seems like interlacing

[david walsh]

I'm not sure if this problem is fixable.

I have some footage that was shot on a JVC gr d230, it was then captured with Stoik converter using a dv codec, saved as data to multiple cd's and uploaded to my computer for editing in Premiere.

On the camcorder screen everything looks fine on playback.

When played from the disks some of the footage looks heavily deinterlaced.

When I play back the footage in Premiere at full quality it looks the same, at draft quality it plays smooth and looks as though there is no problem.

I saved a short sample of the footage, with deinterlace ticked, and the problem stays. I tried deinterlacing with the Boris continuum deinterlacer and the problem stays.

I tried putting the footage into Vdub and separated the fields. With the fields separated it still looks like it's an interlacing problem, but can't be. This was the same when removing either the upper or lower field

I was hoping someone could help and let me know if this is fixable or if it's just a problem with a cheap camera?

David.

[david walsh]

I forgot to add, This occured on two of four cameras. It only happens when there is fast motion. On one camera it's when a drummer gets fast, on the other it isn't as bad and is when a guitarist gets a bit over animated.

The other two were on a pretty still keyboard player and some reasonably still singers. They were ok.

This is what's making me think it's a cheap camera thing.

Hopefully some confirmation or advice will help.

David.

[Crusty]

I'm going to guess the camera shutter 'speed' is at fault. With the cameras set to automatic exposure, the shutter speed may be set by available light and you can get this sort of problem. Other cameras will be 'aperture prefered'', causing depth of focus shifts with changing light. If so the only way to control this is use total manual control of aperture and speed in your shoots. .

[Mark W]

Maybe the fields got swapped on those jerky captures? This gives a similar effect, but the camera prob crusty suggests sounds like the likely prob to me.

Does it still happen if you upload the data of the cd to h drive and play off there? I have got jerky playback when trying to play a dv stream off a cd.

[david walsh]

Thanks for the idea's.

It does still get the same result when played from hard drive. I don't think it can be the fields having been swapped, it seems that if that was the case, when separating the fields it would be left looking clean. Perhaps I'm wrong in that though.

The shutter speed thought seems to make sense. But it still leaves the fact that it looks clean when viewed on the camera's display.

I'm going to try and sort it out to test capture a bit on a computer with a matrox card and see how that goes. If it's the same, then it's a reshoot with some shutter speed expermentation by the looks of things.

Thanks again,

David.

[Mark W]

Camera displays are very crude, have you tried playing the tapes into a tv?

[david walsh]

I made a rough edit with the footage to see how it would go together. This I've played on a TV and the problem is there.

I never tried playing the tapes directly to a tv, and they aren't in my possession at the moment. I'll sort it out to get to see them played back on a tv screen and see what is there.

David.

[LukeD]

I have the same problem. It does show fine on my refrance monitor but as soon as I export I get the same problem.

[irishmark]

I've found this to be down to bitrates both on captuer ing and exporting - try playing round with higher itrates and it should sort you out.

[david walsh]

That would also seem to make sense due to the draft quality playback not having the problem Mark, that would be the lower bitrate that never showed it up though.

Doesn't mini dv have a set bitrate of 25 mbps? Lower bitrates on different codecs isn't an option of course, but how can I raise the bitrate without stepping up equipment to dv50/100 or hd?

David.