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USB video grabbers and computer speed

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#1 A. Viegas

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Posted 30 July 2014 - 04:50 PM

I sometimes run 2 or 3 USB 2.0 video grabbers to stream astro video but my desktop is sometimes painfully slow... Ok so maybe I should upgrade to a faster machine. Or is it a function of ram? I have a 3.4ghz 2 core win7 with 4gb of memory. It's about 5 years old. Should I buy a graphics card? Would that improve performance more than a beefier CPU and more memory???

Al

#2 Relativist

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Posted 30 July 2014 - 05:47 PM

Is it a desktop? If so what motherboard is it? Likely your best option is going quad core.

#3 Dwight J

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Posted 30 July 2014 - 06:39 PM

Get more RAM or a video card with more memory. Had similar issue and more RAM solved it.

#4 A. Viegas

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Posted 30 July 2014 - 08:13 PM

Which one? More RAM or a more serious video card? Either one will cost like $100-150... its a 2-core Intel motherboard, 3.4ghz i think. Cost of a new desktop that is rather powerful is like $600-800 so cost/benefit is not too clear, insofar as just upgrading. But I really dont want Windows 8!

Al

#5 Dwight J

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Posted 30 July 2014 - 08:35 PM

I just bought another gig of RAM for $34.95 off the net. Simple as plug and play. I too want to avoid Win8. Dismaying to read that Microsoft will discontinue support for Win7 in six months! I am keeping my XP machine going for the observatory as long as possible.

#6 Relativist

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Posted 30 July 2014 - 08:50 PM

Al, need to know more about the system. It sounds to me like an upgrade would be the best way to go, and it's probably CPU/RAM/USB card

#7 David Pavlich

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Posted 30 July 2014 - 09:08 PM

One thing...if your's is a 32 bit system, the maximum RAM that it can service is 4 gigs. Any RAM beyond that is wasted. If you do need a replacement, look for a refurbished 64 bit machine with Win7 and as many USB ports as you can find.

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#8 ccs_hello

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Posted 30 July 2014 - 10:04 PM

Al,

Please also check this CN post. By running the "USB connection chain" displaying software, you can identify how your "heavy bandwidth" consuming USB dongles are arranged.

I am not claiming USB bandwidth is the only bottleneck that will be THE issue; other components in your PC (CPU, memory, and hard drive) can also be issues as well.

By using that USB displaying tool, the goal is trying to spread the traffic to three different root hubs, if you can make it happen that way.
Three big bandwidth eaters (isochronous feeds at CCIR656 rate) competing over the same fixed sized pipe can be an issue.

Clear Skies!

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#9 Relativist

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Posted 30 July 2014 - 10:41 PM

ccs_hello has the right idea, that's why I mentioned the possibility of another USB card. Depending on your system, you likely have more than one USB root hub, spreading out the load is the first thing to do.

Hopefully your CPU can be swapped out for a quad core, that's always a good idea if one can be found inexpensively and extends the life of a system. The GPU can be upgraded and you can put in a solid state drive.

#10 RandyC

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Posted 31 July 2014 - 01:14 PM

A quad core is nice because you are doing so many things at once, ie guiding, controlling the camera, planetarium software, Internet. I searched for a fast machine with a lot of expansion slots. This was for flexibility in adding frame grabber cards, including an HDMI in-port. I ended up getting an HP Business Desktop Pro (not the SFF) 6300 because it had 4 expansion slots. None of the gaming machines have any expansion slots.
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#11 A. Viegas

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Posted 31 July 2014 - 09:43 PM

I am running 2 frame grabbers on one USB 2.0 long repeater chain and another on another long run USB repeater. I find the system handles this load ok until I use splitcam to broadcast on NSN.. Then it just hangs and slows down huge... So I think it's the splitcam and NSN that crushes the speed and responsiveness... Is this a GPU or a CPU or a RAM problem you think?

Al

#12 Dwight J

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Posted 31 July 2014 - 10:15 PM

When Miloslickmoved to version 2.0 etc my old XP with one Gig of RAM ran extremely slow. That's when I upgraded it to 2 gigs. Runs it now on NSN using Webcamax.

#13 RandyC

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Posted 31 July 2014 - 11:44 PM

I am running 2 frame grabbers on one USB 2.0 long repeater chain and another on another long run USB repeater. I find the system handles this load ok until I use splitcam to broadcast on NSN.. Then it just hangs and slows down huge... So I think it's the splitcam and NSN that crushes the speed and responsiveness... Is this a GPU or a CPU or a RAM problem you think?

Al

Al, I think a video card will help you a lot. As long as you have an open slot, you could try one with 1gb RAM. Nothing fancy is needed because it's much less intensive than gaming, a $50 one is fine. At some point, all the Windows updates and spam overwhelm an older system, no matter what the CPU speed, RAM, etc. I also only use Miloslick 1.x because I couldn't switch between frame grabbers without shutting it down.

#14 A. Viegas

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Posted 01 August 2014 - 04:43 PM

Thanks for the advice Randy. Yes I have that same annoying problem with Miloslick crashing every time i switch grabbers. I will shop for a basic 1GB PCI card.

Al

#15 Charles Copeland

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Posted 11 August 2014 - 01:34 PM

I think the problem is the PC is having to do the mpeg encoding on raw video and its eating all the bandwidth.  You can buy a box that does the mpeg encoding for you and will reduce loading on PC over 90%.  The WinTV-HVR-1955 is one box than can encode mpeg.  Its meant for cable/antenna TV, but should work on a video camera.

http://www.hauppauge...ta_hvr1955.html


Edited by Charles Copeland, 11 August 2014 - 01:34 PM.


#16 Relativist

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Posted 11 August 2014 - 02:31 PM

That is true Charles, but if I understand correctly most are trying to get the best picture quality so encoding into a compressed format goes against that. Having said that, if there are ancillary channels that quality isn't as important then this would be a good solution. For example, I'm thinking of putting one of those LN300 based astro cams on my Celestron Firstscope as a finder, in such a case I don't really care about quality but mostly sensitivity is what I'm looking for.








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