4K resolution
4K resolution is a video resolution of about 4,000 pixels across, most commonly 3840 x 2160 pixels for TVs and streaming, also called Ultra HD (UHD). It has four times as many pixels as 1080p Full HD. Cinema 4K, used in film production, is slightly wider at 4096 x 2160 pixels.
Why it matters
4K is a premium feature that viewers will pay for, especially for films and live sports on large TVs. It also has real costs: 4K files need several times the bitrate of 1080p, which raises encoding, storage and delivery bills. Many services limit 4K to top-tier plans for this reason. That makes a 4K tier easier to justify on FastPix: Standard encoding is free up to 4K, so the tier adds storage and the minutes viewers actually watch, not an encoding bill, and you can cap resolution on titles where 4K is not worth it.
How it works
- Content is shot or mastered at 3840 x 2160 pixels or higher.
- It is encoded with efficient codecs, such as HEVC or AV1, to keep the bitrate manageable.
- The 4K version sits at the top of the bitrate ladder, with lower levels below it.
- Players on 4K screens with fast connections pick it; others fall back automatically.
Is 4K the same as UHD?
In everyday use, yes: 4K and UHD both usually mean 3840 x 2160 pixels on TVs and streaming services. Strictly, cinema 4K (DCI 4K) is 4096 x 2160, slightly wider. Consumer TVs and streaming services use the 3840 x 2160 UHD version and market it as 4K.
How much bandwidth do you need for 4K streaming?
4K streaming usually needs a steady connection of at least 15 Mbps, which is what Netflix recommends, and some services ask for more. Efficient codecs such as HEVC and AV1 need less than older H.264. Fast-moving sports or HDR content may need more. Slower connections usually get a lower resolution instead.
4K vs 1080p: is it worth it?
4K is worth it on large TVs viewed fairly close, where its extra detail is visible. On phones and small laptops, most people cannot see much difference from 1080p. For a business, 4K makes sense for premium films, nature content and sports, but adds cost for little gain in short clips or lectures. Each 4K minute watched costs $0.002173 on FastPix, so the price of a 4K tier can be set from expected viewing.
Where it's used
OTT services offer 4K in premium plans, and live sports streamers use it so fans on big TVs see sharper action. It costs more to encode, store and deliver.
By the numbers
- ITU-R Recommendation BT.2020, first published in August 2012, defines 3840 x 2160 as one of two UHDTV resolutions. (Rec. 2020 (Wikipedia))
- YouTube recommends 35 to 45 Mbps for 4K SDR uploads at 24 to 30 fps. (YouTube recommended upload encoding settings)
