Doom9's Forum - View Single Post - Resolutions, Aspect Ratios And The ITU-R BT.601 Standard

Loul · 9th February 2003, 20:38

I finally went for another test.

I have this Pink Floyd - The Wall dvd.
And in the menus you got those pages where you have to select between 4 options. One of those was with 4 arrows symetrically drawn like that :

..................^.........
..................|.........
...............<-...->......
..................|.........
..................\/........

(well my drawing ain't perfect but I think you got the idea).

The arrows were significally large enough (between 100 and 130 pixels).

What I did is that I captured the picture I got with Power DVD and made some edition of it in a Photoshop like software.

I took one of the "horizontal arrow" and made it turn by 90° (then by another 180° to check on the other one).
And it fitted quite perfectly on the vertical arrows.

Then I "compressed" the image quite like the ITU checkbox does (by 2.5%) and did the same test again.
This time the Vertical arrows were significally shorter than the horizontal one.

I attached a jpeg version of this image so you could have a clearer idea of what I did (if a moderator could approve this attachment, thank you).

The learning of this test is, imho, that the Power Dvd resizing method gives a correct display aspect ratio.
Hence according to this, the correct option would be to leave the ITU checkbox unchecked.

If you have better pictures on other dvds to do the same test, please do it to check if you have the same results.

I don't want to bother anyone especially the author(s) of gordian knot whom I'd like to thank on this occasion.
I just wanted to see what was the correct thing to do to do a proper encode with this test.

I hope this will prove useful or at least interesting.

9th February 2003, 20:38	#12 \| Link
Loul Registered User Join Date: Dec 2002 Location: Paris, France Posts: 37	I finally went for another test. I have this Pink Floyd - The Wall dvd. And in the menus you got those pages where you have to select between 4 options. One of those was with 4 arrows symetrically drawn like that : ..................^......... ..................\|......... ...............<-...->...... ..................\|......... ..................\/........ (well my drawing ain't perfect but I think you got the idea). The arrows were significally large enough (between 100 and 130 pixels). What I did is that I captured the picture I got with Power DVD and made some edition of it in a Photoshop like software. I took one of the "horizontal arrow" and made it turn by 90° (then by another 180° to check on the other one). And it fitted quite perfectly on the vertical arrows. Then I "compressed" the image quite like the ITU checkbox does (by 2.5%) and did the same test again. This time the Vertical arrows were significally shorter than the horizontal one. I attached a jpeg version of this image so you could have a clearer idea of what I did (if a moderator could approve this attachment, thank you). The learning of this test is, imho, that the Power Dvd resizing method gives a correct display aspect ratio. Hence according to this, the correct option would be to leave the ITU checkbox unchecked. If you have better pictures on other dvds to do the same test, please do it to check if you have the same results. I don't want to bother anyone especially the author(s) of gordian knot whom I'd like to thank on this occasion. I just wanted to see what was the correct thing to do to do a proper encode with this test. I hope this will prove useful or at least interesting. Last edited by Loul; 9th February 2003 at 20:46.