Convert HEIF/AVIF file to JPEG with gain map

[xeoneux]

Hi, I'm new at Rust so I do not understand most of the code in this repo. I'm trying to convert my camera's images (it shoots in HEIF with HDR metadata) to a JPEG with gain map (so that it's visible on iPhone as an HDR JPEG image).

Would that be achievable with your library?

Thanks!

[awxkee]

Hi.

No, the library focus on processing and there are no plans to implement encoder/decoder here.

The thing you intent to do is barely achievable. libheif support of gainmaps still is not landed. Thus, you have to load Apple gainmap which have different format from HEIF by using Apple's API only on mac, because there is literally no alternatives to libheif and there is no gainmap support. Then, you'll have to figure out how to convert Apple gainmap to ISO standard, because Apple gainmap is not the same to submitted Adobe ISO standard. Then, you could save the image by libultrahdr. I'm not sure that there is support of external source gainmaps writing, but source code is available so you could patch it.

So, to do what you want, you likely have to patch two C libraries ( one if you have Mac and their API allows you to extract gain map ), investigate two experimental standards and figure out how to convert one into the other.

Hope, that helps!