried several blackmagic shuttle?

[Rafal Oramus]

Sebastian, I thought we are talking about connecting multiple cameras via usb 3.0, by usb 3.0's advantage in speed over usb 2.0. It's not about higher resolution, image quality and so on...

There is nothing interesting in this camera, from this threads point of view.

There are topics about blackmagic shuttle on this forum, just search.

[Monoscopio]

No luck yet... USB3 drivers dont want to play along...

[Mike]

I am afraid the cheaper hubs will simply use the dual bus system Martin describes. What we need is a hub that uses controllers for each port, which then serializes everything into one USB 3.0 stream. I'm sure they will come to market, or already exist, the problem is to distinguish them from the dual bus models.

[weconverse]

I'v managed to get four (4) Microsoft Lifecam Cinemas working on one PC (i7 2600K, 1600 Mhz RAM on Gigabyte P67...UD7 MoBo). Is OK at 1024x576 25 fps, but too stressful for the machine in my view. I can't do more than a couple of VE's while recording and streaming (in a lower res).

[Mike]

Not sure I understand your post Richard. What hub did you use? Note to test it simple only use camera modules.

[weconverse]

Well, I just wanted to say it is possible. I used only the USB ports on the backplane of the GA-P67A-UD7-B3 motherboard:


Chipset:
- Up to 8 USB 2.0/1.1 ports (4 on the back panel, including 2 eSATA/USB Combo, 4 via the USB brackets connected to the internal USB headers)

2 x Renesas D720200 chips and 2 x VLI VL810 hubs:
- Up to 10 USB 3.0/2.0 ports (6 on the back panel, 4 via the USB brackets connected to the internal USB headers)
* The USB 2.0 signals of the 6 USB 3.0/2.0 ports on the back panel are from the Chipset.


I have used the Lifecams to produce first two shows at www.spelbildning.se (http://www.spelbildning.se) (terrible light conditions, that's the main problem ; ). What I noticed was that if I instead used the same number of camera modules, but replaced all USB cams with analog ports on the Datapath Vision SD4+1 the stress on the CPU went from around 80% to perhaps 50% (writing this from memory, I have since reconfigured that PC).

(sidenote, I saw some reports on the web that it was possible to use this motherboard with Blackmagic's Shuttle using the NEC USB3 drivers supplied with the MoBo).

[Mike]

Mm.. I think this is another example of you not reading the thread before posting? We know it is possible, just not if you only have one USB controller. That is why we discuss USB 3.0 here, see subject, and more specifically what happens if you hook up 2.0 devices to a 3.0 hub.

I'll move this to the Hardware section as this is turning out to be an interesting thread. "Hunting for that intelligent hub."

[weconverse]

Rather, I was not assuming that the topic was only about *external* hubs. Actually, the title reads "USB3, bandwidth issue". While reading the initial message I did not get the impression that Sebastian's concern was a particular type of hub, rather the bandwidh problem. (see attached list of different internal "hubs").

As I personally have had various experiences with multiple USB grabbers and USB webcams on different PC:s with different (ext/int) hubs/controllers I found it useful to point out one relatively successful combo.

Sorry if I confused anyone. And I do apologize in advance if I in the future mis-reads something in the Forum, where the number of topics/message grows fast, while my main business is to produce livecasts for our customers. But I am happy to help at sometimes, and for the opportunity to learn here together with others.

From a very sunny quayside in Stockolm

[Mike]

Lacking any USB3 video capture devices, except the dreaded Shuttle, for now we're forced to use USB2. Hence the research into how to use the advantages of USB3 for these devices. Hence the hub.

PS: Cannot apologize in advance, I will continue to remind you to read threads before posting ;)

So.. Daniel, you are having problems with the hub in general, or only when you try to hookup USB2 devices?

[weconverse]

I should perphaps clarify that I do believe (but do not know) that I managed to use all 4 webcams (same model=driver) due to the fact that there are USB3 hubs/buses on the motherboard.

[Monoscopio]

Rather the usb-port itself and the mobo drivers for it. Still have hope for the hub... Will try to solve this tomorrow, at a hockey arena in Uppsala at the moment.

[zenvideo]

Well, I just wanted to say it is possible. I used only the USB ports on the backplane of the GA-P67A-UD7-B3 motherboard:

2 x Renesas D720200 chips and 2 x VLI VL810 hubs:

Here's a link to the info about the VIA VL810 USB3 hub http://www.via-labs.com/en/products/vl810/index.jsp

From reading the text and looking at the block diagram, there's no definitive evidence that this device is translating between USB2 and USB3 (and therefore sharing USB3 bandwidth between multiple USB2 devices), rather than merely running USB2 and USB3 connections in parallel, and routing the device connections accordingly.

Also, I noticed in Richard's Device Manager list a Fresco Logic FL1000, which I think is another USB3 host controller. So in total I can see there would be four USB controllers on the system, one USB2 in the main Intel P67 chipset, the two USB3 Renesas chips plus the FL1000.

Certainly that Gigabyte motherboard looks like a good choice if you need lots of USB2 & 3 controllers and ports built in (even if it doesn't answer our question about aggregating USB2 bandwidth over USB3).

[weconverse]

Geee, I knew I shouldn't have taken the short cut, eg dumping an image from my laptop. So, I updated my message with a list of USB units that actually are on the motherboard I exemplified with.

IN OTHER WORDS, there is no Fresco... thing on the Gigabyte motherboard (but in my Asus U36S SD laptop).

Sorry Martin (and others) - I'll be better...