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Strange corruption on EX3 footage in FCP - what is this?!

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Jamie Kennerley
Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 9:51:51 am

I'm having some strange problems with my EX3 footage in FCP (6.0.5).

I download with Sony XDCAM transfer software (via cable), and the clips look fine when I'm previewing them in there. I then open my FCP project and import the clips, and often there's a fine line-based corruption on the image.

It seems to be when there's more movement in the image, or around big differences of colour/contrast, which suggests that it could be a compression issue, no?

I've exported a quicktime, so you can see what I'm talking about.
The strange thing is however, that when I watch the clip in Quicktime I don't see the corruption (or don't think I see the corruption). When I import the clip back into FCP I then see it again.

You can download the clip here (95mb): https://rcpt.yousendit.com/647489268/c59e8ef4f0544af528315c3584a460f9

You can see it around the lamppost in the first part of the clip, then around the edge of the guy's black jacket - in fact a little bit all over) in the second part of the clip. (It's supposed to be a crappy video.) As I've said, you may need to drag it into FCP to see it.

I get it on clips from both my SxS 8gb cards. One card I've tried in an EX1 user's Macbook Pro (straight in the side slot) and he has seen the same thing when he's viewed one of my clips in his FCP. He said that he thought it was down to the mp4 compression and the occasional problems the camera has with creating an image this way, compounded by the strange way FCP tries interprets that, or tries to play it, and doesn't always succeed. Does this have any truth to it?

Here I'm shooting at HQ 720/25p, but I've seen it at HQ 1080 too. I've tried downloading the same clips with Log and Transfer within FCP, and I get the same issue.

Although this doesn't seem to be visible outside of FCP, I'm now very wary of using my camera for pro work until I know what this is, which makes things a bit difficult for me.

Can anyone advise at all? I'd be happy to post any further information you may need.

Much appreciated in advance.

Jamie Kennerley



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Craig Seeman
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 2:07:58 pm

Maybe I don't understand the problem but that clip looks OK in both Quicktime 7.6 and FCP 6.0.5 on my system. You really can't judge things in FCP because it's doing all sorts of things like scaling to play in Viewer and Canvas real time. Play it out to an HDTV or Quicktime at full size to judge. Maybe you need to provide a screenshot of exactly what you're seeing but the video looks fine to me.



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Jamie Kennerley
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 2:46:29 pm

Okay, that's interesting. I'm starting to think that it's a playback problem, specific to my system (and, by coincidence, maybe to the other user's system that I previously tested on).

When I scrub frame to frame on my footage, I do get the funny lines appearing sometimes as the frames are resolving, but it isn't on the still frames.

I'm on a Macbook Pro, 2.4GHz Core 2 Duo/2GB/ 256mb VRAM. Could it be that I need a stronger video card to playback footage of this size?





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Craig Seeman
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 3:06:46 pm

[Jamie Kennerley] "When I scrub frame to frame on my footage, I do get the funny lines appearing sometimes as the frames are resolving, but it isn't on the still frames. "


That's the giveaway for me. That's usually how FCP behaves when it has to process the image to show real time. When it's still you'd get full resolution. In fact if you set Canvas or Viewer to 100% and park on still you can full resolution with FCP scaling. The only safe way to judge quality of source issues is to set to 100% and park on a still. Even then it's always better to use broadcast QC monitor.




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Jamie Kennerley
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 3:14:31 pm

Yes, there's nothing as untoward on the still image, event at 100%.

Do you think I'm pushing the video card with the EX3 footage?



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Jamie Kennerley
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 3:15:56 pm

PS. This shouldn't ever really be a problem when it's exporting should it? Or could it still have problems building a movie?



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Don Greening
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 4:04:40 pm

[Jamie Kennerley] "PS. This shouldn't ever really be a problem when it's exporting should it? Or could it still have problems building a movie?"

If you're not seeing a picture problem when the playhead is parked on a frame then there's nothing wrong with the actual footage. It's just a playback thing. You shouldn't see any glitches in anything you export from the timeline, either. Remember, if you've set FCP to play back using "unlimited plus dynamic RT" Final Cut Pro will lower the playback resolution (sometimes severely) to avoid dropping frames so you can have smooth playback.

As my esteemed peers have mentioned, your best indicator of the actual picture quality should be judged using a broadcast monitor. Failing that, open an EX clip in QT Player set to full res. and have a look that way OR use the "Digital Cinema Desktop Preview" view option within FCP. This is where it's nice to have 2 monitors for editing where your 2nd one is a 23" display so you can see the full raster 1920x1080 EX image in all its "native" glory.

- Don



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Clint Fleckenstein
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 4:07:44 pm

Do you by chance have your playback quality set to Dynamic? Just a shot in the dark here.

Cf


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Jamie Kennerley
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Jan 30, 2009 at 6:22:05 pm

I've literally just had to surrender my laptop to the Apple shop whilst they replace the top layer (trackpad and mouse weren't working)! So, I'll check those settings in a few days when I get it back. This is all very helpful though, thanks, and quite reassuring that the footage should be fine.

Certainly worth looking to invest in a second monitor though it would seem, especially since it's a quite a step up now from HDV.

Many thanks for your thoughts. I'll report back once I have checked things on the machine.




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Jamie Kennerley
Re: Strange corruption on EX3 footage in FCP - what is this?!
on Feb 2, 2009 at 4:46:50 pm

Got my computer back now.

I get exactly the same 'problem' when I play full screen desktop. I've also toggled between the various playback settings - dynamic (which it was on), high, medium, low, and see the same thing happening on each setting.

Kind of suggests it's not a playback issue then, or at least not of the kind we thought.




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