Re: M4P through AUHAL to multichannel device (last call)
Re: M4P through AUHAL to multichannel device (last call)
- Subject: Re: M4P through AUHAL to multichannel device (last call)
- From: Doug Wyatt <email@hidden>
- Date: Fri, 23 Jan 2004 17:06:48 -0800
If it's protected content, then you have to use QuickTime or iTunes to
play the file. But both QuickTime (via SoundManager) and iTunes (via
CoreAudio) respect the default stereo pair you have selected for your
multichannel device -- in Audio MIDI Setup or HALLab.
In fact you can even programmatically change the default stereo pair
using AudioDeviceSetProperty. Or are you wanting to play multiple
protected files through multiple stereo pairs, all at once?
If it's an unprotected .m4a and you want to bypass the Sound Manager,
then you can -- as I am learning how to do today -- open the MP4 file
as a QuickTime movie, find the audio track, find the media, step
through the "interesting times" in the media, which will yield a series
of AAC packets which can be passed through the AudioConverter to decode
them.
There is a little gotcha involving configuring the decoder, but if you
get that far before I do, please ask again.
Doug
On Jan 22, 2004, at 18:25, Austin Shoemaker wrote:
All I want to do is play my music to any stereo pair on my
multichannel output hardware.
The only problem is protected AAC, which is not friends with CoreAudio.
The only workarounds I have found to be effective are convoluted and
inefficient, and hence not acceptable.
I guess the dust has not settled around the technology line between QT
and CA, and that this niche of functionality (M4P on multichannel
hardware) has been caught in the fringe.
Before I rewrite everything to use QT through sdev components, I would
really appreciate any official comment on this. Especially if the
answer is "I don't know" or "That's right, CoreAudio will not work",
because I really need to know, and I would prefer to choose CoreAudio
as my long-term solution.
Thanks to everyone who has contributed to this inquiry so far.
Sincerely,
Austin
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