Safe way to capture DV video through while using the computer w/o dropping frames? at

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Old July 8th, 2009, 05:18 PM   #1
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Safe way to capture DV video through while using the computer w/o dropping frames?

Having used MiniDV video cameras for years and capturing/printing many hours of tape via firewire, I've always had to watch out for dropped frames. It seems a sure-fire way to avoid dropping frames on any somewhat modern system is to let it idle and to close any unnecessary programs.

I have a fairly fast laptop (Pentium M, 2.1 GHz, 1 GB RAM, fast 360 GB HD) running Windows XP. Letting the computer idle while capturing works fine, but I'm trying to figure out a safe way to use the computer while capturing without risking any dropped frames.

I have tried Sonic Foundry Video Capture (old version of Sony Vegas Video Capture), WinDV, and Exsate DV Capture Live. They seem to all work just fine if I'm not using the computer, yet all three of them will drop at different times if I open up Word, use Firefox, open up Thunderbird -- stuff that's not too taxing but is definitely more than idling.

Anyway, I'm looking for ideas for a way to safely use the computer, even in a limited fashion, while capturing. The most important goal is to not drop frames, obviously, but I would love to be able to use the computer while it's capturing.

So... any ideas? Perhaps a certain DV capture program that does a better job? Or maybe changing the video capture process priority to high? Or... anything?

If there were any way to block out a chunk of the computer's resources for capturing, that would be great. But I don't think there is any way to do that, aside from the process priority.

I'd love to hear some ideas! Thanks for reading.

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Old July 8th, 2009, 06:22 PM   #2
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There is no way. Video capture will tie up your computer for the time that it takes.

It's not a software issue but a hardware issue. Those dropped frames come from either a hard drive not keeping up with the transfer rate, or from interruptions to the data flow as other software accesses the HDD during launch.

Best thing you can do in terms of making use of the time while your computer is ingesting video? Clean the office, phone a client or make coffee.

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Old July 8th, 2009, 06:43 PM   #3
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Or buy a CHEAP computer for other purposes such as checking in on DVInfo and Facebook.
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Old July 8th, 2009, 08:47 PM   #4
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Welcome to the real (hardware) world, Neo.

Most of the time multitasking works just fine because things can wait if the machine gets a little busy. Excel, Word, Web Browser updating, whatever.

When you're capturing, the data is coming in that FireWire port at ~3.2 MB/sec.
No ifs. No ands. No buts.

And when you start trying to do something else, grabbing that data and getting it to the hard drive in an uninterrupted realtime fashion just goes all to hell.

Because it won't wait. No ifs. No ands. No buts.

One other thing. That Pentium M, 2.1 GHz, 1 GB RAM, fast 360 GB HD machine is NOT fast in the current context. I have a Pentium IV 3.0 GHz, 2 GB RAM, 160 GB HD and that's not fast in the current context. More like five year old tech at this point. But I do use it to capture either DV or HDV via FireWire. With no hiccups. But then, it's not doing anything else. I'm busy shooting.
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Old July 10th, 2009, 09:26 PM   #5
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Use an external USB2.0 hard drive for capture (avoid FireWire ones so that you don't run into clashes with the camcorder - there's no practical difference in performance for DV capture).

The primary issue is that your hard drive has to thrash to and fro between the capture file, launching a program such as Word and accessing the documents. It can take the equivalent of a couple of frames for the drive's heads to find the required locations.

I can happily capture to an external drive with my laptop while doing email, surfing and even compiling code. Also turn off any power saving options, virus scanners, automatic searches etc. The DV data rate ain't that demanding - my old 600MHz PIII worked just dandily using its internal drive. Finally, you can use Task Manager to raise the priority of the capture software though I have never really needed to (but be sure to understand the potential impact on the system).
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Old July 15th, 2009, 06:38 PM   #6
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I don't quite know what sort of interface card you would need, I've never seen anything other than a PCMCIA 2 FireWire adapter, but those little Atom based netbooks are reasonably cheap and more than up to the task of capturing DV streams.

Heck, I wish my Acer One was ready to go with that, I still use a larger Toshiba P4 3.06ghz for portable live-DV capture. I also record to tape at the same time, just to be sure.

My rule of thumb on any computer, is when you are capturing (Firewire, USB, PCI slot, whatever), you don't use that system for anything else. You leave the monitor on so you can check out it's progress, but that is it. No surfing, no nothing. Screen blanker is disabled, and I'm not doing any SETI tasks in the background.

I used to DJ in the country for socials, and my partner was always playing poker on the same machine the tunes were coming off of. This was back when 750mhz was fast for a smaller system.

Just because you might have the newest Quad Core i7 , the capture (or.. lets call it what it is.. recording) process is to be left to do it's thing.

Explain to a client why there's missing footage because you were IM'ing people.
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Old July 16th, 2009, 08:05 PM   #7
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I have multiple PCs in my edit suite, and am still in the habit of "go make a coffee" when capturing is on. *lol*

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Old July 17th, 2009, 08:29 AM   #8
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Thanks for your insight, everybody.

To give a bit of an update...

Sadly, it sounds as if no computer is truly impervious to dropping frames while capturing. That said, with a little bit of testing, I found out that not all video capture programs are created equally. One in particular, Excase DV Capture Live, seems to have a much higher tolerance for other CPU/hard drive activity than the Vegas Video Capture program I had been using.

Both programs did okay when the computer was idling, but the Video Capture program would drop frames much more quickly with any other computer activity.

My best results came when I captured to a secondary hard drive. The second HDD, combined with using Excase DV Capture Live, had some pretty impressive results. I could do about anything within reason on the computer and not have dropped frames.

Since it's obviously crucial to never drop frames, I'm going to do a little more experimenting to get an idea of what I can safely do on the computer without ever dropping a frame.

Bottom line: Using a different program (such as Excase), your computer may have a much higher tolerance for activity before it starts dropping frames. I also experimented with WinDV, but I didn't have much success with that program. It would inexplicably start dropping hundreds of frames within 10 or 20 seconds.

Hope this info helps somebody! Dropping frames may always be a risk, but using the right hardware and software might greatly reduce the chance of dropped frames.
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