How to convert HD 1080 to SD 486 pixel aspect ratio "IN" Shake ?

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Level 2

265 points

How to convert HD 1080 to SD 486 pixel aspect ratio "IN" Shake ?

Hi,

I convert 1920X1080p master to 720X486P in Shake because i like the downscaling algorythm.
But when i put the exported file in Final Cut, it distorts the image to show correct aspect ratio, meaning Shake exported square pixels.

How can i convert 1920X1080p (square pixels) to 720X486p (CCIR601) DV pixel ratio directly IN Shake rather than allowing FCP to "distort" it to show correct image aspect ratio ?

Thanks

Antoine

Message was edited by: Antoine Fabi2

Posted on Mar 27, 2009 8:52 AM

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Answer 1

Mar 27, 2009 11:27 AM in response to Antoine Fabi2

Shake is Pixel Aspect Ration Agnostic. if it's 720x486, that's only because FCP is confused. Is this a "round trip" to shake and back, that might do it...

In any case, simply click on your clip in FCP's browser, type ⌘9, ctrl/right-click on Pixel Aspect, and choose NTSC...

Patrick

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Answer 2

Mar 27, 2009 12:03 PM in response to Patrick Sheffield

Patrick, I'm a bit confused by your answer.

In Shake, I scaled down a 1920x1080 Checker node to 720x486 and FiledOut a Quicktime movie
using the standard DV/DVCPRO - NTSC setting. I then imported it to FCP, and placed it in a timeline
that was set to 720x486 NTSC - CCIR 601, with an NTSC - CCIR 601 pixel aspect ratio.

In order to get the clip to look right in FCP, I followed your steps but set the clip's PAR
to square.

Then the image looked correct.

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Answer 3

Mar 27, 2009 12:39 PM in response to stuckfootage

That's weird... I would think if you had square pixels, it would HAVE to be 720x540...

BTW, I meant to say above:

if it's 720x486 and it's not displaying correctly, that's only because FCP is confused

Patrick

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Answer 4

Antoine Fabi2 Author

Level 2

265 points

Mar 27, 2009 5:16 PM in response to Patrick Sheffield

Nope!!!!

If FCP was confused, then it would display with the incorrect "visual" aspect ratio.
Since FCP apply a -12.5% distort AND it looks correct, i suppose Shake do not convert 1920X1080 square pixels to 720X486 DV (CCIR601) pixel ratio.

I mean, if Shake did its job correctly, FCP wouldn't have to distort the clip to show it correctly... 🙂

I'm still trying to figure how to convert pixels aspect ratio corrctly "IN" Shake. 🙂

Antoine

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Answer 5

Antoine Fabi2 Author

Level 2

265 points

Mar 27, 2009 5:56 PM in response to Antoine Fabi2

Proof...

When i ask for item property in FCP, it confirms it is square pixel ratio out of Shake, that's why it distort the clip to display correct asperct ratio.

That's a Shake problem...
Shake tells you it exports in DV pixel aspect ratio, but it doesn't...

Antoine

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Answer 6

Mar 27, 2009 10:01 PM in response to Antoine Fabi2

In order for 720x486 to be 4:3, it HAS to have a non square (.9) aspect ratio. If it were square, it would be 720x540 (do the math). Shake doesn't care about aspect ratios, that's a display issue. If the image looks distorted, likely thats a result of how you're doing your sizing in Shake...

Wanna post a script?

Patrick

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Answer 7

Antoine Fabi2 Author

Level 2

265 points

Mar 28, 2009 7:42 AM in response to Patrick Sheffield

Hi Patrick,

I have found a simple workaround 🙂

Here's what i did in Shake:
I import the HD 1920X1080 square pixels clip.
I select HDTV1080 as exporting format in the "Global" tab.
I type 720X360 as export size in the Parameters 1 tab.
Render out...

In FCP, i import and reset the distort control to 0 in the clips motion tab.

ET VOILÀ. Everything has the correct aspect ratio without compensation distortion in FCP 🙂

Antoine

Message was edited by: Antoine Fabi2

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Answer 8

Mar 28, 2009 10:41 AM in response to Antoine Fabi2

Wait - you were NOT doing centercut? You were doing anamorphic? And now you're letterboxing?

Patrick

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Answer 9

Antoine Fabi2 Author

Level 2

265 points

Mar 28, 2009 11:18 AM in response to Patrick Sheffield

Exactly Patrick,

I had to letterbox.
I was converting a 1080 master to SD 4:3 720X486 for broadcast.

All this because i prefer the scaling in Shake 🙂
It's a piece of cake to do it directly in FCP, but i prefer scaling algorithm in Shake.

BTW, what is supposed to be the most natural scaling filter in Shake ?

Thanks

Antoine

Message was edited by: Antoine Fabi2

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Answer 10

Mar 28, 2009 1:17 PM in response to Antoine Fabi2

I have to tell you then, it wasn't to do with square pixels or otherwise. When I've done this in Shake (I usually use Compressor these days - it seems to scale well), I created a 720x486 color solid, then sized my 1080 HD file and placed it over that...

I dunno what you mean by "natural", I don't know that they're different...

Patrick

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