ICC profile retention limits HEIC cleanup in mat2
HEIC support in mat2 stays narrow because embedded ICC profiles cannot be removed. That leaves cleaning restricted to lightweight mode, which is a fairly blunt limit for a tool that otherwise strips metadata with little ceremony. If a file needs a full scrub, HEIC is the awkward one in the stack.
Why HEIC stops at lightweight mode
HEIC files can still be processed, but only inside lightweight mode. The limit sits in the embedded ICC profile: if the profile cannot be removed, the file cannot be treated as fully clean in the same way as other formats.
That matters because colour profile data is not the sort of thing you can hand-wave away. If the profile stays in place, the file still carries embedded metadata the cleaner cannot touch. The result is a partial pass, not the kind of wipe people usually expect from HEIC metadata stripping.
Embedded ICC profiles are the blocker
The ICC profile is the hard stop here. mat2 can strip other metadata, but the profile remains embedded in the HEIC file, so the cleaner has to back off before it reaches the point of full removal.
That is a practical limit, not a cosmetic one. A file may look cleaned, but the remaining profile means the job is incomplete by design.
What mat2 still strips from the file
Even with that limit, mat2 still removes other metadata it can reach. The file is not left untouched, just constrained by what the format allows the tool to handle safely.
That makes lightweight mode a narrower pass rather than a no-op. It still does useful work, but it stops where the ICC profile stops it.
What that means in practice for metadata stripping
HEIC is the format that forces a more cautious approach. If the aim is to remove everything that can reasonably be removed, the tool can only go so far before the embedded profile gets in the way.
That creates a simple rule for use in the real world: HEIC files are fine for limited cleanup, but not for the sort of total metadata stripping people may expect from simpler formats. The tool can clean them, just not completely.
Where ExifTool still does the heavy lifting
For more demanding metadata work, ExifTool remains the heavy lifter. mat2 is useful when the job is straightforward, but HEIC shows the point where a lighter cleaner runs out of road.
That is the practical split. mat2 handles the easy, repeatable stripping. ExifTool is still the one to reach for when the file format needs deeper handling.
AVIF and JPEG XL sit in a different lane
mat2 0.15.0 also adds AVIF and JPEG XL support, and those formats sit apart from the HEIC limitation. Their presence signals broader modern image support, but it does not change the ICC profile problem in HEIC.
So the picture is uneven: AVIF and JPEG XL are in, HEIC is partly in, and lightweight mode is the boundary line. That is a normal sort of compromise for a metadata cleaner, even if it is mildly annoying when the file in front of you is HEIC.
