Are there any playback constraints based on fairplay client type (OS X, iOS, etc) related to video frame rate and resolution?
I have noticed that, for example, 768x432 main 3.2@60fps video produces MEDIA_ERR_DECODE on OS X in Safari but fine on iOS. But, for example, 1024x576 high 3.2@60fps plays fine both on OS X in Safari and on iOS. KSM is valid and well tested. Furthermore, trying to figure out what is going on I created specific stream with 768x432 main 3.2@60fps and 1024x576 high 3.2@60fps renditions using same encryption key then used CKC of not playable 768x432 for playable 1024x576 which retained successfull playback using CKC of other not playbale rendition. That proves KSM is fine.