Serious problem in playback
 

I've got some footage shot in 720p25 and during the playback/capture (eihter though firewire or component), just about every minute, i get some glitches, like a drop frame.. the strange thing is that if I stop, rewind a few seconds, and play that piece again, it's ok.
It's happening with my most recent job, and I just checked on some older tapes, the problem is occurring in places where it didn't show before.

The only thing I did before I started to notice this so frequently ('cause it 's been happening, just no to often) was to play a head cleaning tape - Sony DVM-4CLD. It can't be it, can it?!

What could be causing this?

Thanks.

It could likely have been the cleaning tape...

Ther are slightly different types of lubrication on different manufacturers tapes. Most notably Sony uses a wet system for it's tapes and most other manufacturers use a dry system.

I asked a supposedly knowlegable person about this and he said it didn't matter what brand of cleaner I use. I think he also said they are all dry now.

Do I need the same brand Tape Cleaner and the brand of tape I use?

I highly recommend getting the tape drive professionally cleaned before you run any more tape through it.

I had the exact same problem for a couple of tapes. I tried using a head cleaner but it didn't fix the issue.

So, I checked the tapes themselves by carefully opening the dust cover. I noticed a trail of small dimples punched along the tape at regular intervals. (The spacing of which coincided with the timing of the drop-outs.)

Then I did my own careful investigation of the tape drive and noticed a small metal shard stuck onto one of the white rollers. This shard was punching the dimples as the tape rolled over it, and it was something too big for the head cleaner to get off. (In fact, the action of the tapes winding around this roller likely embedded it further.)

You might be suffering from a similar foreign object, so be sure to get this looked at to make sure you aren't permanently damaging your tapes.

(Having the tape play properly after rewinding happened to me as well, so it's likely just that the drive added more tension to the tape at that section, perhaps flattening out the dimples. But regardless, those tapes are now permanently damaged.)

Sergio -

When you say "stop, rewind a few seconds, and play" do you mean rewind and check the tape or rewind and play on NLE timeline?

When you say "older tapes", did you recapture from the tapes or just check the computer clips that were captured earlier?

I'm having similar problems, I'd like to know how similar.

Tape is fragile, since the HDD recording system is bulky, needs another power source, adds an extra cable and is only 40 or 60 Gb, tape is still in my cam. To minimize a potential problem I never re-use tapes. It might seem over precautious, but I must say the cassette mechanism of the JVC is probably the thing I like least about this lovely camera: it isn't sturdy at all, you need to press in exactly the right spot to close it if you want it to open afterwards, it isn't particularly dust-proof - it just overall seems to have the lowest build-quality and ruggedness of the camcorder (together with the VF arguably).

So, the precautions I take:
- never re-use tapes
- always use the same brand of tapes (for the same lubricant)
- use tapes that are in a dustproof box (like the DVCAM tapes)
- be carefull to store the tapes and the camera away from dirt and dust (that means, tapes are on my desk all the time, but always in their box, never completely uncovered)...
- I NEVER use tapes that someone gives me...

I just sent my camera for repair, hoping they'll see the problem and fix it.

I don't know if it was the head cleaner, but if it was, there SHOULD be a list of the tape head cleaners that we can and can't use in this camera, for as strange as such might seem...

Earl, I really don't want to go through the camera's tape drive or anything... I'll leave it all to the specialists... About the tapes themselves, I surely hope that they're not damaged. Anyway, what else could I have done to prevent it? Clean the heads before the shoot, and take the chance that it might have been even worse!?

George, this situation happens when playing back from the camera.
In order to check if that problem came when shooting with these tapes, I picked up some tapes from previous jobs (older tapes) that played well when I first worked with them, and now they have the same problem.

These were all brand new Fuji tapes, which are the ones I have always used since I got the camera.

Another *interesting* thing is that I'm just editing another job shot in DV50i (3 tapes), captured from a Sony VCR, and there's not a trace of those dropouts...hmmm...

Sergio

It sounds like your problem is the reverse of mine. I get clean playback on component out to hd monitor, jumpy playback in FCP or QT after firewire capture. Comparing notes won't be much help.