3 ms·

The DVD format in NTSC regions has 480 pixel vertical resolution. Even the half-century old NTSC spec has more vertical lines (525). I find it amazing that DVDs

by Yaggo 10y ago

The DVD format in NTSC regions has 480 pixel vertical resolution. Even the half-century old NTSC spec has more vertical lines (525). I find it amazing that DVDs are still being sold.

KayEss 10y ago
That's not how it works. Those 525 lines include the beam moving from the bottom right of the screen back to the top left to start to display the next frame (vertical blanking). There are only around 480 lines visible on the screen. The non-image lines is where things like teletext would be transmitted.
United857 10y ago
https://en.wikipedia.org/wiki/Overscan https://en.wikipedia.org/wiki/Overscan
ryandamm 10y ago
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.)
- semi-extrinsic 10y ago
  Don't forget the third analog standard: the French SECAM, short for "System Essentially Counter to the American Model".
- sp332 10y ago
  Even a DVD with a 16:9 image uses non-square pixels, so it encodes 480 "scanlines" but a 4:3 TV with 480 scanlines won't show the full vertical resolution. (If it did, the horizontal would either be squished or cut off at the sides.) A lot of people were buying HDTVs without bluray players because their DVDs looked so much better when they could see the full resolution.

by Yaggo 10y ago

The DVD format in NTSC regions has 480 pixel vertical resolution. Even the half-century old NTSC spec has more vertical lines (525). I find it amazing that DVDs are still being sold.

KayEss 10y ago

That's not how it works. Those 525 lines include the beam moving from the bottom right of the screen back to the top left to start to display the next frame (vertical blanking). There are only around 480 lines visible on the screen. The non-image lines is where things like teletext would be transmitted.

United857 10y ago

https://en.wikipedia.org/wiki/Overscan https://en.wikipedia.org/wiki/Overscan

ryandamm 10y ago

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.)

semi-extrinsic 10y ago
Don't forget the third analog standard: the French SECAM, short for "System Essentially Counter to the American Model".
sp332 10y ago
Even a DVD with a 16:9 image uses non-square pixels, so it encodes 480 "scanlines" but a 4:3 TV with 480 scanlines won't show the full vertical resolution. (If it did, the horizontal would either be squished or cut off at the sides.) A lot of people were buying HDTVs without bluray players because their DVDs looked so much better when they could see the full resolution.