What _C4 mode means ?

[vladimir12345]

There are _AC4 and _C4 mode methods, for example:
ippiAdd_8u_AC4R_Sfs(...) and ippiAdd_8u_C4R_Sfs(...)
Spec explains that _AC4 means 3color channels + 1 alpha channel, alpha channel is ignored by most of methods.
I didn't find any explanation what_C4 means ? 3 color channels + 1 alpha channel but the alpha channel is processed as a regular color channel ?

[Vladimir_Dudnik]

Hi,

IPP functions with C4 mode will process all 4 channels without assumption that there might be an alpha channel.

Regards,
Vladimir