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chrislcarey
02-04-2001, 02:18 PM
When capturing from VCR I get annoying jumps and jittery frames, like the video signals aren't syncing up right. These intermitant problems seem to be worse when capturing video recorded in the SP mode. LP and SLP mode works a bit better. (And of course all the home videos I'm trying to edit were shot in SP!)

The video I capture is 320x240, at 30 fps. When I play it back on the Quicktime player it drops to 28, and 24 at times. When I play the videotape directly to my TV screen it looks perfect.

What's going on here? Any ideas?

I'm using a MilesUW2 and 18GB IBM drive formatted with Softraid for capture, on a PTP, 400 mhz XLR8 card, 304 RAM.

PENDRAGON18
02-04-2001, 04:06 PM
I assume your 400Mhz XLR8 card is a G3. I would try using VM on and off. With VM on the two main settings are 1MB over physical RAM and 2x physical RAM. You should also try setting your disk cache to 1MB or less. SP is normally a higher quailty. I assume your capture settings are the same even though you get better results with SLP/LP settings on the VCR. That would indicate to me an issue with the VCR or maybe VCR/Capture card issue. NTSC is NTSC - 60fps and about 500 horizontal lines (probably about 200 to 300 with SP mode on VHS) - so I do not see how a lower quality, slower speed on the VCR could affect capture quality.

Do you use the 18G drive for everything?
Is it partitioned?
If it is only a signle drive you might want to try Apple's drive setup.

Also, make sure you have it set to uncompressed capture. This seems to work best for eme - even just setting audio compression while capturing AV can cause dropped frames. Uncompressed datarate is 3.5MB/s - at my S900G3/500 seems to handle this well (miles U2W).

magician
02-05-2001, 01:30 AM
make sure you have enough memory allocated to the capture application, ensure you are running QT4.1.2 or later, and finally, ensure that you have updated the Miles2 firmware to 1.06b and SoftRAID to 2.2.2. You may want to also try slowing sync rates on the Miles2 per the guidance on our Initio page.

tekcan
02-05-2001, 03:37 PM
Important question: can you see the jumpiness (or off-tracking) on the screen in premiere or your video software even before you capture, (while you preview?)?
If you do, I have the very same problem, it only effects one SP speed tape, I even switched out VCR's (one had auto tracking, one manual)and yet the problem still persists. I switched all cables and tried every concievable setting the card has to offer.
All other captures are fine...even up to 640X480
I have a PTP200, 196MB Ram, exclaimVR 128.
Funny how I was just having this problem last night! It only effects one tape so far, (but an important one!)
Tonight I'm going to try and tape the effected tape to a new tape and see if it clears up. I hadn't made the connection between tape speed and the "effect" yet, was thinking it was because this tape had had alot of play, and was perhaps worn beyond use.
Keep me posted, I'll let you know what I try. Maybe we are just missing something somewhere...
Terri
I did want to add that other than this tape, my VR128 works great! I have captured lots of video and have had some playback stuttering, but thought it would be resolved when I purchased my G3 upgrade. Makes ya think!

[This message has been edited by tekcan (edited 05 February 2001).]

tekcan
02-05-2001, 09:25 PM
I have done some further testing..
1. Tried playing jumpy video in two different VCRS- one manual tracking, other auto tracking. No difference, still jumpy.

2. Changed out cables, no difference, still jumpy.

3. Tried other videos, including 8 camcorder tape in adapter, direct recording from camcorder, full sized video tape recorded from old 8 sony camcorder, (1985 handi-cam), and several video store movies. None of them had the jitters, just the original jitter tape, (that was recorded by a friends camcorder, then a copy made for me) continued to show effect.(shows fine on TV, just like yours).

4. Tried retaping jitter tape to new tape, just because I want to be thorough, taped at SP, EP & SLP. When replayed, had jitters at all speeds.

Conclusions:
1)It's not the ATI capture card, everything I throw at it looks fine, except this one tape.

2)Could be the tape itself. Was it, and others you are having problems with, exposed to weather or a magnetic field? Are you using fresh tapes? (not retaping?) Are they all the same brand?

3)Could be the camcorder you are using. Try capturing a store tape, like Moby Dick or a rental. Do they look OK? Try capturing directly from you camcorder to your card, hook it up to your card and hit record, dance around, do you jitter? Borrow a friends camcorder, do the same tests.

4) Could be your VCR.Try capturing directly from you camcorder to your card, or try another VCR.

In my case, either it is a bad tape, or my friends camcorder,VCR or cables are bad.Everything I have checks out fine.
Try these tests yourself, and you'll pinpoint your problem.
I even went so far as to re-record a copy of a movie I made and output to tape. No jitters. Looked great.Just the tape my friend recorded and made a copy of for me exhibited this problem.

chrislcarey
02-06-2001, 03:36 AM
Thanks, everyone, for the suggestions. I did some further testing and found that if I record the jumpy VHS tape to a digital camcorder, then feed the copy into the VR128 it looks just perfect and captures cleanly. How odd! I had also tried several different VCRs, but found them all to playback with the glitches.

Last night after copying to camcorder I successfully completed capturing & editing 1/4 of an 8 hour vacation collection I hadn't touched since 1987!! Sliced and diced the two hour footage into a very watchable 12 minutes or so.

This is so much fun! Exactly what I've been dreaming of being able to do for years. Thanks for the help!

magician
02-06-2001, 06:34 AM
it's incredible that you can do that with a card that retailed for a little more than $200!

AND you can use it to watch Howard Stern on E!

definitely a cool card. We're preparing to post the replacement for it, the ATI USB xTV.

http://www.macgurus.com/graphics/xtv_pod.gif

http://macgurus.com/infopop/emoticons/icon_biggrin.gif

tekcan
02-06-2001, 10:56 AM
Thanks Chris for getting back to us, will try your method tonight, I had given up on being able to help this guy save his Sturgis party video!

professor
02-07-2001, 01:58 AM
Try this,
instead of recording to the camcorder and then to the card,
go ahead and try recording throug the camcorder into the card, kind of like a passthrough. Maybe it will sync up that way and save you some time.