Re: Need a callback on the MusicPlayer
Re: Need a callback on the MusicPlayer
- Subject: Re: Need a callback on the MusicPlayer
- From: Bill Stewart <email@hidden>
- Date: Thu, 6 Mar 2003 12:45:07 -0800
Philippe
OK - I'm stupid - I finally understood what you're asking...
We won't provide a TrackSetDestCallback API in the near future...
However, I think Chris' suggestion is worth pursuing. In the SDK
there's code in the 3DMixer test program that registers a private
component - the UI for either the reverb or the 3DMixer...
I'd suggest your best approach here is to write a custom
"TrackMusicDevice" that can feed its samples into the audio stream that
is part of your processing graph that the sequence is controlling. I
think that would work quite well as the synchronisation would be taken
care of for you by the sequence and its association with the tracks in
your app and the audio data that is generated by the graph.
Bill
On Thursday, March 6, 2003, at 11:21 AM, Chris Rogers wrote:
Philippe,
Also, it is possible to create a private AudioUnit/MusicDevice which
would not
be visible to the rest of the system. You would put this AudioUnit,
for example, in your application bundle and then register it manually
with the component manager...
Chris Rogers
Core Audio
Apple Computer
Its coming...
There will be a way to instantiate a UserData callback on a given
sequence... If there, the scheduler will call your callback with
every user data event it finds - both in chasing and in playback -
giving you the sequence, track, start and end beats for what it is
rendering (these are tweaked in a different way so that you know when
you're chasing v playing), event time of the user event and of course
the user event itself.
Whilst chasing if you don't want these callbacks, you can just mute
the tracks that have these events in them
Bill
On Wednesday, March 5, 2003, at 11:06 PM, Philippe Wicker wrote:
Hi all,
This is a question/suggestion to the CoreAudio/CoreMIDI team.
When playing a sequence with the MusicPlayer, it is today possible
to direct MIDI events - on a per track basis - either to an AU or to
a MIDIEndpoint. These 2 methods involves "items" which are "public",
I mean accessible by any CoreAudio compliant application. There are
situations where you may not want your MIDI destination to be
public. To give a real case: I'd like to use the MusicPlayer to
control the playback of audio tracks. I could implement this as a
MusicDevice. I don't like this solution because 1) the AU is
"public", 2) I just need a very limited subset of the AU features to
playback my audio track. I could redirect the MIDI events to a
MIDIEndpoint and do my own job in the MIDIReadProc. I don't like it
too, because the endpoint is public and may receive events from any
sources in the system.
A good solution, in my opinion, would be to add a third MIDI events
destination for a MusicPlayer track. We could pass a callback that
would be called by the MusicPlayer when MIDI events are to be played
from a track. The API could be something like
MusicTrackSetDestCallback(track, callback). This would be a very
flexible solution.
What's your feeling about this?
Philippe Wicker
email@hidden
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