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Author Topic: 1.50:1 video aspect ratio  (Read 5700 times)

RD James

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1.50:1 video aspect ratio
« on: April 05, 2016, 03:11:47 am »

I have an anamorphic video that's supposed to be played in a 1.50:1 aspect ratio.
How can I set that as the aspect ratio in JRiver?
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blgentry

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Re: 1.50:1 video aspect ratio
« Reply #1 on: April 06, 2016, 08:47:47 am »

I'm most familiar with anamorphic from DVDs.  In a DVD, a 1.78:1 (16:9) frame is horizontally compressed to fit into a 1.33:1 (4:3) frame.  On playback this is reversed.

I'm not sure how MC figures out to do this; there must be a flag somewhere that triggers it because it all works transparently.

What was the source aspect ratio of your video?  What aspect ratio was it squeezed into?  I guess it doesn't really matter unless you can force MC to do a certain "unsqueezing" by telling it a specific ratio. 

Have you considered post processing it with an external tool?

Brian.
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RD James

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Re: 1.50:1 video aspect ratio
« Reply #2 on: April 06, 2016, 09:20:57 am »

It's a 1.78:1 video that should be played back at 1.50:1
JRiver has aspect ratio correction but only a very short list to choose from.
It seems to set a value in the playback info tag, but I can't decipher what they're using to set it at 1.50:1 myself.
 
With 1.33:1 correction I get (6:196612)
With 1.78:1 correction I get (6:589840)
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Hendrik

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Re: 1.50:1 video aspect ratio
« Reply #3 on: April 06, 2016, 09:36:48 am »

That is a compound number to save space, 1.33:1 is 4:3 internally -> 4 + (3 << 16) -> 196612
I suppose we could offer a way to enter custom ratios, it should support any ratio just fine.
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blgentry

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Re: 1.50:1 video aspect ratio
« Reply #4 on: April 06, 2016, 09:48:18 am »

It's a 1.78:1 video that should be played back at 1.50:1

It's reverse anamorphic then?  It needs to be squeezed on playback, not unsqueezed?

Brian.
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RD James

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Re: 1.50:1 video aspect ratio
« Reply #5 on: April 06, 2016, 09:59:42 am »

It's reverse anamorphic then?  It needs to be squeezed on playback, not unsqueezed?
Well I thought anamorphic just meant that it's encoded in a different aspect ratio than the one it's intended to be viewed in, I don't think that being anamorphic requires a particular ratio.
 
That is a compound number to save space, 1.33:1 is 4:3 internally -> 4 + (3 << 16) -> 196612
I suppose we could offer a way to enter custom ratios, it should support any ratio just fine.
Some way to support custom ratios, however it's implemented, would be great.
I wish I understood what you meant by a "compound number" though, as I don't understand what you wrote at all.
I don't know if it's just something that is advanced math, or something basic which I was never taught.
I remember my parents expressing that math had changed the most of any subject from what they were taught at the same age.
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JeTie

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Re: 1.50:1 video aspect ratio
« Reply #6 on: April 06, 2016, 10:46:36 am »

Quote
Some way to support custom ratios, however it's implemented, would be great.
It is - in a way - see Hilton's post on custom resolution not long ago...
2.35:1 Ratio Resolution in MC21 works a treat!
...just do the math  ;)

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Hendrik

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Re: 1.50:1 video aspect ratio
« Reply #7 on: April 06, 2016, 10:49:43 am »

I wish I understood what you meant by a "compound number" though, as I don't understand what you wrote at all.
I don't know if it's just something that is advanced math, or something basic which I was never taught.

<< is left shift, which basically means "multiply by 2 to the power of X". Admittedly is not an operation that comes up in school math often, I guess.
So you could rewrite that to: 4 + (3 * 2^16), which google can even calculate for you now, just replace 4 and 3, say with 3 and 2 for 1.5:1
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RD James

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Re: 1.50:1 video aspect ratio
« Reply #8 on: April 06, 2016, 10:59:55 am »

Ah is it a programmer thing then?
That seems to be working for 1.50:1 (3:2) now, thanks!
 
It's not the most convenient way to set the aspect ratio, but it does the job.
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aproc

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Re: 1.50:1 video aspect ratio
« Reply #9 on: April 07, 2016, 12:10:13 am »

I suppose we could offer a way to enter custom ratios, it should support any ratio just fine.

Yes, it will be really helpful.
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