The duration of an audio file

Question

I need to determine the length of my audio file. Right now I am using .caf files, but I can see how I might this to work with mp3s also.
Anyhow, I see this tidbit from the Apple Core Audio Spec:
mSampleRate
The number of sample frames per second of the data. You can combine this value with the frames per packet to determine the amount of time represented by a packet. This value must be nonzero.
That's looking good, except this will only tell me the duration of the packet. I can't find out how many packets my total audio file has. (And yes, this is a file, not a stream.)
What am I missing? Any help is appreciated.
Thank you.

Answer 1

Unless I am mis-interpreting the question this should work:
+(NSTimeInterval)getDurationForAudioFile:(NSString*)path
OSStatus status = 0;
AudioFileID audioFile;
NSTimeInterval seconds;
UInt32 propertySize;
propertySize = sizeof(seconds);
status = AudioFileOpenURL((CFURLRef)[NSURL fileURLWithPath:path],
fsRdPerm, AUDIOFILETYPE, &audioFile);
status = AudioFileGetProperty (
audioFile,
kAudioFilePropertyEstimatedDuration,
&propertySize,
&seconds);
return seconds;
Message was edited by: Amber Star