Concept · Video remastering
SDR vs HDR: What's Actually Different (and How to Convert SDR to HDR)
Every "4K" screen sells you HDR, but most of the video on it is still SDR. Here is what the two formats actually differ on — and what it takes to get a real HDR master out of an SDR source.
TL;DR
SDR vs HDR at a glance
SDR was designed for CRT-era displays; HDR assumes a modern panel can show far more brightness, a wider color gamut, and smoother gradients. Everything below flows from those three gaps.
| Dimension | SDR | HDR |
|---|---|---|
| Peak brightness | ~100 nits | 1,000–10,000 nits |
| Color space | BT.709 (Rec.709) | BT.2020 (wider primaries) |
| Bit depth | 8-bit | 10-bit (and up) |
| Colors | ~16.7 million | 1 billion+ |
| Metadata | None (static picture) | Static (HDR10) or dynamic (HDR10+/DV/HLG) |
Why HDR content is scarce
Native HDR production is expensive: HDR cameras, HDR grading suites, and HDR delivery pipelines are still a fraction of the industry. Meanwhile, decades of SDR libraries sit unused — archive footage, catalog dramas, short-form content — all technically viewable, none of it HDR.
That gap is exactly what SDR-to-HDR conversion exists for. It is not a substitute for shooting HDR. It is the only practical way to make an existing SDR library HDR at scale.
Under the hood
What SDR2HDR conversion actually does
A conversion model lifts each scene along three dimensions, in plain terms:
1. Brightness — stretches the 0.1–100 nit range toward the full HDR range so highlights and shadows both breathe.
2. Color — expands BT.709 toward BT.2020 while preserving hue relationships, so skin tones and brand colors do not shift.
3. Bit depth — rebuilds gradients in 10-bit to remove the banding SDR compression leaves behind.
- Per-scene analysis, not a global curve
- 10-bit output with HDR10 metadata
- Async job API for whole libraries
- Postman collection included
How do the options compare?
| Path | What it does | Best for |
|---|---|---|
| Native HDR capture | Shot and graded in HDR from day one | New productions |
| SDR2HDR conversion | AI relights SDR footage into HDR range | Existing libraries, catalogs, archives |
| AI upscaling | Adds resolution, not dynamic range | SD/HD content that is already HDR |
| Combined | Upscale first, then convert to HDR | Full legacy remaster |
What about HDR10, HDR10+, Dolby Vision and HLG?
HDR10 is the baseline: static metadata, universal device support, free to use. HDR10+ and Dolby Vision add dynamic (per-scene) metadata; HLG is the broadcast standard. Our API outputs HDR10 first — the most compatible choice — with HDR10+ and HLG on request.
- HDR10 — static metadata, everything plays it
- HDR10+/Dolby Vision — dynamic metadata, narrower ecosystem
- HLG — broadcast delivery
- Our API: HDR10 default, HDR10+/HLG on request
FAQ
Common questions
Is HDR really better than SDR?
On a capable display, yes — more brightness range, wider colors and smoother gradients. On SDR screens the HDR master simply tone-maps back down.
Can every SDR video be converted to HDR?
Most can, but results depend on source quality. Severely compressed or very dark footage gains less. The model was trained on professionally graded SDR-to-HDR pairs.
What is the difference between HDR10, HDR10+, Dolby Vision and HLG?
HDR10 uses static metadata; HDR10+ and Dolby Vision add per-scene dynamic metadata; HLG is the broadcast standard. Our API outputs HDR10 by default with HDR10+/HLG on request.
How much does it cost to convert SDR to HDR?
The SDR2HDR API bills per second of input video with a free tier for evaluation — see the pricing page.