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c100 clips inexplicably interlaced with strange motion

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Erick Stoll
c100 clips inexplicably interlaced with strange motion
on Jan 28, 2015 at 8:14:23 pm

Hey All,

I'm shooting on a C100 in 24p (23.98) 1080p. Several shots I took recently look very strange--weird, 'slow' movement, and seem to be interlaced.

There's no way the camera settings were changed, and the shot immediately before and after this look fine. But it isn't the only shot on the card like this, there are at least 4 or 5 others, maybe more. The card is a 64gb Sandisk extreme pro, and I filled it completely before dropping the footage. The footage looks this way whether opened in Premiere, VLC, or logged and transferred in FCP 7.

I uploaded this clip as an example:





You have to load it in 1080p to see the interlaced problem.

Here's an affected raw MTS file, if you're interested https://www.dropbox.com/s/nlmcxid14z4c1fw/00172.MTS?dl=0

Any thoughts on why this happened, and if these shots can be saved?

Thanks,
Erick


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Todd Terry
Re: c100 clips inexplicably interlaced with strange motion
on Jan 28, 2015 at 9:01:16 pm

Well that is weird weird weird....

I was going to ask you to check the clip properties, but since you provided a source file I was able to check it myself. I downloaded it and threw it on a 1080 24p timeline that I happened to have open...




As you can see, the clip properties show to be 1080, 23.976, and progressive. All should be good.

But it's not... because that is not a progressive clip. Despite what the properties say it is absolutely totally without-a-doubt 100% assuredly an interlaced clip, and most decidedly not progressive.

Looking at it on my broadcast HD monitor (an LCD monitor) when video is parked on a frame with motion I can definitely see the two fields ghosting together. Furthermore, and more proving, when looking at it on the down-converted standard-def stream that comes out of my system on an old-fashioned CRT monitor (yes, we keep those around for monitoring what our projects look like in SD), you can definitely tell it is interlaced, with the still frame vibrating back and forth between the two fields.

SO, it was definitely recorded as interlaced. Now, considering that you did not make any camera changes (and are sure about that?) and considering that the clip properties still show it as progressive, something is obviously amiss.

I'm now going to say words that no one wants to hear, "I think you have a camera problem." Not just a settings issue of operator error of some kind... unfortunately I think you have a repair issue. Most of that is based on the fact that the properties aren't what the clip actually is, there's no way for that to "accidentally" happen by doing something wrong.

Can you salvage the footage? Maybe, to a degree... by merging the fields. In Premiere you would select the clip on the timeline and go to "Field Options" and choose "Flicker Removal"....




...and that will merge the fields into one frame. It still doesn't look great (you can still see the interlacing), but it looks a lot better than it did.

I think there is a way (in After Effects, maybe?) to extract the fields so that each frame is just made up of one field (I'd guess the upper) and the other field is discarded. I'm not sure because I have never needed to do that, but I think it can be done. That would give you true progressive footage. Unfortunately though you'd lose half of your lines of resolution.

As for the camera... sorry but unless there is some very wacky setting that I don't know about, I think it needs professional attention.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Erick Stoll
Re: c100 clips inexplicably interlaced with strange motion
on Jan 29, 2015 at 10:40:35 pm

Thanks Todd. I finally got an answer back from Canon, telling me to send the camera in. There is no way I could have changed settings for these clips!

Thanks for the help with merging frames, I'll see how that looks.

- Erick


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Todd Terry
Re: c100 clips inexplicably interlaced with strange motion
on Jan 29, 2015 at 10:58:33 pm

Sure thing.

I figured the camera needed service.

The extra weird thing is that not only is a file that says it is 24fps very obviously interlaced... but I don't even know how that is possible. In fact it should be impossible... as there is no such thing as a format that is both 24fps (23.976fps) and interlaced... that simply doesn't exist. All 24p clips are by their very definition progressive, there's no such thing as 24i.

Anywho, I hope Canon takes care of it for you.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Craig Alan
Re: c100 clips inexplicably interlaced with strange motion
on Feb 1, 2015 at 3:44:32 pm

What if you played the clip from the camera with interlace settings and recorded it in progressive with a video recorder?

Mac Pro, macbook pro, Imacs (i7); Canon 5D Mark III/70D, Panasonic AG-HPX170/AG-HPX250P, Canon HV40, Sony Z7U/VX2000/PD170; FCP 6 certified; FCP X write professionally for a variety of media; teach video production in L.A.


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Todd Terry
Re: c100 clips inexplicably interlaced with strange motion
on Feb 1, 2015 at 10:31:40 pm

While you can do that, I'm guessing that would yield the same effect as merging the fields that I suggested in a post above. You'd have a progressive file then, but it would still be obvious that it was made from an interlaced file.

BUT... there might be a slight quality improvement in doing it that way, as using the "flicker removal" setting under the "Field Options" in Premiere does seem to slightly slightly soften the image just the tiniest bit. It might be sharper to do the camera playback trick that Craig suggests.

Sadly though it still will not make the footage appear to be natively progressive.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Erick Stoll
Re: c100 clips inexplicably interlaced with strange motion
on Jun 12, 2015 at 9:22:54 pm

An update to this vexing problem:

Canon has had my camera 3 months or so now, trying to diagnose the problem. They sent me a loaner camera meanwhile. But...

The loaner camera produced clips with similar problems!!! Here's the thing--it happened on the same 64 Sandisk extreme SD card that it did on my other camera.

Has anyone heard of an SD card being at fault for a problem like this?

Also, is there anyway to tell from c100 metadata what size sd card the footage originated from? I'm trying to figure out if this has happened accross multiple cards, or just the 64gb card, where I first noticed it.


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Todd Terry
Re: c100 clips inexplicably interlaced with strange motion
on Jun 12, 2015 at 10:03:07 pm

[Erick Stoll] "Has anyone heard of an SD card being at fault for a problem like this?"

Haven't heard of that, but anything is possible (even though I don't see how it could be). I would definitely scrap that card, though. Or at least stop using it until this happens on another different card as well. If it is the card, this might be one of those "I know know idea why this is happening, but I know how to stop it" issues.




[Erick Stoll] "...anyway to tell from c100 metadata what size sd card the footage originated from?"

Nope, the metadata does not include that info, sorry.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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