Re: iTunes back door, API, DLL raw sample question
Re: iTunes back door, API, DLL raw sample question
- Subject: Re: iTunes back door, API, DLL raw sample question
- From: Brian Willoughby <email@hidden>
- Date: Fri, 29 May 2009 13:50:42 -0700
If you want to play 16/44.1 tracks back-to-back with 24/96, then you
have an interesting problem to solve. No amount of hacking iTunes is
going to get you the results you probably want.
I suggest that you write your own player. There is support in
CoreAudio to notify your application when Audio MIDI Setup changes,
and there is support in CoreAudio for reading (and playing) nearly
all audio file formats except those purchased in iTunes (which won't
play in a Pro Audio DAW anyway). Your application can force the
volume control to 100% and avoid any EQ or other sound altering
options. For your purist approach, I doubt that you want crossfades
or any of the other fancy iTunes features, so all you really need to
implement is a playlist. You may find AudioQueue to be too high
level to meet your needs, but that still leaves a great deal of
CoreAudio features that you can still take advantage of to make your
job very easy.
You could also consider starting with one of the open source audio
programs like Play.app and then tweak only if necessary.
Going through the back door of iTunes, if that is even possible, will
end up being more work, and you're still stuck with an audio engine
that is not designed to directly meet your needs. Any new release of
iTunes could add a new EQ or sound altering option that your back
door does not defeat, and you're back to ground zero. I believe that
the list of iTunes features that you need to re-implement in your own
application is much, much shorter than the list of problems in iTunes
that you would have to work around, and the latter list is growing.
Remember that you have support in CoreAudio for most of the features
in iTunes, so you're not really going to have to write much code at all.
Brian Willoughby
Sound Consulting
On May 29, 2009, at 13:34, Gordon Rankin wrote:
I design high end audio asynchronous usb dac hardware. A lot of
customers have found that iTunes while nice may not sound as good as
actually playing tracks in pro audio tools. The problem with Pro
Audio is one track at a time.
One of the reason's why iTunes does not sound as good is that iTunes
takes a snap shot of Audio Midi Setup for the device output in
question and resamples to that rate and bit size before it goes out.
So you may have a 44.1/16 bit track then a 24/96 track and they will
both be resampled to the rate specified in the Audio Midi setup.
Other problems happen when users forget setting the volume control to
100% and using eq and other sound altering options.
The nice thing about iTunes is there are a bunch of applications for
remote access and control as well as the ripping and burning
capabilities.
So I had an idea that maybe there was an interface for iTunes were
the sample and sample rate info was passed to a DLL or API for
processing that we could hijack the sample and out put it to a known
device as is without any processing and change the sample rate on the
fly. In return to iTunes we would pass the altered sample back as a
ZERO so when iTunes passed the sample onto the mixer that it would
not interfere or be output as anything.
Anything like that? Anyone interested in helping me out with this?
Thanks
Gordon
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