MundoKit

PNG color and HDR metadata inspector

Open one PNG to inspect its chunks and color metadata. The file stays in your browser and is never modified; download the inspection report if needed.

Select one PNG for local metadata inspection. JavaScript is required.

How it works

The inspector bounds each chunk, checks its CRC and decodes supported metadata. PNG Third Edition defines cICP signaling, mDCV mastering metadata and cLLI light levels. Luminance integers are divided by 10,000; mDCV chromaticities by 50,000. Four-byte metadata integers above 2,147,483,647 are errors and are not decoded; CRCs use all 32 bits. No intermediate rounding is applied.

Application limits: one file, 30 MB and 10,000 chunks. Pixels and compressed profiles are not decoded. This is a metadata report, not complete PNG conformance validation.

Worked examples

PQ signal

cICP bytes 09 10 00 01 signal PQ with full range. The report shows transfer code 16.

Content light levels

Stored cLLI integers 10,000,000 and 2,500,000 decode to 1,000 and 250 cd/m². Zero means unknown.

Frequently asked questions

Does this prove the image is displayed in HDR?
No. Metadata signaling alone cannot establish pixel correctness or display behavior.
Why is mDCV without cICP flagged?
The pinned edition requires cICP to accompany mDCV.
Can color chunks coexist?
Yes. Understood cICP takes precedence. sRGB and iCCP together are discouraged.
What is not inspected?
Pixel decompression, ICC profile contents, APNG frame semantics and complete chunk-specific conformance are outside scope.
Are my files uploaded?
No. The browser reads one selected local file and produces an optional JSON report.

Sources

Last reviewed 2026-11-14; next review due by 2027-11-14. The method is written out above so you can check our math.