TCL Nxtpaper 11 Plus

[Quoth]

Originally Posted by JSWolf

There was one big difference between US and UK TV back before HD. That was that the refresh rate of UK TVs was worse then that of US TVs. So UK TVs flickered more.

Not noticeable due to phosphor persistence. I worked in Broadcast and AV systems.

USA 480 visible lines (525 lines), 30 Hz for one line high detail, static images with no obvious 1 line horizontal detail 60 Hz (Interlace). Color from 1951 using NTSC so could suffer from severe hue errors. CGA was designed to be compatible. VGA is the non-interlace (progressive). USA used 441 line from 1935 to sometime in 1940s)

Cinema used 24 fps, though eventually they used projectors that showed each film frame twice. So to convert from 24fps (progressive equivalent) Film to USA 30 fps interlaced video a 3:2 pull down scheme was used. This meant with a pan, that two video frames would be from different film frames and you got comb artefacts. It looks terrible. They stored DVDs as 24 fps progressive and the player did pull down. Component video of DVD allowed progressive mode avoiding artefacts.


Most of rest of world except North America and parts of South America: Mostly 625 line (576 visible) 25 fps / 50 Hz. UK used 405 lines (379 approx visible only mono) from 1935 to 1985 (gap 1939-1946) but had also had 625 from about 1962 (just after Ireland) and PAL Colour from about 1967 or so. France and Russia used SECAM. PAL and SECAM solved the NTSC hue issue in different ways.

For 50Hz mains countries the Film was simply played at 25 fps. Later for DVDs they reduced the sound pitch by 24/25ths to get the sound correct. Progressive and Component hardly sold at all because 625 line 25 fps / 50Hz didn't need it. Instead the French developed SCART aka Peritel for RGB connections.

So in real life on real screens there was no extra flicker on 50 Hz countries (the studio lighting and TV power supplies dictated 50Hz or 60Hz), but North American video was 30% less resolution and comb artefact on Telecine panning scenes (Television from Cinema, film to video conversion).

The HD standards started with a Japanese 1125 line based off NTSC, giving 1080 visible lines (hybrid analogue / digital from satellite), so the 720p was designed to avoid the USA film to video artefacts as it's a similar digital bandwidth to 1920 x 1080 interlaced. We now have more digital standards than Analogue and sadly 4K is often only 24 fps. Having 96 fps everywhere would have made more sense.
Movies are often now a higher than domestic 4K at 48 fps at the video camera. Film is far more expensive.

At least one South American country had 30 fps PAL.

And I have seen NTSC 30 fps and PAL 25 fps side by side on professional monitors.