My app uses the low level Extended Audio File Services and exhibits this same iOS 17 issue when I call the ExtAudioFileRead function to get the first sample from the m4a file url of an iTunes purchased or uploaded song file. The error code returned is 1 and the device log has this line "ExtAudioFile.cpp:1,187 about to throw 1: convert audio packets (pcm read)" All other extaudioxxxx calls seems to work normally, but the inability to read the samples from the aac audio format converted to pcm prevents playback.

1

I did eventually find the solution to this issue. Turns out the users were picking songs from playlists but the individual songs had not been added to their library. Using a playlist query instead of a songs query would find the item by persistent ID. Now, of course, with iOS 14 those items selected with the picker from playlists that do not exist in the library have a '0' value persistent Id. Another iOS update, another SMH moment. In theory, I could add the items with the '0' persistentID to the MPMediaLibrary with the playbackStoreID, but that function is broken and hangs in every iOS 14.x.x version up to 14.4.1 so far. Sigh...