In digital terms, NTSC content was produced in 640x480, and PAL content in 768x576.
No. Digital NTSC video was 720x480.
No. Digital video has always been produced in many different resolutions, including 640x480 (NTSC), 720x480 (NTSC), 720x576 (PAL) and 768x576 (PAL) being some of the most typical. There is no single resolution.
The purpose of my comment, which you took outside of context, was to explain the bandwidth difference in digital terms. PAL has higher video bandwidth which also translates into slightly better horizontal resolution, so using more pixels for it makes sense. 640x480 (NTSC) and 768x576 (PAL) happen to use square pixels for 4:3 material, which makes them less confusing. Their horizontal pixel count difference also roughly captures the analog performance difference.
Towards end of the SD video era, most formats and processed converged to 720x480 or 720x576. Neither have square pixels.
Sorry, I know what I’m talking about, and you’re also wrong about the history of the resolutions.
Don’t confuse the square-pixel display resolutions on computers with the actual resolutions used in NTSC and PAL digital video formats. FYI, the “display” pixel ratios are called the “display aspect ratio” and the ones actually stored are the “storage aspect ratio”.
The first digital video format
ever on the market was D1 videotape (1986), which used 720x486 for NTSC and 720x576 for PAL, in both cases a storage aspect ratio of 5:4. Only much later, when digital video
distribution on computers became common, did any square-pixel formats become commonplace. But in production, the actual native storage aspect ratios are used.
768x576 is the
display resolution when scaling the non-square storage pixels of 720x576 up to 4:3 aspect ratio using square pixels and keeping the 576px dimension untouched. Many computer video playback apps don’t report the storage resolution, instead displaying the already-scaled display resolution, which is why people mistakenly think that 640x480 NTSC and 768x576 PAL are a thing. It didn’t help that when converting to most compressed video formats, the compressor often scales to square pixels and then compresses that. But again, those were never the production resolutions.
Note that the resolutions are defined in broadcast standards, like
SMPTE 259M. “There is no single resolution” is fundamentally incorrect.
If you calculate the horizontal x vertical resolution x frame rate to get a pixel rate per second, you’ll find that 720x486x29.97 and 720x576x25 are very, very similar. 768x576x25 would require about 25% more.
(Many later digital video standards did adopt 720x480 for NTSC, dropping 6 lines to get a number cleanly divisible by 8. 576 is already divisible by 8 so it was left alone.)