All three used to be 60i only due to CRT displays being designed for a 60i signal. Cameras for TV and home videos shot interlaced content. VHS tapes and television broadcasts were interlaced. Movies were shot with progressive cameras and were shown at 24p in theaters with projectors. But they were converted to 60i using 3:2 pulldown for VHS tapes so that you could watch them on your 60i TV at home. Video game consoles and PCs rendered frames progressively but scanning them out using an interlaced RAMDAC to produce a 60i signal.
1. Video games are an interesting topic because video game consoles almost always render the frames in a progressive way (meaning they create progressive content) yet for a long time they used interlaced scanning to output them so that they could be used with televisions. 6th generation video game consoles (sega dreamcast, microsoft xbox, sony ps2, and nintendo gamecube) were the first video game consoles to support both interlaced and progressive scan output. So video game consoles transitioned to progressive scan as they entered the new millennium. Video game consoles still support both interlaced and progressive scan.
2. PCs also render progressively. PC monitors have almost always been progressive scan. But when PCs first emerged in the late 70s and early 80s PC monitors were far too expensive for most users so most users used a 60i TV instead. PC manufacturers realized this and made both interlaced and progressive output standard so that users could choose. By the late 80s monitors were affordable and the PC began transitioning to progressive scan. Today PCs only support progressive scan (unless you have special equipment or older hardware).
3. Movies have always been shot using progressive cameras. Yet just like PCs and video game consoles they had to be converted to interlaced in order to be used with 60i TVs. In the late 1990s DVDs began to replace VHS. VHS only supported 60i content and therefore all movies had to be converted to 60i using 3:2 pulldown before they could be put on a VHS tape. But DVDs supported 24p, 30p, and 60i content. Movies were therefore stored at 24p on DVDs and DVD players supported both interlaced and progressive output. The same is true of BD and BD players.
4. Progressive camcorders for home video also began to take off in the late 1990s. This made it possible to record progressive home videos and store them on DVDs. Progressive camcorders could often record content in either progressive (30p) or interlaced (60i) mode depending on which you preferred. Interlaced would produce smoother video since the shutter fires 60 times per second instead of 30 times per second but it would have combing. Todays video cameras can do 24p, 30p, 60i, and 60p but keep in mind that the DVD standard does not support 60p.
5. TV broadcasts took the longest to make the transition. The transition of TV broadcasts to progressive scan, digital broadcasting, and HD broadcasting all happened at around the same time in 2002-2007. This is because progressive scan and HD broadcasting were practically impossible until the switch to digital broadcasting was made. Today interlaced and progressive TV broadcasts are both common depending on the channel.
6. Of course progressive content is useless without a progressive display system to show it on. The various sources of content listed above did not begin transitioning to support progressive scan until progressive displays were starting to become common. PC monitors almost always supported progressive scan even in the 80s but progressive TVs didn't start to become common until the turn of the millennium, which is why it took so long for everything else to make the transition. This is because even though PC monitors and TVs were both based off of CRT technology PC monitors were much smaller in screen size, which made it a lot easier and cheaper to implement support for progressive scanning. Building a large CRT that can do 60p was extremely difficult.
Today most PC monitors and TVs are LCDs, which are a type of progressive display. Because LCDs can only display progressive content they need to have a deinterlacer built in in order to accept an interlaced signal. The deinterlacer will take the interlaced signal and change it into a progressive signal that the display can display. All HDTVs have a built in deinterlacer. Modern PC monitors do not have a built in deinterlacer, they can only accept progressive signals as input.
|Description||Output||Fluid motion||Interlacing artifacts||Still sharpness||Motion Sharpness||Complexity|
|None||Each frame consists of the odd and even field||30p||Moderate||Yes||Sharp||Sharp||Simple|
|Blend||Blend each pair of odd/even fields together||30p||Moderate||No||Slightly blurry||Slightly blurry||Simple|
|Area||Blend only the mice teeth (only during fast motion), otherwise do nothing||30p||Moderate||No||Sharp||Slightly blurry||Complex|
|Discard||Discard every odd field, stretch height of even fields to 2x||30p||No||No||Very blurry||Very Blurry||Simple|
|Bob/progressive scan||Stretch each field to 2x height||60p||Super||No||Very blurry||Very blurry||Simple|
|Smart interlace||Bob during fast motion, otherwise do nothing and duplicate frames||60p||Super||No||Sharp||Very blurry||Complex|
|Line interpolation||Every blank line is filled by combining the lines above and below it||60p||Super||No||Slightly blurry||Slightly blurry||Simple|
|Motion compensation||Crop and scale each line based on speed of motion||60p||Super||No||Very slightly blurry||Very slightly blurry||Complex|