From Wikipedia's article on NTSC: "483 scan lines make up the visible raster" The 525 includes a lot of other stuff. Easy mistake because PAL shows 576 lines

From Wikipedia's article on NTSC: "483 scan lines make up the visible raster" The 525 includes a lot of other stuff. Easy mistake because PAL shows 576 lines (out of 625), but only at 25 full frames / 50 interlaced half-frames per second as opposed to 30p/60i for NTSC. (PAL DVDs are also 576.) While they're all constrained by the scanline in the vertical direction, the analog standards are resolution-limited in the horizontal raster by the bandwidth / frequency response of your signal chain; I've seen beta-derived analog NTSC that's gorgeous, far better than DVD. Especially on a really well-corrected CRT monitor (really!). The decision to go to an even 480p for DVD probably derives from the 8x8 pixel blocks of the MPEG-2 compression. Having raster dimensions that are evenly divisible by 8 is a good thing for a lot of these block-based codecs; I believe MPEG-2 couldn't go below 8x8 (h.264 can accommodate smaller and non-square macroblocks, though). That said, there's a nugget of truth in your comment. When we go to digital, we often get better average fidelity, but worse maximum fidelity. A beautiful analog system can be really great. Maybe in twenty years we'll have a hipster revival of 70mm film prints? It's the new vinyl... (I'm being a little tongue-in-cheek; reports from Ang Lee's latest movie are that the digitally-captured 4096p120 stereo 3D is better than the real thing. I saw 30-year film industry veterans were walking out of a test screening shaking their heads in disbelief -- I couldn't get in because the line was around the hall.)