Why so many dropped frames?

Hammer schrieb am 03.06.2002 um 18:06 Uhr
It's actually a very small percentage of the total. However, I don't recall any of the other products I tried dropping frames. I looked at the dropped frame guide but there really isn't anything there to help(enable DMA). Seems like the common advise is buy another drive and capture directly to that drive. I'm skeptical of that advise though. I have P4 2.4ghz/512m PC800 ram/ and 7200rpm 80GB hard drive. I find it hard to believe that there aren't enough resources to capture without dropping frames. To those of you who did install a second drive, did the dropped frames go away or just reduce? For example I captured about an hour of video and had 391 dropped frames. Is this high or normal?

Kommentare

hendo schrieb am 03.06.2002 um 19:18 Uhr
Hi
The only time I ever got dropped frames, was when I forgot to turn of the programes that where running in the background, I should have known better. The other thing that I noticed was that if the PC has been running for a few hours, it was always better to reboot the PC, before capture in case there was any memory leak. At the time my setup was Athlon 1200, 256 DDr mem, 13 gig ata 33 HD. Your system should behave perfectly.

Andrew
Ehemaliger User schrieb am 03.06.2002 um 19:21 Uhr
Have you tried other source tapes, sometimes the tape can cause dropped frames?

What other products did you try that did not cause dropped frames?

Dave T2
kcarroll schrieb am 03.06.2002 um 19:31 Uhr
Hammer;

When I added a dedicated capture drive the number of dropped frames that were reported did, on average, seem to go down. The reports did not go away completely. I don't think, however, that this is simply a hardware issue.

In the course of working with VF, I have become convinced that the algorithm that VF uses to document dropped frames is either faulty, or at the very least, easily confused. On several occasions I have seen dropped frame counts that were clearly wrong. In one instance I got a report of 1,478,724 dropped frames in a one hour capture. This is clearly impossible, as that number of frames works out to be 13.7 hours of video at 30 frames per second! When this movie was rendered, there was no indication of lost data. It played fine.

Most of the source video I work with was taken under very difficult conditions, with hand held cameras, and multiple starts and stops. This results in rather "jerky" source video. I suspect that the "Dropped Frame Detection" algorithm within the VF program sees these breaks in continuity as dropped frames, and reports them as such, even though there has been no real data drop-out.

I have also noticed that I typically see no dropped frames when capturing from a regular VHS VCR, while I have learned to expect them when I'm capturing from a 8mm camcorder tape. This tends to reinforce my suspicion that the way the souce is recorded constitutes part of the problem.

For my own projects, I have become very tolerant. Unless I can see or hear indications of lost data in my final product, I don't even worry about the Dropped Frame Report.

kcarroll
Chienworks schrieb am 03.06.2002 um 19:35 Uhr
391 isn't abnormally high, but it's not great either. I run an 866 P3 and average 0 dropped frames per hour consistently. I think the key is to make sure there are no other programs or unnecessary processes running in the background.

You didn't specify your capture method. I get zero-dropped-frames captures with firewire all the time. If i try capturing analog with my ATI Rage card, i'll occasionally drop a few.
Hammer schrieb am 03.06.2002 um 19:53 Uhr
Thanks for the feedback. I capture through a firewire card. Most of what I have done has been analog source, but I tape with my miniDV first, then capture straight from it. This is just for convience, I have done some capturing using the pass through functionality but I didn't notice any real difference in reported frame drops. As for which programs I have tried that don't report drop frames, VW4 and video studio 6. Both of these captured without reporting dropped frames. I don't use VW4 because of audio issues, and I just decided to go with VF over VS6 because of the active support community. It seemed like a good product but the support forum was dead. I'm running XP home edition and there are a number of processes active, but that's typical for a multitasking OS. I don't have any active applicationes and there is nothing in the system tray accept for Norton anti-virus which is disabled during VF sessions.
Frenchy schrieb am 03.06.2002 um 20:02 Uhr
I capture D8 via firewire to my P3-600 running W98SE with a dedicated 40GB 7200 RPM media-only HD, and have only exprienced dropped frames when I forgot to turn off Norton, EZCD Creator, task manager and other unnecessarry programs. In an inadverdent experiment last week, I batch captured a couple of two or three minute clips, and had a (surprising) 20 or 30 dropped frames. Then realized I had Norton and the other above programs running in background. Turned them off, and successfully recaptured, with no dropped frames. Also, if I have been running multiple programs, etc, I usually re-boot prior to capture. This usually frees up 89-93% of system resources, depending on solar flares, and other esoteric cicumstances...

Frenchy