Handbrake "Storage Geometry" and "Display Geometry" difference

Question

In the latest stable Handbrake release (1.0.1), under the dimensions tab there are two areas with dimension settings "Storage Geometry" and "Display Geometry". Can someone help me understand what these are for? I couldn't find something in the handbrake documentation.

I don't know if I am right, but I guess that the "storage geometry" is the resolution that the end video stream will have, and the "display geometry" is what the container (?) will tell the player to set the display window.

If that's the case, does it make any sense to have a display geometry since all the TVs / Computer screens in fullscreen will override it? And why in the first place we need two different geometry settings?

Answer 1

What you are looking for is DAR / SAR / PAR used in video.  Here

• DAR = Display Aspect Ratio
• SAR = Storage (sample) Aspect Ratio
• PAR = Pixel Aspect Ratio

Historically there was a problem with TVs because they didn't have square pixels like today’s LCD displays (in TVs too). Today video for LCD display should have PAR 1/1.

To answer your question simply:
DAR is saying in what aspect ratio the video is supposed to be displayed. For example, 16/9 for most widescreen videos, and 16/9 = 1.778, this value is calculated by multiplying SAR and PAR.

SAR is saying what aspect ratio the video is. For example 16/9 = 1.778, this is calculated by the frame size. For example, fullHD 1920/1080 = 1.778.

And to clearify this a little bit, PAR is specifying the shape of the pixel. As I said, today we have square pixels, PAL and NTSC TVs have rectangular pixels. With square pixels, DAR and SAR should be the same.

These parameters allow showing the video in the right shape so it won't be squashed or stretched on old CRTs nor new LCD TVs. Much more can be found on the internet; just look for the abbreviations.