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Budrick21
720p24 conversion headaches
on May 19, 2007 at 1:10:24 am

I'm on a project that's mastering in 720p, but we're bringing in a bunch of 525i material (beta sp and DVD rips). Some of the converted material displays some stuttering or strobing, but only on some cuts and not on others. I could understand if all of it were stuttering, or not, but why some cuts and not others? I understand that there are frame rate conversions going on, but if some of the material plays smoothly why shouldn't all of it?

Is there a resource that someone could point me to that would help me understand what's going on when footage is converted from 525i to 23.98p?




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JeremyG
Re: 720p24 conversion headaches
on May 19, 2007 at 2:26:42 am

Sup Budrick?


how did you decide to convert? Is all the 525i footage recorded in 60i or was some of it recorded 24p over 60i?

Jeremy


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gary adcock
Re: 720p24 conversion headaches
on May 19, 2007 at 12:49:37 pm

[JeremyG] "Is all the 525i footage recorded in 60i or was some of it recorded 24p over 60i?"

I am going to guess it is the DVD material, I have never been able to get that stuff to look correct in a timeline.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Oliver Peters
Re: 720p24 conversion headaches
on May 19, 2007 at 7:12:24 pm

If you can afford the speed change, then one option is to deinterlace and render new media. Then open that in Cinema Tools and change (conform) the media clip to the desired timebase. Bring into the 720p/24 timeline and scale. This should result in a slower clip without dropped frames or interlace artifacts.

Deinterlace in Shake or one of the Nattress plugs for best results in software. Otherwise convert externally using a Teranex unit.

Sincerely,
Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com


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Budrick21
Re: 720p24 conversion headaches
on May 19, 2007 at 7:26:36 pm

Thanks, Oliver.

I like you suggestion because I think it makes the current situation look more viable (I don't think the team will put up with the effort of option 1 or the expense of option 2)


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Budrick21
Re: 720p24 conversion headaches
on May 19, 2007 at 7:20:02 pm

Hi Jeremy and Gary


The Beta SP material is fine for the most part, and working as expected. I brought it in as 60p, and it plays on the 24p timeline when we enable Unlimited RT, and of course if we render it plays in Safe RT. The DVD-ripped stuff is a little more trouble.

I'm thinking that a film (true 24p) converted to an NTSC DVD, and then ripped to DV, and then laid onto a 720p23.98 timeline is bound to show some artifacts. I'm amazed it looks as good as it does. I want to suggest that they play the DVD into a varicam deck and ingest from that.

The bonus question is how come we can't pull match frames from the DVD material. Maybe because it never had timecode to begin with, then it goes through a black box (DVDxDV) and then it's just dropped into the 720p timeline.

I may ask them to rethink their workflow...

Gary -

Thanks for your perspective on this. I can't believe anyone expects this to work as if all the material were 24p origination.


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Oliver Peters
Re: 720p24 conversion headaches
on May 19, 2007 at 7:58:07 pm

[Budrick21] "I don't think the team will put up with the effort of option 1 or the expense of option 2

Just so you understand, though, you MUST deinterlace the content in some way while it is still interlaced before you do anything else to it. It basically has to be turned into 30p before changing the timebase or scaling. Nattress is the best, low cost way to deinterlace with some control. All internal FCP deinterlacing will greatly soften the image.

Sincerely,
Oliver



Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com


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Budrick21
Re: 720p24 conversion headaches
on May 19, 2007 at 10:18:50 pm

Thanks for the warning. This is just for the offline, I think. But if it's also the final, I'll be back with more questions....


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infohou
Re: 720p24 conversion headaches
on May 23, 2007 at 7:39:26 pm

[Oliver Peters] "All internal FCP deinterlacing will greatly soften the image."

Anybody know if this is improved in FCPS2?

Robert


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JeremyG
Re: 720p24 conversion headaches
on May 20, 2007 at 10:24:49 pm

[Budrick21] " I want to suggest that they play the DVD into a varicam deck and ingest from that."

If the DVD is 23.98 already, then there's no reason to change frame rates. Use MPEG Streamclip (it's free) to convert VOBs to whatever SD codec you want @ 23.98, then use an app such as compressor to render a 720p24 DVCPRo HD movie.

Jeremy



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