FORTUNE — Television manufacturers are desperate to find something to jolt their moribund market. Global TV shipments declined 6% in 2012, according to NPD DisplaySearch. And this year isn’t likely to be much better. Now Sony (SNE), Samsung, Toshiba, and LG are turning to so-called 4K ultra-high-definition sets. They feature incredibly crisp images with several times the resolution of today’s top-end devices. Prices are well over $10,000, for the time being. In other words, here we go again.
Display
Current high-definition sets produce images made of 2 million individual points of light, called pixels. New 4K TVs — named for the number of vertical lines on a screen — bump up the number of pixels to more than 8 million. Old HDTVs clarified the details of an actor’s face, but 4K TV also sharpens the details of his surroundings. In other words, the picture is not only sharper but has more depth.
Form
Several 4K models employ organic light-emitting diodes, or OLEDs, to produce brighter images. Blacks are blacker, and colors bolder — the holy grail of television imaging. And because such sets don’t require a separate built-in light source to illuminate the picture, as many of today’s flat panels do, OLED displays are much thinner and more flexible. One Samsung model is actually slightly curved.
Content
There are few sources of 4K video. The content that does exist takes up huge amounts of space. For instance, the 4K documentary TimeScapes — a 48-minute ode to the people and scenery of the American Southwest — consumes a whopping 330 gigabytes. (A typical Blu-ray film is more than 10 times smaller.) Netflix (NFLX) and Samsung are currently working to trim gargantuan files.
This story is from the February 25, 2013 issue of Fortune.