Emergency with an HVX200. Need help immediately!

March 13, 2008 10:52 AM

Anyone here work on the Panasonic HVX200 camera? We're having a footage emergency and need advice immediately -- seriously, epic karma points to the piler who can help us out. Details inside.

Last night we did a music video shoot on a friend's HVX. We shot on P2 cards, at 720p, and shot at two different variable frame rates -- 30p and 60p, so that we could get two different levels of slo-mo. When we imported the footage into Final Cut, though, the 30p footage (and only the 30p footage) won't play back properly -- it stutters, loses audio sync (in that the audio finished halfway before the video does), and seems to be missing large chunks of the clip. However, the footage in question play back fine in-camera. We have another shoot today, and need to figure out what's going on ASAP so we can safely wipe the footage off the card. Any thoughts?

posted by tweebiscuit to computers & internet (11 comments total)

Oh, I should have specified -- the final video is going to be at 24fps -- we shot at 30fps in order to get a subtle slo-mo effect. I believe we used the HVX's "Variable Frame-rate" feature to do this.
posted by tweebiscuit at 10:58 AM on March 13, 2008

Could be a problem with Final Cut Pro. Which version are you using? Are you watching the clips from the bin or in the sequence?
posted by infinitewindow at 11:09 AM on March 13, 2008

I'm using 6.0.2, which is the newest. This is watching them from the bin -- there's been no reason to put them into a sequence, yet, as they're obviously messed up as soon as you watch them. I checked out their framerate in Cinema Tools, and it seems to check out -- I also experimentally tried conforming the clip, but that didn't help.
posted by tweebiscuit at 11:15 AM on March 13, 2008

Oh, the same is true when we play them in Quicktime Player or another app.
posted by tweebiscuit at 11:16 AM on March 13, 2008

There's a difference between the camera's time base and the frame rate. In general, the DVCProHD format will record at a 59.94 timebase (the exception being when recording to P2 formats, where 24n becomes an option), even if you've set a different frame-rate to record at. What this means is that if you shoot at 30fps, the recorded video stream actually contains duplicate frames in order to fit the 30fps video into a 59.94 timebase. So when you capture at 59.94 in Final Cut, you're seeing every single frame of the raw capture, duplicate frame included.

The key to getting this to work right is to remove the duplicate frames, and conform your footage to the same timebase that your FCP timeline will be at. You do this using the DVCProHD Frame Rate Converter (FRC) in the FCP "Tools" menu.

You should really peruse the "HD and Broadcast Formats" PDF manual which iks available in your FCP Help menu, because it explains all of this (admittedly confusing) information in depth.
posted by melorama at 11:53 AM on March 13, 2008

Hey melorama -- I tried that out, but it doesn't work -- the clips themselves are reported by FCP as being 29.97fps, and the HD Frame Rate Converter tool claims that it can only operate on 59.94 or 50 fps files. So it looks like the footage was actually imported at 30fps. And we did record at a 24n timebase, I believe.
posted by tweebiscuit at 1:34 PM on March 13, 2008

So it looks like the footage was actually imported at 30fps. And we did record at a 24n timebase, I believe.

Yikes. That would be bad.

If you intend to edit at a 24/23.98 timebase, there's no reason to transfer the 24n P2 footage at 30, and *especially* not at 30p.

I'd strongly recommend that you just dump the raw contents of your P2 cards to a harddrive for now (carefully following the directions on page 79 and 101 of the aforementioned PDF guide), and worry about doing a proper Log and Transfer later, when you're ready to edit.
posted by melorama at 2:00 PM on March 13, 2008

Hold on -- you're right in a sense. The frames are indeed duplicated, but it looks like the playback rate is still 30fps, so everything is playing slower, and the clips seem to end half as soon as they should. Looks like Final Cut is getting confused about the frame rate. Any clues for correcting this?
posted by tweebiscuit at 2:13 PM on March 13, 2008

melorama -- in terms of dumping the raw contents to a harddrive, do you mean the instructions under "Capturing over Firewire as if a P2 card Were a Tape in a VTR"?
posted by tweebiscuit at 2:22 PM on March 13, 2008

Whoops, turns out I was wrong! We actually recorded at 720/24P, not 24PN, with the frame rate set to 30 for a mild overcrank effect.
posted by tweebiscuit at 2:30 PM on March 13, 2008

Ahah! I tried recapturing one of the 30fps clips with "Remove advanced pulldown" unchecked in Log and Transfer preferences, and it worked! However, while on the shoot we captured a batch of cards with "Remove advanced pulldown" checked, and then wiped the cards -- is there any way to reverse that operation, or do we have to resign ourselves to having lost that chunk of footage?
posted by tweebiscuit at 3:00 PM on March 13, 2008