What HDR Actually Changes
Standard dynamic range (SDR) video uses 8-bit color depth and is mastered for a maximum of 100 nits of brightness. HDR content uses 10-bit (or 12-bit for Dolby Vision) color depth and is mastered for peak brightness levels of 1,000–10,000 nits. The increased bit depth allows more gradations between black and white, eliminating banding artifacts in gradients. The higher peak brightness allows specular highlights (sunlight reflections, flames, explosions) to appear at dramatically higher luminance than the average image level.
HDR metadata tells the display how bright the content was mastered and how to map those values to the display's actual capabilities — a process called tone mapping.
HDR Format Comparison
| Format | Metadata Type | Bit Depth | Licensing | Where You See It |
|---|---|---|---|---|
| HDR10 | Static (per title) | 10-bit | Open, free | Netflix, Disney+, Amazon, most services |
| HDR10+ | Dynamic (per scene) | 10-bit | Open, free | Amazon, Samsung TVs |
| Dolby Vision | Dynamic (per frame) | 12-bit | Proprietary, licensed | Netflix, Apple TV+, Disney+, Vudu |
| HLG | None (backward compatible) | 10-bit | Open, free | Broadcast TV, YouTube, BBC iPlayer |
Bandwidth Impact of HDR
HDR metadata itself is tiny — a few kilobytes per hour. The bandwidth increase from SDR to HDR comes primarily from the higher bit depth (10-bit vs 8-bit), which results in approximately 10–20% larger file sizes for the same resolution. In practice, a 4K HDR stream requires roughly 20–25 Mbps versus 15–20 Mbps for 4K SDR on the same codec. The resolution (4K) is by far the dominant bandwidth driver; HDR is incremental.
Netflix's recommended 25 Mbps for 4K UHD covers both HDR and SDR 4K content. You do not need a separate, faster internet plan for HDR.
What Hardware You Need for HDR
The entire chain must support HDR for it to be delivered:
- Streaming service: Must offer HDR content and your subscription tier must include it (Netflix requires Standard with Ads or higher for HDR on select titles; Netflix Premium for 4K HDR).
- Streaming device or smart TV app: Must support the HDR format. Apple TV 4K, Roku Ultra, Fire TV Stick 4K Max, and most modern smart TVs support HDR10 and Dolby Vision.
- HDMI cable: Must be HDMI 2.0 or 2.1 to carry 4K HDR signals. HDMI 1.4 cables can carry 4K at 30fps but may not pass HDR metadata correctly.
- Display: Must be HDR-certified (VESA DisplayHDR, HDR10, or Dolby Vision certified). Peak brightness of 600+ nits delivers a meaningful HDR experience; 1000+ nits is ideal.
Frequently Asked Questions
Why does my TV show HDR but the picture doesn't look different?
Three likely causes: your TV's peak brightness is too low to show a meaningful HDR difference (budget HDR TVs under 400 nits tone-map the signal down to SDR levels); the content may not be genuinely HDR-mastered; or the HDMI cable is stripping HDR metadata (use HDMI 2.0+). A TV with 600+ nits shows a perceptible HDR difference on well-mastered content.
Is Dolby Vision always better than HDR10?
On a capable Dolby Vision-certified display, dynamic frame-by-frame metadata can look noticeably better than HDR10's static metadata — particularly in scenes that mix very bright and very dark elements. On mid-range LCDs, the difference is often minimal. Amazon uses HDR10+ (also dynamic, no Dolby license fee) instead of Dolby Vision for their content.