alpha image can not be decoded correctly on IOS and Mac

[Eastsea-in-east]

How to reproduce:

• the input image here saved to alpha.png
• ./heif-enc alpha.png -o alpha_1_10.heic
• ./heif-enc alpha.png -o alpha_1_9.heic

Issue: Within v1.10.0 release, the generated heic image "alpha_1_10.heic"

• In IOS: can not be loaded
• In MAC: can not be loaded

Within v1.9.1 release, the generated heic image "alpha_1_9.heic"

• In IOS: can be loaded, but alpha effect doens't work totally(airdrop the .png and .heic file to iphone, save them in "file" application. And there are different appearance in the background for them).
• In MAC: can be loaded, alpha effect work well.

[farindk]

Could you please check whether this is actually the same issue as #405 and has hence been fixed with the changes in the current master branch?

[Eastsea-in-east]

Dirk,

Yes, with the current master the issue is fixed partly:

1. The output .heic image can be loaded on mac correctly with alpha effect
2. The output .heic image can be loaded on iphone but with opaque effect( no alpha effect, it is wrong)

could you confirm the issue? Thanks.

BTW, how to confirm the alpha effect: airdrop the .png and .heic file to iphone, and save them in iphone "file" application. And there are different appearance in the background for them.

-Eastsea