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Avid 50i project but 25p footage?

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Mark Norgate
Avid 50i project but 25p footage?
on Oct 26, 2012 at 9:32:40 am

Hi,

Sorry to ask a probably obvious question, but my avid project is at 50i, and when I import my XDCAM footage it comes in at 1080p. Is this correct? When I play this footage out will it then be i or p? Slightly confused.

Any help appreciated!

Thanks


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Bouke Vahl
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 11:40:01 am

If the footage is shot 25p, your output will be 25p, even in an I project.
EXCEPT some effects! If an effect has motion (dve, wipe), those parts will be interlaced.

For broadcast, i normally edit P in an I project, as i like my (rolling) titles in i, while the director (never understood why) prefer P to shoot.
If the output is internet / big screen / computer monitor, it's of course wise to stay P all the way, so you don't have to deinterlace the final output.

hth,

Bouke

http://www.videotoolshed.com/
smart tools for video pros


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Mark Norgate
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 2:00:10 pm

It's for broadcast so I guess I'm good as I am? Only problem I've come up against though is that I need to output some uncompressed QTs for other facets of the production but Avid wont let me export 'same as source'. Is this because of editing p in i? Any workarounds? Thanks so much!


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Michael Phillips
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 1:15:24 pm

It's more about the motion in the footage than it is about the footage format itself. Moving objects change position every 1/25th of a second in 1080p/25, and every 1/50th of second in 1080i/50.

25p footage in an interlace project will still have the same frame to frame (and not field to field) movement in it but all effects will be processed as fields - so a horizontal wipe for example would have 50 different positions every second, while the car moving by changes every 25th.

You can create interlace looking footage from your progressive footage by applying the motion effect at 100% with progressive as input and interlace as output.

When outputting as a video signal, it will be 50 fields of interlace material per second. How the motion looks will be based on the above.

It would be great if Avid offered a option when rendering effects while in an interlace project to be frame based or field based. Right now, the project types defines that.


Michael


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Mark Norgate
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 1:28:19 pm

Many thanks, Michael. That's really helpful.


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Bouke Vahl
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 2:11:55 pm

Michael,

[Michael Phillips] "You can create interlace looking footage from your progressive footage by applying the motion effect at 100% with progressive as input and interlace as output."

Eer, what would that do? (My avid is busy at the moment...)
The other way around is a quick and dirty de-interlace trick, but this 'should' do nothing...
Or am i missing something?


[Michael Phillips] "It would be great if Avid offered a option when rendering effects while in an interlace project to be frame based or field based. Right now, the project types defines that."

And what would be the point of that? I can imagine an option where you can set the p or i per render, but overall, for broadcast / dvd / BluRay select I, for other stuff, use P if the footage is P.

For Marc,
If your input is XDcam, it's long GOP MpegII.
Avid cannot export same as source, as that would mean I frames are lost (you did not cut on exact i frames...)
Quickest way is to export to XDcam. You end up with an MXF file that is good enough for rock 'n roll (not uncompressed, but same codec, same as source isn't uncompressed either.)
All half decent systems / software accept these MXF's, and no worries about color space / gamma / levels yadda..

Bouke

http://www.videotoolshed.com/
smart tools for video pros


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Mark Norgate
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 2:28:07 pm

I don't have the choice unfortunately, specifically asked for quicktimes. I think creating QTs using HQ DNxHD should do the trick.


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Bouke Vahl
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 2:41:10 pm

Well, if they ask for "quicktimes", they aren't very descriptive.
So there is no guarantee they have the Avid codecs, and chances are they start bitching about that...

So, get more detailled specs, or use a codec that everyone can read (Animation @ 75% is usally good)

Bouke

http://www.videotoolshed.com/
smart tools for video pros


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Michael Phillips
Re: Avid 50i project but 25p footage?
on Oct 26, 2012 at 2:45:44 pm

[Michael Phillips] "You can create interlace looking footage from your progressive footage by applying the motion effect at 100% with progressive as input and interlace as output."

Eer, what would that do? (My avid is busy at the moment...)
The other way around is a quick and dirty de-interlace trick, but this 'should' do nothing...
Or am i missing something?

[mep] I am going on the premise that he is in a 1080i project because he needs to be for whatever reason. If he wants interlace footage in an interlace project from progressive media, he can use the motion effect to create that. It's just a suggestion.


[Michael Phillips] "It would be great if Avid offered a option when rendering effects while in an interlace project to be frame based or field based. Right now, the project types defines that."

And what would be the point of that? I can imagine an option where you can set the p or i per render, but overall, for broadcast / dvd / BluRay select I, for other stuff, use P if the footage is P.


[mep] The reason is that if I am tracking an effect on frame based media, I want the render to be progressive for that particular shot - same for interlace. It's a matter of choice (as an option on a per shot/effect basis) that the user can choose the behavior and resulting look. The same way it in the NTSC world of past, having a rolling title incorporate a 2:3 cadence for film material that had 23.976 so that the movement would match - MPEG encoders have a hard time with flattened footage that has a mixture of cadences in the same frame. The feature would have eliminated the need to first do a "remove 2>3 cadence, apply effect, render out new 2:3 back to 29.97. It's all about matching VFX to the material and the motion within the frame.

And you cannot choose to render P or i on effects (other than motion effect as an effect) in an interlace project, which is why I brought it up - again, because this project is set to 1080i for whatever reason.

Creating good looking file based exports will depend on where the file is going and what it will be seen on. With more and more screens being progressive, it has always made sense to me to work in progressive, but interlace is still a big part of the acquisition, and libraries, so now it is a matter of dealing with it in post. When I have had interlace footage in a progressive project, I have used the motion effect (fluid) to make progressive from interlace as most time is created the progressive look to match the other material, rather than just basic field blending.


Michael


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Chris Harlan
Re: Avid 50i project but 25p footage?
on Nov 3, 2012 at 9:10:43 pm

[Michael Phillips] "When I have had interlace footage in a progressive project, I have used the motion effect (fluid) to make progressive from interlace as most time is created the progressive look to match the other material, rather than just basic field blending. "

That's quite a bit of clever. I'll remember that. Thanks!


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