Re: Newbie file format question
Re: Newbie file format question
- Subject: Re: Newbie file format question
- From: john <email@hidden>
- Date: Fri, 16 Jan 2004 17:57:16 -0500
Hi Adam,
That's not a dumb question at all, the answer is not even slightly
intuitively available.
The kAudioFormatMPEGAAC I believe refers to the AudioConverter type for
AAC encoding. I'm guessing the kAudioFileAAC_ADTSType refers to what
you'd use if you were writing/reading an file using AudioFile.
Perhaps the iTunes format is not the same thing as standard AAC? Try
encoding a file in mp4 with Quicktime and see if you can get info on
it. That might answer your first question. I don't know about your
second one.
I'm hoping someone else will respond with better information.
-- John
Hi everybody,
I looked thru the archives and documentation, but I'm still having
trouble understanding which/how audio formats are supported. My main
confusion is with AAC audio.
In the Audio Format docs, I see kAudioFormatMPEG4AAC. So I assume Core
Audio can understand and manipulate this format. However, the Audio
File API mentions its supported types, and mpeg4 aac files don't
appear. There's the aac_adts format. I assume that's different from mp4
aac, for if I open an iTunes-style m4a file with AudioFileOpen(), I get
an 'unsupported file-type' return status.
So I guess my question is how would you get mpeg4aac-formatted data
into Core Audio if the AudioToolbox doesn't open mp4/aac files? Also,
what is the difference between aac_adts format and AAC formatted mp4
files?
Sorry for the dumb questions, I'm a lil overwhelmed I guess,
Thanks,
Adam Ohren
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