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Exporting HD project w/o line factoring

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David Lewis
Exporting HD project w/o line factoring
on May 7, 2013 at 11:31:12 am

I've just finished a "personal" video project shot on my home HD (AVCHD codec) camera and imported AMA and transcoded to DNxHD 185.

Very simple edit, but when I exported it as an H264 MOV I get all these line factoring. It was shot at 1080i/50fps(PAL system), though the fps on the MC 6 project shows it as 25 fps.

I've seen these lines before when working with DV, but not with HD files. I'm no doubt missing something somewhere in the "chain" of exporting. Any suggestions how I can get rid of these lines?

BTW, I exported the sequence as H264; Data rate limit to 5000, native dimensions.

Thank you in advance for you help/advice.

David C. Lewis
Editor- Director
DCL Video Productions


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James Beattie
Re: Exporting HD project w/o line factoring
on May 7, 2013 at 11:46:45 am

Can you try a QT refernce to the desktop and see if you get this factoring?

Is it a tearing?

James Beattie
ACSR Elite/Avid ACI, Apple Certified Technician

Consulting for Workflow and Digital Technologies at Comprehensive Technical Group


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David Lewis
Re: Exporting HD project w/o line factoring
on May 7, 2013 at 12:40:21 pm

James, Thank you for your quick response.

I tried a QT Ref. file. It seems not to have those line factoring... like seeing the "lines" of the frames horizontally across the screen. But, it did not play smoothly, a very heavy file so it seems.

David C. Lewis
Editor- Director
DCL Video Productions


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Shane Ross
Re: Exporting HD project w/o line factoring
on May 7, 2013 at 5:43:13 pm

[David Lewis] " It was shot at 1080i/50fps(PAL system), though the fps on the MC 6 project shows it as 25 fps."

Just so you know, 1080i50 runs at 25fps. The "i" indicates INTERLACED, which is two fields per second. So the number that follows indicates how many fields per second. 50 fields per second is 25fps. So you are shooting an interlaced, 25fps format.

That also is what you are seeing...interlacing. This works fine for TV, but is bad bad bad for the web and computer only viewing. You need to shoot Progressive for that. 1080p25...the "p" means progressive, full frames. So 25p is 25fps, no interlacing.

DV, SD and HD can be interlaced. If you don't want interlaced...you can de-interlace when you export...and just shoot PROGRESSIVE from now on.

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


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Pat Horridge
Re: Exporting HD project w/o line factoring
on May 8, 2013 at 10:08:09 am

Yes sounds like 50i source material with interlaced content.
If you work with a 25P project format and the media is correctly flagged as interlaced MC will drop a motion adapter to de-interlace the content.
Or work interlaced and then choose to de-interlace when you encode.

Lots of choices on how to de-interlace and getting it right is important to retain quality.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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David Lewis
Re: Exporting HD project w/o line factoring
on May 8, 2013 at 10:27:15 am

Hi Shane and Pat:

Yup... it was shot as "i" and thus this problem exists.

I'll assume that if I export and choose "deinterlace" that should solve/help the line/field problem be resolved.

Would it be better to export in it's native codec and not deinterlace and then take it to Sorensen Squeeze to make it a deinterlaced H264 for a disk or Interent viewing?

And advice well placed... I do try and shoot "p" on professional work, but this was shot on my consumer camera and I didn't think to even look for "p" (found out it DOES have a 50p option... too late) option.

Thanks for your input.

David C. Lewis
Editor- Director
DCL Video Productions


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Pat Horridge
Re: Exporting HD project w/o line factoring
on May 8, 2013 at 10:33:07 am

I don't use the export option in MC for anything other than same as source exports as it's slow and not great.
O I'd either de-interlace in MC using motion adapters and then export as a Progressive file or export interlaced and de-interlace in Squeeze.
Squeeze as some nice controls over the de-interlacing and you can preview the result to get it right. Also Squeeze gives you more control over the encode parameters and is often quicker.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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David Lewis
Re: Exporting HD project w/o line factoring
on May 8, 2013 at 12:19:12 pm

Thank you Pat.

Your advice sounds good. I now recall someone else once told me best to always export "as is" from the edit system (AVID and FCP, I believe). Then, as you noted, work with the media file in a tool such as Squeeze.

I'll try that and I hope it does the trick. This will be a good trial/error preparing for jobs that aren't a personal home video project!

All the best,

David C. Lewis
Editor- Director
DCL Video Productions


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