Friday, June 11, 2010

TV Tech in Fast Refresh Mode

Daniel is apparently dead to us. He is flat on his back, watching vivid imagery on his new 240 Hz flatscreen. He says he screwed his back up: I guess we 'll take it it on faith, for he is a most reliable narrator.

The point of this article is an expansion of an earlier comment concerning the inevitable march of entertainment technology. the new high-refresh-rate HDTVs are gaining popularity, but I don't think the general public (or people who think about these things) has really grasped just how important a milestone they represent. In our gadget-centric world, a 120 or 240 Hz TV seems like just another incremental brand improvement, like the a G4 iPhone or a faster Xbox. but I think it's going to prove to be one of the more significant innovations in recent entertainment tech.

Since the invention of moving picture images 114 years ago, the technology of presenting entertainment has been in a state of constant innovation to a single purpose: to create a medium that is as fully immersive as, and indistinguishable from, reality. The first was 35mm film, which for it's first 40-odd years was restrained by photochemical technology (silver halogen emulsion creating black-and-white images) mechanical tolerances (18 frames per second was as fast as hand-cranked cameras could go) and optical limitations (spherical lenses, which needed a frame as close to round as possible to create a sharp image). These limitations did not stop inventors from adding sync sound as quickly as the technology would allow. The frame rate went up to 24, which, again, was a fast as late-20s cameras could run film without flying apart.

Color, which was in experimental mode for decades, was implemented well before it was affordable or practical, recording on 3-strip cameras with beam splitters. Eastman negative film, the first truly practical color film stock, wasn't made available until 1950, which is an indication of just how difficult it was to perfect.

Television came along, with it's crummy low-res image. But what it offered was something movies could not: immediacy. No tickets, no leaving the house: the entertainment came to you. After TV, it all became a race: Color TV, 3D, Stereo audio, CinemaScope, IMAX, Surround Sound, HD. These innovations were all an effort to create a medium that removed the impediment of it's own technological limitations from the viewing experience.

And now we're seeing the two mediums, Film and TV, merge: a 1080 image has nearly all the visual information of a 35mm film frame. Digital Cinema 2K and HD in 1080 24p are almost the same resolution: I can shoot it with my Canon T2i!

But new high-refresh-rate HD monitors address this ongoing rush to reality-perfect imagery in a new way: by increasing the frame rate to a point where persistence of vision becomes purely internal. Video, with it's 60hz interlaced image, has always been more "vivid" than 24 frames-per-second film: now the image processors in high-frequency TVs can take any source at any frame rate, interpolate new in-between frames, and ratchet up the display rate to a point where pretty much anything looks startlingly real.

Remember that "Hertz" is a measure of frequency per second. These new TVs (like Daniel's) display a mind-blowing 240 frames per second. This is ten times faster than motion picture film. Even a state-of-the-art Panavision 35mm camera would explode if it were run this fast, and top recording speed of a Red One Digital camera is 120 fps. This is so fast the screen surface itself vanishes, and the perception of the image on it becomes amazingly vivid. The "frame rate" of human visual perception-- the speed at which imagery is processed in the retina and visual cortex-- is met, and maybe even exceeded, with a fast-rate HDTV. In other words, if you sit close enough to the screen, you're there.

3D is the final hurdle. And I think, current movie-going trends notwithstanding, as long as 3D require the viewer wear big dumb-looking glasses it'll be as much a novelty as it was in the Creature of the Black Lagoon era. And novelties are, by definition, not practical.

1 comment:

  1. I'm with you on 3D though I admit it will be my only excuse to haunt the TV section of electronics stores for the next few years.

    Some day you oughtta take a crack at explaining why film looks so soft on conventional televisions (it's that 3:2 pulldown) that would be understandable. It took me a series of video editing classes to wrap my mind around the concept, but I think you would make short work of it.

    I'm not lying about my back! Though i am lying about because of my back.