Definition of 540p

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alehel
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Joined: Wed Feb 14, 2007 11:08 am

Definition of 540p

Post by alehel »

This question struck me today as I was encoding my newly purchased Batman begins blu-ray. When encoding for my computer, I always encode as 540p as I can't really tell the difference between that and higher when watching on my laptop, which is what these encodes are for. The thing is, the batman film on bd has black bars on the top and the bottom due to the fact that the aspect ratio is in fact 2.4:1. This means that with the black bars the film is 960x540. Once cropped I'm left with 960x400. Now my question is this. Would a 540p rip of this movie be 960x400 or would it be 1296x540? I ask as it would be nice to get a grasp of what these definitions mean for movies that aren't 16:9.
jamiemlaw
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Re: Definition of 540p

Post by jamiemlaw »

Good question. Short answer: 960x400.

For movies wider than 16:9, a 540p encode would be defined as one that's 960 pixels wide. For anything less, it is based on height, as you'd expect.

At least, that's how I treat it.
alehel
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Re: Definition of 540p

Post by alehel »

That's what I suspected. I downloaded the 1080p trailer from apples website and sure enough, it wasn't 1080 high, but it was 1920 wide.
mduell
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Re: Definition of 540p

Post by mduell »

540p, if it was a standard (I don't see it defined by ATSC or DVB), would be 540 pixels of vertical resolution.

FWIW I'd recommend reencoding at the native resolution of your laptop rather than downscaling then upscaling. Just raise the rate factor a couple points to hit the same file size.
alehel
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Re: Definition of 540p

Post by alehel »

mduell wrote:540p, if it was a standard (I don't see it defined by ATSC or DVB), would be 540 pixels of vertical resolution.
I've seen people on other forums talk about 540p. I just presumed it was a standard.
mduell
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Re: Definition of 540p

Post by mduell »

Given the existence of 480p, 576p, 720p, 1080p, etc it's no great stretch for anyone to extend the convention to figure out what you're talking about.
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