Anamorphic DVD Question

[Lee Christie]

Hey, can I just check something about Anamorphic DVD.

If I have an "anamorphic" disc of a film that was in originally 1.85:1 ratio and it does NOT have black bars, does that mean it's panned&scanned down to 16:9 first, then horizontally squashed to 4:3 (for storing on the disc)... or does it mean that it's been squashed all the way from 1.85:1 to 4:3 without Panning&Scanning?

I think it looks like the former (Pan&Scan to 16:9, then squash to 4:3) but I had thought anamorphic discs didn't Pan&Scan?

Thanks.

[WickyWoo]

Anamorphic on video means it takes advantage of a 16:9 television, it does not refer to the photographic process, though the principles are the same

[Lee Christie]

Originally Posted by WickyWoo

Anamorphic on video means it takes advantage of a 16:9 television, it does not refer to the photographic process, though the principles are the same

So all it means is that it's intended to be viewed on 16:9 rather than 4:3 so it's either going to be Pan&Scan 16:9 or Letterbox 16:9... as opposed to Pan&Scan 4:3 or Letterbox 4:3... and in this particular case it'll likely be Pan&Scan 16:9 since there are no black bars?

[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.

For a 4:3 TV, the DVD player would reduce the 480 pixel height of the frame by 0.75x (480 x 0.75 = 360 pixels,) add 120 pixels more of black (360 + 120 = 480) (60 below and 60 above, letterboxing it), the 1.85 image ends up being 355 x 720 inside a 480 x 720 frame, and it's sent that way to the 4:3 TV, which displays the newly letterboxed 480 x 720 frame so it looks proper 1.85 letterboxed.

No Pan & Scan

[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.