A cure for a bad case of dropped frames?

blk_diesel wrote on 2/12/2006, 6:20 PM
Is there anything I can do to reduce dropped frames from an analog to digital capture? This was the first time I used V6 with my ADVC-100 to capture video from a VHS tape so I was surprised when I captured a 2 hour concert and had 150 dropped frames!!! I don't remember ever getting this many before.

What's the cure? Do I just have to live with it

Comments

RalphM wrote on 2/12/2006, 6:37 PM
Defrag HDD?
craftech wrote on 2/12/2006, 6:52 PM
Despite it's age the support item entitled How to ensure successful DV Capture and Print to Tape is still very helpful.

Turn off the preview window and eliminate running processes that are unnecessary. Not an easy accomplishment with Windows XP but worth the effort.

John
Chienworks wrote on 2/12/2006, 6:58 PM
Setting the priority to "Above Normal" on the VidCap process pretty much eliminates dropped frames for me. I can still edit video, render, play music, word process, edit photos, surf the web, and play solitaire simultaneously* on my PC and still not drop frames.

*Me ADD? Never! How could you even suspect such a .... hey, there's a duck!
johnmeyer wrote on 2/12/2006, 7:46 PM
You need to determine whether your dropped frames have to do with your capture setup, or whether they are due to the analog portion of your capture.

Therefore, the most important question is: If you unplug the cable from your ADVC-100, and plug it into a DV cam, and then capture 20 minutes of video, do you get any dropped frames?? If you get even one, then something is wrong with your computer and how it is set up for capture.

Second, plus your ADVC-100 back in, and feed it the composite signal from your cable box or satellite box (i.e., a nice clean signal). Then capture 20 minutes of video through your ADVC-100. Do you get any dropped frames? If you didn't get any in the first step above, but now you DO get dropped frames, then something is wrong with your ADVC-100. I would then try substituting your DV camera for the ADVC-100, and then capture the video using the camera's "pass-through" and see what happens.

Finally, if everything is OK (no dropped frames) in the first two steps, then that says the problem is with the VCR or the tape. Some really lousy tapes have serious playback problems. Do you see any flagging or breakup or other signs that the VCR is having a problem? Is this a 6-hour EP recording or a 2-hour SP recording? The 6-hour tapes can cause problems, including dropped frames.

If the problem is your VCR, then the solution is to use a better VCR. If you are already using a good VCR, then you might look at the controls. You should ALWAYS use the "Edit" or "Tape Dub" mode, which defeats a lot of the signal processing circuitry (which is designed to "smooth" the video, but loses LOTS of detail when you capture). Some VCRs have a mode designed to help re-sync EP tapes that don't play well. Read your manual to find out what you have. You might also try manually adjusting the tracking control.

[Edited for clarity.]
blk_diesel wrote on 2/13/2006, 7:17 AM
Thanks for the replies. I have never had a problem with dropped frames when capturing from my camera. I did noticed that the dropped frames came in bunches; for example, I would get like 10-20 at 1 area of the tape.

The tape is maybe 4 years old but has been stored in a dry place. The source on the tape is from a 2 generation tape which is about 10 years old.

Come to think of it, I do need to defrag. I will try to identify what hard ware is causing the problem. Thanks again for the input.
Chienworks wrote on 2/13/2006, 8:06 AM
Don't bother defragging. It's almost certain not to help. It's just a waste of time and extra wear on the drive.
Lili wrote on 2/13/2006, 10:11 AM
Whenever I get dropped frames I notice that they come IN BETWEEN two diiferent clips on the tape i.e. when I have shut off the camera and restarted (usually). I know that dropped frames are supposed to be considered a big no, no, however since 1 second equals 29 frames, when I have 80 dropped frames in a one-hour video and they occur in between clips, i just don't consider that a big problem. It is not noticeable at all in the final product.

I would watch the entire capture to see where frames dropped, and that's how I discovered where they were happening.
johnmeyer wrote on 2/13/2006, 11:10 AM
As Kelly (Chienworks) says, defrag won't help and in addition to the downsides he mentions, I'll ad that it consumes your time chasing a wild goose, rather than fixing the problem.

You do need to go through the steps I mentioned in my last post (which I just edited to hopefully make it a little clearer).

From you last reply, it sounds like the computer capture of DV material from you camera works fine with no drops (you should NEVER drop a frame when capturing DV tapes). My interpretation of what you said is that the dropped frames come in bunches at certain scene transitions. If that is the case, this is definitely a problem with a weak signal. Some top-quality ($500 and up) VCRs have circuitry to help better track weak tapes. Also, see my previous comments about reading your VCR user manual VERY thoroughly to see if your VCR has settings to "improve" 6-hour tape playback. Finally, I will re-iterate what I said about trying to manually adjust the tracking controls during playback to get a more stable picture. If your picture has flagging, tracking noise, breakups, or other problems of that sort, you probably will experience dropped frames.
blk_diesel wrote on 2/16/2006, 9:11 PM
Guys, I solved the problem. It seems that a McAfee function was causing my cpu usage to spike up to 90% and it was causing the problems. McAfee posted a fix on their site and it eliminated a number of video related problems I was having.