4K / UHD / 2160p 映画

What does 4K actually mean?

4K — also sold as Ultra HD (UHD) or 2160p — is a picture 3840 pixels wide and 2160 tall: four times the pixel count of Full HD. Strictly speaking, "4K" is a cinema term (4096×2160 in DCI theaters) while UHD is the slightly narrower consumer version, but in practice the labels are used interchangeably on TVs, streaming tiers and discs.

Resolution is only half the story

What makes modern 4K releases look dramatic usually isn't the pixels — it's what ships alongside them. HDR (High Dynamic Range), in formats like HDR10 and Dolby Vision, widens the range between the darkest and brightest parts of the image; wide color gamut brings richer, more accurate color. A well-mastered 1080p picture with HDR can look better than flat 4K. When people say a film "looks incredible in 4K," they're usually reacting to HDR as much as resolution.

When is 4K worth it?

• Screen size and distance: below roughly 55 inches, or from a normal couch distance, the resolution jump over 1080p is hard to see — HDR remains visible at any size.
• Bandwidth: streaming 4K well takes about 15–25 Mbps; UHD Blu-ray discs run far higher bitrates and remain the gold standard for picture quality.
• Source material: films shot or mastered in native 4K benefit most; older titles upscaled from 2K masters gain little sharpness, though HDR regrades can still transform them.

YTS is a streaming and download platform for movies and complete TV series & seasons in every quality tier — and this page covers the very top of it: 4K UHD.

Below: spectacle-driven films — the kind of cinematography 4K exists for — followed by the all-time greats most often remastered in UHD.