messed-up frames on DV capture

[john_gregg]

Hi all.

I'm new to the DV transfer/capture thing. I'm trying to transfer some shots I made using the firewire connection from my Canon ZR40. Of the short captures I've done (a few minutes max), on average every few seconds there's an audible scratch or pop, along with a screwed up picture. I've attached a screenshot so you can see what I mean.




I've had the same experience with several editing/capture programs (MovieXone 4, Vegas Video 3, Ulead Video Studio 5.) My tapes are NTSC 720x480, 29.97 fps. When I play the tapes and view them either on a TV, the LCD, or the viewfinder, things are fine. Sometimes the capture software will say a frame or two was dropped. When the capture software allows it, I've tried turning off the simultaneous preview feature.

My hardware is a Celeron 900, 512MB RAM, IBM 75GXP, and Koutech firewire card. OS is Windows 2000. The capture is being saved to the same drive as the OS (it's the only one I have) though to a different partition. There's around 10GB free on the capture partition.

I'd appreciate some suggestions.

thanks

john

[Nielchiano]

I'm not an DV expert, but I think I might help you just a little:

the screenshot seems to have some MPEG trouble: parts are fine (I count 5 (big) blocks wich are OK). Some parts contain the right image but at the wrong spot (most other blocks) and some (small) blocks are green-ish.

I saw a look-a-like problem with a DV camera I borrowed for our school-trip to Barcelona. The problem there was that the tape (miniDV) itself was not clean... someone (and I know who, but that doesn't matter here) wondered what a DV tape looked like and grabes it with his "dirty" hand... After some cleaning it played back fine. (you might try it, clean the part of the tape where the dropping occures)

However, since the video plays fine directly from the camera (either LCD, TV-out or whatever) but not on the computer. The problem should be in the DV-circuit or futher (read: computer-cards/soft).
Your software tells that frames have been dropped: that might explain it. Your machine is powerfull enough, since I captured DV on a 733MHz PIII. Maybe try to shut down ALL programs before capturing. Also do a defragmentation of your hard-drive (the capture partition first, then (if you have time) the windows one).

Hope this helps,
Nielchiano

[john_gregg]

SOLVED

I tried a number of things before solving this problem. First, I defragged the capture partition but it made no difference. Next I considered changing IRQs but it's a pain in Windows 2000 so I skipped it. Finally, since I had read that reordering PCI cards might have an effect, I did that. I removed all PCI cards with the Device Manager (Koutech Firewire, D-Link USB, Creative SB Live, Intel NIC.) Then I shut down the machine and physically removed the cards. I restarted and shut down again. Then I installed one card at a time starting with the firewire card. I installed it in the 2nd slot, counting from the side closest to the AGP slot ("the top") on my Tyan Trinity board. I restarted and tried the capture. Bingo. I then installed one card at a time and tested capture each time. The order was firewire, usb, nic, and sound in PCI slots 2, 4, 5, and 6. Now things work great.

john

[Carlibra]

I would also suggest getting a dedicated disk drive for your captures that runs at 7200 rpm or faster.