DVD's PAR and output display size explanation in Handbrake

[Superfrank]

Hi there! I'm using Handbrake, to rip my dvd collection and I've done a lot of searching and think I have a basic understanding of how it all works with regard to pixel aspect ratio and screen aspect ratio, display resolution and so on, but I have gaps in my knowledge and understanding so as I'm talking here forgive me if I get it completely and utterly wrong on any or all accounts (and please correct me so I can learn).

Anyway I have opened the source of a dvd I ripped to my comp with handbrake and it says on the picture tab using one of the standard presets that the source is:

720x576 PAR 16/15

Width and height is then set as 720x540

Anamorphic is set to automatic, modulus is 2, however this dvd's content is 4:3 tv shows so I believe I don't need anamorphic but can safely leave it set to automatic.

Lastly it has the output showing as:

Display Size: 720x540, PAR 1x1

(This is before any cropping has been applied).

Now as far as I can understand, the dvd uses non-square pixels, hence the PAR is 16/15 and the resolution is 720x576. Am I therefore correct in thinking that hand brake has automatically adjusted the resolution to 720x540 because that is in essence identical to the content on the dvd when it has had its pixels converted to square pixels, making the PAR 1x1? Cheers!

[jagabo]

Yes, that's exactly how it works:

DAR = PAR * FAR

DAR is the final displayed aspect ratio, PAR is the pixel aspect ratio, and FAR is the frame aspect ratio.

DAR = 720:576 * 16:15
DAR = 720 / 576 * 16 / 15
DAR = 1.33...

720/540 is also 1.33... But it doesn't retain the full resolution of the source since the height has been reduced from 576 lines to 540 lines.

Keep in mind that when watching the original DVD upscaled to 1920x1080 -- the DVD isn't first reduced to 720x540 then upscaled to 1440x1080. It goes directly from 720x576 to 1440x1080.

[Superfrank]

Ace, thanks very much for the help!

[Cornucopia]

Also, since the vertical resolution is discreet in the sampling, it should be preserved in the resizing equation.
So that would give you 768x576 for 4:3 and 1024x576 for 16:9.

Scott