Is the AudioFilePlayer audio unit compatible with sandboxing?
Is the AudioFilePlayer audio unit compatible with sandboxing?
- Subject: Is the AudioFilePlayer audio unit compatible with sandboxing?
- From: Andrew Madsen <email@hidden>
- Date: Thu, 21 Feb 2013 16:40:57 -0700
I've run into a problem using the AudioFilePlayer audio unit with app sandboxing enabled on OS X 10.8. I have an AUGraph with only two nodes, consisting of an AudioFilePlayer unit connected to a DefaultOutput unit. The goal (right now) is to simply play a single audio file. If sandboxing is not enabled, everything works fine. If I enable sandboxing, AUGraphOpen() returns error -3000 (invalidComponentID). If I remove the file player node from the AUGraph, the error goes away, which at least suggests that the audio file player is causing the problem.
Here's the code I use to set the file player node up:
OSStatus AddFileToGraph(AUGraph graph, NSURL *fileURL, AudioFileInfo *outFileInfo, AUNode *outFilePlayerNode)
{
OSStatus error = noErr;
if ((error = AudioFileOpenURL((__bridge CFURLRef)fileURL, kAudioFileReadPermission, 0, &outFileInfo->inputFile))) {
NSLog(@"Could not open audio file at %@ (%ld)", fileURL, (long)error);
return error;
}
// Get the audio data format from the file
UInt32 propSize = sizeof(outFileInfo->inputFormat);
if ((error = AudioFileGetProperty(outFileInfo->inputFile, kAudioFilePropertyDataFormat, &propSize, &outFileInfo->inputFormat))) {
NSLog(@"Couldn't get format of input file %@", fileURL);
return error;
}
// Add AUAudioFilePlayer node
AudioComponentDescription fileplayercd = {0};
fileplayercd.componentType = kAudioUnitType_Generator;
fileplayercd.componentSubType = kAudioUnitSubType_AudioFilePlayer;
fileplayercd.componentManufacturer = kAudioUnitManufacturer_Apple;
fileplayercd.componentFlags = kAudioComponentFlag_SandboxSafe;
if ((error = AUGraphAddNode(graph, &fileplayercd, outFilePlayerNode))) {
NSLog(@"AUAudioFilePlayer node not found (%ld)", (long)error);
return error;
}
return error;
}
Note that fileURL in the AudioFileOpenURL() call is a URL obtained from security scoped bookmark data, and is the URL to a file that has been dragged into the application by the user.
If I set the com.apple.security.temporary-exception.audio-unit-host sandboxing entitlement, when AUGraphOpen() is called, the user is prompted to lower security settings, and assuming they accept, playback again works fine (the sandbox is disabled).
So, this points to the AudioFilePlayer unit not being sandbox-safe/compatible. Is this true? It would surprise me that Apple didn't fix such an important part of the CoreAudio API to be sandbox compatible. Note that I specify the kAudioComponentFlag_SandboxSafe flag in the description passed to AUGraphAddNode, and that call does not fail.
I can only find one reference to AudioFilePlayer not being sandbox-safe online, in the form of this post to list: http://lists.apple.com/archives/coreaudio-api/2012/Jul/msg00064.html . It didn't receive any replies. Perhaps I'm making some other subtle mistake (I'm new to Core Audio) that happens to cause a problem with sandboxing enabled, but not when it's disabled?
Thanks,
Andrew Madsen
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