Anamorphic DVD Question

[Lee Christie]

Originally Posted by Deciazulado

Ok you have a 1.85 movie. On a NTSC disc that is coded for 16:9 displays that image would be 473 pixels tall by 720 pixels wide inside the DVDs 480 x 720 frame.

For a 16:9 TV the DVD would send that to the 16:9 TV and the display would unsquish horizontally that 480 pixel tall frame, so it looks proper 1.85.

I'm not sure I understand. 720x473 wouldn't make it 1.85. If a 1.85 picture and a 16:9 picture share a common width, the 1.85 would be 96.096096% (that's 16:9/1.85) of the height of the 16:9, making it 461px (for NTSC). Can you explain the calculation that got you to 473? But anyway, even if I'm wrong... the point is it's less than 480 and so should have SOME rows as black bars, but it has zero, it fills the 16:9 screen.

By the way it's PAL not NTSC, but you weren't to know that because I neglected to mention, sorry.

[WickyWoo]

Most 1.85:1 films are shot open matte, so they open it up just a little bit to 1.78:1. The difference is 4%, less than most people lose in overscan

[Deciazulado]

Originally Posted by Lee Christie

I'm not sure I understand. 720x473 wouldn't make it 1.85. If a 1.85 picture and a 16:9 picture share a common width, the 1.85 would be 96.096096% (that's 16:9/1.85) of the height of the 16:9, making it 461px (for NTSC). Can you explain the calculation that got you to 473? But anyway, even if I'm wrong... the point is it's less than 480 and so should have SOME rows as black bars, but it has zero, it fills the 16:9 screen.

By the way it's PAL not NTSC, but you weren't to know that because I neglected to mention, sorry.

That is because NTSC (and PAL) don't use "square pixels". So in 4:3 NTSC 486 x 710.85 pixels = 1.3333 and in 4:3 PAL 576 x 702 = 1.3333

On DVD's mpeg-2 the "pixel frame" size is 480 x 720 (NTSC) and 576 x 720 (PAL) (no matter if the image inside is coded for 4:3 displays or 16:9 displays). If they were counted as square pixels the ratios would be respectively 480 x 720 = 1.50 to 1 for NTSC and 576 x 720 = 1.25 to 1 for PAL. But as I said, NTSC and PAL don't use square pixels. All images recorded on DVDs are "anamorphic" (changed form) because they're not "recorded" in the shape they must be seen or displayed.