> I often get comments saying “[720x480]’s not not a 16:9 resolution” or “that’s not real 480p”, but “480p” encapsulates a range of resolutions and aspect ratios and 720×480 is the resolution the Xbox considers to be 480p (so take it up with Microsoft, not me…).
“The February 1980 note further suggested that the number of samples per active line period should be greater than 715.5 to accommodate all of the European standards active line periods. While the number of pixels per active line equal to 720 samples per line was not suggested until the next note, (720 is the number found in Rec. 601 and SMPTE 125), 720 is the first value that “works”. 716 is the first number greater than 715.5 that is divisible by 4 (716 = 4 x 179), but does not lend itself to standards conversion between 525-line component and composite colour systems or provide sufficiently small pixel groupings to facilitate special effects. Arguments in support of 720 were provided in additional notes prior to IBC in September 1980.
[…]
As noted above, Rec. 601 provided 720 samples per active line for the luminance channel and 360 samples for each of the colour-difference signals.
When the ITU defined HDTV, they stipulated: ‘the horizontal resolution for HDTV as being twice that of conventional television systems’ described in Rec. 601 and a picture aspect ratio of 16:9. A 16:9 picture ratio requires one-third more pixels than a 4:3 picture ratio. Starting with 720, doubling the resolution to 1440 and adjusting the count for a 16:9 aspect ratio leads to the 1920 sample per active line defined as the basis for HDTV [9].
Accommodating the Hollywood and computer communities’ request for ‘square-pixels’, meant that the number of lines should be 1920 x (9/16) = 1080.
Progressive scan systems at 1280 pixels per line and 720 lines per frame are also a member of the ‘720-pixel’ family. 720 pixels x 4/3 (resolution improvement) x 4/3 (16:9 aspect ratio adjustment) = 1280. Accommodating the Hollywood and computer communities’ request for ‘square-pixels’, meant that the number of lines should be 1280 x (9/16) = 720.
Therefore, most digital television systems, including digital video tape systems and DVD recordings are derived from the 4:2:2 basic standard format. The 720 pixel-per-active-line structure became the basis of a family of structures (the 720-pixel family) that was adopted for MPEG-based systems including both conventional television and HDTV systems.”
It's true that 4:3 is also anamorphic on DVD since the 720×480 MPEG transport is a 3:2 resolution. I think it's a pretty elegant compromise halfway between 4:3 and 16:9 so both can look equally decent. A lot of DVD video has a program area of 704×480, and most DVD rippers don't differentiate so you wind up with 8px pillarbars and very slightly wrong dimensions: https://forum.videohelp.com/threads/269644-DV-to-704x480-or-...
DVD-sourced media can look great on modern displays if you…
– Encode at 720×540 slash 960×540 to avoid throwing away that extra horizontal detail, as most encoders do by crunching 4:3 video down to 640 (with pillarbars lol) × 480. Also to take advantage of integer-scaling to 1080/2160/etc which is especially beneficial on cheap TVs with crappy scalers.
— Deinterlace to double-FPS (60000/1001 fields-per-second for color NTSC) to avoid throwing away the actual benefit of interlacing in that sweet sweet motion detail. Most rippers crunch it down to 30FPS like Handbrake leads people to do.
— Convert the video to HD-standard color primitives, again to avoid cheap displays' poor treatment of SD colorspace. Chroma-subsampled video is already a little washed out by design and this can compound to make it look even worse.
Take it up with some ITU dudes in the 1970s actually: https://tech.ebu.ch/docs/techreview/trev_304-rec601_wood.pdf
“The February 1980 note further suggested that the number of samples per active line period should be greater than 715.5 to accommodate all of the European standards active line periods. While the number of pixels per active line equal to 720 samples per line was not suggested until the next note, (720 is the number found in Rec. 601 and SMPTE 125), 720 is the first value that “works”. 716 is the first number greater than 715.5 that is divisible by 4 (716 = 4 x 179), but does not lend itself to standards conversion between 525-line component and composite colour systems or provide sufficiently small pixel groupings to facilitate special effects. Arguments in support of 720 were provided in additional notes prior to IBC in September 1980.
[…]
As noted above, Rec. 601 provided 720 samples per active line for the luminance channel and 360 samples for each of the colour-difference signals.
When the ITU defined HDTV, they stipulated: ‘the horizontal resolution for HDTV as being twice that of conventional television systems’ described in Rec. 601 and a picture aspect ratio of 16:9. A 16:9 picture ratio requires one-third more pixels than a 4:3 picture ratio. Starting with 720, doubling the resolution to 1440 and adjusting the count for a 16:9 aspect ratio leads to the 1920 sample per active line defined as the basis for HDTV [9].
Accommodating the Hollywood and computer communities’ request for ‘square-pixels’, meant that the number of lines should be 1920 x (9/16) = 1080.
Progressive scan systems at 1280 pixels per line and 720 lines per frame are also a member of the ‘720-pixel’ family. 720 pixels x 4/3 (resolution improvement) x 4/3 (16:9 aspect ratio adjustment) = 1280. Accommodating the Hollywood and computer communities’ request for ‘square-pixels’, meant that the number of lines should be 1280 x (9/16) = 720.
Therefore, most digital television systems, including digital video tape systems and DVD recordings are derived from the 4:2:2 basic standard format. The 720 pixel-per-active-line structure became the basis of a family of structures (the 720-pixel family) that was adopted for MPEG-based systems including both conventional television and HDTV systems.”