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Questions About Native and Modified Resolutions

Posted: Sun Jul 26, 2020 11:03 pm
by Pareto Optimal
Description of problem or question:
Handbrake lists the following in the "Dimensions" tab...
Source 720x480, PAR: 32/27
Width: 720 Height: 362

Output
Display Size: 853x362, Par 32/27

Why does Handbrake change the source rez from 720x480 to 720x362?
Why after changing the rez to 720x362 is the output display size 853x362?
What does Par 32/27 mean?

Note that DVDFab lists the rez of the same DVD movie as 720x304.


Steps to reproduce the problem (If Applicable):

N/A


HandBrake version (e.g., 1.0.0):

1.1.1


Operating system and version (e.g., Ubuntu 16.04 LTS, macOS 10.13 High Sierra, Windows 10 Creators Update):

Windows 10


HandBrake Activity Log ***required*** (see How-to get an activity log)
N/A

Code: Select all

N/A

Re: Questions About Native and Modified Resolutions

Posted: Mon Jul 27, 2020 2:40 pm
by Woodstock
Welcome to the world of anamorphic, where different aspect ratios are encoded to fit a 4:3 storage format.

When you try to put a 16:9 or similar aspect ratio on a DVD, the ways to do it are to shrink the vertical dimension and use black bars ("letterboxing") to cover the empty space, make each pixel wider than it is high (the "PAR" or "pixel aspect ratio"), or a combination of the two. The latter is also referred to as anamorphic format.

Re: Questions About Native and Modified Resolutions

Posted: Mon Jul 27, 2020 2:42 pm
by Rodeo
Woodstock wrote: Mon Jul 27, 2020 2:40 pm Welcome to the world of anamorphic, where different aspect ratios are encoded to fit a 4:3 storage format.
3:2 ;)

Your point is still valid though.

Re: Questions About Native and Modified Resolutions

Posted: Mon Jul 27, 2020 3:17 pm
by JohnAStebbins
More details...

DVD supports 2 and only 2 video display aspect ratios. 4:3 and 16:9.

In each case, the resolution is the same 720x480 (NTSC discs) or 720x576 (PAL discs).

If the pixel aspect of NTSC were 1:1, the display aspect would be 720/480 which reduces to 3:2. You'll note that this is not the same as either of the supported display aspects of DVD, i.e. neither display aspect has 1:1 pixel aspect or square pixels.

In the case of 4:3 display aspect video, the pixel aspect is 8:9 (i.e. pixels are taller than they are wide). And for 16:9 display aspect video, the pixel aspect is 32:27 (wider than they are tall).

In order to represent a video that has a 2.33:1 display aspect (cinema wide screen), they will usually use the 16:9 format, fit the width to 720 and adjust the height by adding black bars top and bottom so that the active portion of the video has a display aspect of 2.33:1.

Re: Questions About Native and Modified Resolutions

Posted: Mon Jul 27, 2020 3:29 pm
by JohnAStebbins
I forgot to answer a couple of your questions.

Why 362 height? HandBrake automatically crops the black bars.

Why 853 width? When the video is played back, the storage resolution is scaled by the pixel aspect to produce the output resolution in order show the video at the correct display aspect. So if the width is 720 and the format is 16:9 (32:27 pixel aspect), the output width will be 720 * 32 / 27 = 853.

And you'll note that 853 / 362 is about 2.33:1. So your original source video was cinema wide screen 2.33:1.