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Is this an interlace issue?

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Enrico Lappano
Is this an interlace issue?
on Apr 3, 2012 at 4:19:48 am

I'm getting horizontal lines on 7D with my 29.97 fps footage. I'm guessing it's an interlace issue. Editing in FCP with sequence preset at ProRes 422 30p and Video Playback is Blackmagic HD 1080i 59.94. I converted footage to ProRes 422 in Mpeg Streamclip, and unchecked Interlaced Scaling. The FCP Field Dominance setting is None. it. The monitor I'm using is just a Sony Bravia (HDMI), so I'm wondering if that could be an issue, bit don't know why I'm getting these lines, particularly on tree branches in forest scenes. After trying to research this a while, and trying a number of things, I'd really appreciate your help on this to diagnose what it could be and find some clarity!

Thanks


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Shane Ross
Re: Is this an interlace issue?
on Apr 3, 2012 at 4:24:32 am

That camera doesn't shoot interlaced. It must be something else. Might be in how you converted it.

Download the Canon EOS log and transfer plugin, and use Log and Transfer. I have a link to it here:

Tapeless Workflow for FCP 7 Tutorial

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Enrico Lappano
Re: Is this an interlace issue?
on Apr 3, 2012 at 2:28:09 pm

Thanks for the tutorial Shane.

When I go to Log & Transfer and try to import the H264 files from the folder of that shoot, a warning window appears saying, "contains unsupported media or has an invalid directory structure. Please choose a folder whose directory structure matches supported media."
In your tutorial you mention that when downloading the original SD card, everything on the card must be included. But because it was a while ago, I may have only downloaded selected files from only that shoot and not stuff that was not erased and recorded before.

You mention copying the folder. Would that still work?


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Enrico Lappano
Re: Is this an interlace issue?
on Apr 3, 2012 at 3:18:10 pm

I should add re "copying the folder" that the folder I'm transferring from is not on an extended HD, but already on my Mac Pro. So I'm not sure of the difference?

Can I fix the directory structure so it supports the media. The names of the files are the original H264 that were downloaded to the Canon Image Browser and they are in correct sequential order without any files missing from that day's shoot.

I appreciate your feedback on this issue.


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Shane Ross
Re: Is this an interlace issue?
on Apr 3, 2012 at 4:43:06 pm

OK then, Log and Transfer won't work. Try 5DtoRGB. This will be slower, but a better conversion.

http://rarevision.com/5dtorgb/

Can you post a pic of this footage? I'd like to see if it is indeed interlaced. MPEG STREAMCLIP normally works fine...I think you didn't get the settings right. And no, I don't know what the settings are, as I use Magic Bullet Grinder or Log and Transfer to bring in my DsLR footage

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Alex Elkins
Re: Is this an interlace issue?
on Apr 3, 2012 at 3:09:17 pm

[Enrico Lappano] "don't know why I'm getting these lines, particularly on tree branches in forest scenes."


Could you post a screenshot?


Are you able to set the Blackmagic card to monitor 29.97p rather than 59.94i?

Alex Elkins
Twitter: @postbluetv
http://www.postblue.tv
Post Blue showreel
Latest work: Greyhounds in Motion at 500fps
My Vimeo Pro page


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Enrico Lappano
Re: Is this an interlace issue?
on Apr 3, 2012 at 3:46:59 pm

Hi Alex,

Here's a screenshot example from my computer monitor. On the Sony Bravia the small branch horizontal lines are more distinct.

http://i1.creativecow.net/u-upload.php#

I'm using the Blackmagic Decklink HD Extreme card via HDMI. The video Playback setting is Blackmagic HD 1080i 59.94 - 8 Bit (1920x1080). There doesn't seem to be a 29.97 1080p option.


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Enrico Lappano
Re: Is this an interlace issue?
on Apr 3, 2012 at 3:50:56 pm

Sorry, here's a correct screenshot post (I hope).



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Alex Elkins
Re: Is this an interlace issue?
on Apr 3, 2012 at 4:22:45 pm

To me that looks exactly how I'd expect a DSLR shot of a load of branches to look.

It's not unusual that DSLR material would have aliasing like this, plus foliage (and brickwork) are notoriously bad for it - certainly doesn't look like an interlacing issue to me and my guess is that the larger Sony monitor is just accentuating the aliasing.

Try turning the sharpness down on the Sony Bravia. This obviously doesn't change the fact that the actual material has aliasing problems, but consumer monitors like that do tend to have the sharpening up fairly high by default, which could be skewing your judgement of it.


OR...
I could have it completely wrong, and the image you've posted isn't telling the whole story. Are you seeing similar issues on other shots? (ie shots other than branches).

Alex Elkins
Twitter: @postbluetv
http://www.postblue.tv
Post Blue showreel
Latest work: Greyhounds in Motion at 500fps
My Vimeo Pro page


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Enrico Lappano
Re: Is this an interlace issue?
on Apr 3, 2012 at 5:17:29 pm

The sharpness on the Sony is at minimum. But yes, it also shows up on some foliage, which sometimes comes out a little clumpy.

Is this something that a frame rate like 29.97 rather than 23.98 will accentuate on the DSLR? I agree that there's no use changing the monitor settings.

Shane, I just downloaded 5DtoRGB and I'll try that as well.


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Alex Elkins
Re: Is this an interlace issue?
on Apr 3, 2012 at 5:23:52 pm

[Enrico Lappano] "Is this something that a frame rate like 29.97 rather than 23.98 will accentuate on the DSLR?"

No - this is an inherent problem with the way the DSLR cameras work when recording video. Some are better than others. The Canon 1D MarkIV is one of the better ones for instance.


I agree with Shane that 5DtoRGB is worth a try, but I'd be very surprised if it made much difference with this sort of problem.

Alex Elkins
Twitter: @postbluetv
http://www.postblue.tv
Post Blue showreel
Latest work: Greyhounds in Motion at 500fps
My Vimeo Pro page


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Neil Sadwelkar
Re: Is this an interlace issue?
on Apr 3, 2012 at 6:16:50 pm

No there's no interlacing in the still you've provided. What you're probably seeing is the effect of 'binning'. Which is, the use of alternate or 'one out of so-many lines' to create an HD image out of a sensor that has a higher resolution. In any case, you've provided a still of the canvas. The image on your Bravia out the Blackmagic may show some other artifacts that resemble interlacing if the BM card is converting progressive 29.97 to interlaced 59.94, sort of like psf.

And, shooting 23.98 wont make a difference to the binning, but may permit true 29.97 monitoring which might minimize the 'faux interlacing' that your BM card-Bravia TV seem to be doing.

-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India


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Enrico Lappano
Re: Is this an interlace issue?
on Apr 3, 2012 at 10:35:41 pm

I just tried the 5DtoRGB and the same issue is there. Since this is not an interlace issue and it doesn't always happen but I often film nature sequences, are there things to keep in mind that will minimize possibilities of artifacting on DSLR forest filming?

And would it have made any difference if I were somehow able to monitor the video playback in 1080p
at 29.97 instead of 1080i 59.94?

I appreciate your responses very much.


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Michael Gissing
Re: Is this an interlace issue?
on Apr 3, 2012 at 11:42:03 pm

Artifacting from line skipping (or binning as Neil refers to it), plus H264 blocking on shots with complexity is a fact of life for DSLRs. Call it a cost compromise.

So clever inventors have made devides that go behind the lens and diffuse the image slightly to reduce the aliasing & moire . The new 5Dmk3 also has a diffusion built in as a fix, but already I see posts from people who are removing the diffuser.

YOu certainly don't have an interlace issue and changing the Decklink setting won't matter. Make sure your sequence is set to none and the files are tagged as none.


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