a DV tech/trivia question?

TheHappyFriar wrote on 4/1/2003, 10:32 PM

I've always wondered this since I starting working with DV (well, not DV technicaly... Analog capture at 720x480 on a Matrox RT2500)... Why does DV have a different pixel ratio then normal NTSC? They look the same on TV, and I see no difference between a 640x480 video and 720x480 video when played back on YV, so why?

Comments

Brazilian wrote on 4/1/2003, 10:52 PM

NTSC has no pixel aspect ratio per se, actually.. since NTSC is analog, there are no pixels. All digital forms are sampled, and can be done so at any number of resolutions.

The SD standard in the US for ditital production is ITUR-601 which defines an active frame size of 720x486, which if you do the math as 4x3, is non-square. DV and MPEG2 for DVD use the same pixel aspect ratio as 601 but whacks 6 lines veritcally to make it 720x480.

Why 720x480 and not 640x480? Why not? :) You just get more horizontal resolution.

Chienworks wrote on 4/2/2003, 5:32 AM

The extra horizontal pixels also help anamorphic widescreen to look better.