Streaming Technology
HD vs Full HD vs 4K: What the Resolutions Really Mean
720p, 1080p, 4K: what each resolution means, how much difference you will see at your screen size and distance, and why bitrate matters as much as resolution.
HDR — high dynamic range — is one of the most visible improvements in modern TV pictures, often more striking than the jump from Full HD to 4K. It is also one of the most confusing, because several competing formats exist and settings can make HDR look worse rather than better. This guide explains the formats and how to get HDR working properly.
What HDR does
Standard dynamic range (SDR) video was designed around the capabilities of older TVs. HDR expands the range between the darkest and brightest parts of the image and, together with wider colour support, allows:
- Brighter highlights, such as sunlight or reflections.
- More detail in shadows.
- More saturated, realistic colours.
The result depends heavily on the TV: an HDR signal on a TV with limited brightness and contrast will look only modestly different from SDR.
The main HDR formats
| Format | Metadata | Notes |
|---|---|---|
| HDR10 | Static (one set of values for the whole title) | The baseline open standard; supported by virtually all HDR TVs |
| HDR10+ | Dynamic (scene-by-scene) | Royalty-free extension of HDR10; supported by some TV brands and services |
| Dolby Vision | Dynamic | Proprietary; widely used by streaming services; requires support in TV and device |
| HLG (Hybrid Log-Gamma) | None needed | Designed for broadcast and live TV; compatible with SDR displays |
Static vs dynamic metadata
Metadata tells the TV how to display the HDR image. With static metadata (HDR10), the same instructions apply to the whole film. With dynamic metadata (HDR10+ and Dolby Vision), instructions can change scene by scene, which helps TVs with limited brightness display each scene more appropriately.
HLG for live content
HLG was developed for broadcasting. It encodes HDR in a way that SDR TVs can still display acceptably, making it practical for live channels and sport where one signal must serve everyone.
What you need to watch HDR
- An HDR-capable TV that supports the format being streamed.
- A device that supports the same format — the TV’s apps, or a streaming stick or box.
- An HDMI connection and cable that support HDR (typically HDMI 2.0 or newer, with a High Speed or Ultra High Speed cable).
- HDR content from a service and plan that offer it.
If a format is not supported somewhere in the chain, the device typically falls back to HDR10 or SDR.
Getting HDR settings right
Enable HDR on the HDMI input
Many TVs require you to enable an enhanced or “UHD colour” mode for each HDMI port before they will accept HDR from an external device. Look for options such as HDMI UHD Color, Input Signal Plus, HDMI Ultra HD Deep Colour or Enhanced format.
Match dynamic range on the streaming device
Devices that output HDR all the time convert SDR content to HDR, which can look wrong. Where available, enable an option that switches to HDR only for HDR content — on Apple TV this is Match Dynamic Range; other devices have similar settings. See our Apple TV setup guide for an example.
Choose an appropriate picture mode
TVs have separate picture settings for HDR. Movie, Cinema or Filmmaker Mode usually give the most accurate result. Very bright “vivid” modes tend to clip highlights.
When HDR looks wrong
| Symptom | Possible cause | Try |
|---|---|---|
| Too dark | Normal for some mastering; or room too bright | Use a brighter HDR mode designed for daytime, or adjust room lighting |
| Washed out | SDR being converted to HDR, or HDMI input not in enhanced mode | Enable match dynamic range; enable enhanced HDMI format |
| Flickering or black screen | Cable or port bandwidth | Use a certified cable and the TV’s full-bandwidth HDMI port |
| Colours look oversaturated | Vivid picture mode | Switch to Movie or Filmmaker Mode |
Does HDR need more bandwidth?
HDR adds only a modest amount of data compared with the resolution and bitrate of the stream. It is usually delivered alongside 4K, so the bandwidth needed is mostly determined by 4K itself. See internet speed for streaming.
Is HDR worth caring about?
On a good TV, HDR can make a bigger visible difference than 4K resolution. On an entry-level HDR TV with limited brightness, the improvement is smaller. If you are comparing TVs or devices, check which formats they support; HD vs Full HD vs 4K and video codecs explained cover the other parts of the picture-quality puzzle.
Summary
HDR10 is the universal baseline, HDR10+ and Dolby Vision add scene-by-scene optimisation, and HLG serves live broadcast. To enjoy HDR, every link — TV, device, cable, settings and content — must support it, and settings like enhanced HDMI format and match dynamic range make the difference between impressive and disappointing.