Check whether a HEIC photo contains HDR gain map data
See whether a HEIC photo carries HDR information: an Apple gain map, an ISO gain map item, PQ or HLG transfer, and clli or mdcv boxes. You can preview the gain map itself.
Drop HEIC photos here, or pick them from your device
Stays on your device. Nothing is uploaded.
Processing on this device
How to use it
- Drop a HEIC photo onto the page.
- Read which HDR indicators were found.
- Preview the gain map if one exists.
- Use the findings to decide how to convert the photo.
What it keeps
- The file, which is only read.
What it removes or changes
- Nothing changes. This is a report.
Limits
- The tool does not render HDR tone mapping. Previews it shows are standard range (SDR).
- Finding a gain map tells you the data exists, not how a given display will use it.
- Conversions to JPG, PNG or WebP produce standard-range images.
Compatibility
HDR display depends on your screen, operating system and app. Apple devices apply the gain map. Many other programs ignore it and show the base image. If a converted photo looks flatter than on your phone, HDR may be the reason.
Privacy
The inspection runs in your browser. The photo is not uploaded.
Gain map versus true HDR formats
A gain map stores an ordinary base image plus extra data telling a capable display how much brighter to make each region. PQ and HLG describe brightness directly in the signal. The inspector reports which of these a file uses, so you know how much of the HDR look a plain conversion will leave behind.
Troubleshooting
No gain map was found.
Not every photo has one. It depends on camera mode and settings.
Converted JPGs look flatter than the original.
The HDR boost is not carried into the standard-range output. The base image remains.
The gain map preview looks strange.
It is a map of brightness changes, not a picture.
Frequently asked questions
Can this convert HDR photos?
No. Previews and conversions are standard range.
Does it detect ISO gain maps?
Yes, tmap items, as well as Apple's.
Why does HDR matter for conversion?
Because standard formats lose the brightness boost.