Re: Quicktime MIDI
Re: Quicktime MIDI
- Subject: Re: Quicktime MIDI
- From: Jim Nevin <email@hidden>
- Date: Wed, 19 Jan 2005 16:33:37 -0500
What is needed is a some type of bridging software that enables a Quicktime Music track to be seen as a CoreAudio endpoint (I believe). Presumably, this could be a Quicktime component -- perhaps a derived media handler or one that captures the QT music media handler entirely -- that presents itself as a virtual endpoint to CoreAudio, thereby allowing QT MIDI output to be routed to CoreAudio devices.
This type of functionality would be extremely valuable, enabling Quicktime, with its excellent synchronization of MIDI to other media, to act as a signal source to other MIDI devices under OS X. One example of this usage would be to enable Quicktime music tracks to direct MIDI-controllable devices such as lighting systems and effects processors in concert with a Quicktime movie, e.g. in a Quicktime VJ application such as Module8.
I am currently trying to develop such a QT component, but would welcome anyone's advice or sample code.
David Cake's response to William Stewart is spot on. We are not objecting to CoreAudio. We want to use Quicktime in conjunction with CoreAudio.
My understanding is that there may be some APIs for this purpose in the upcoming Quicktime 7. Can anyone shed further light on this?
Thanks!
At 4:20 PM -0800 8/11/04, William Stewart wrote:
The CoreAudio API's provide several alternatives for applications to provide
this behaviour for users and for quite some time now (years, not months)
we've been very clear about the need for developers to move over to CA APIs
from both SoundMgr and QT Music APIs.
Just to reopen this slightly issue after a couple of weeks - sorry, I've been travelling and not paying enough attention to the CA list.
CoreAudio does NOT provide a useful alternative as far as I know. What is wanted it to have a way to play MIDI from a QuickTime file in synch with the other contents of the file, using something other than the default DLS Synth. If there is an alternative, please explain.
The exhortation to developers is backwards. Providing access to external synths from QuickTime isn't an issue of people wanting to use old APIs where they should be using the new, its an issue of people wanting to use the new OS functionality for all MIDI purposes and not being able too because the appropriate compatibility work hasn't been done. Not that Apple necessarily has to do that work, limited resources and so on - but Apple certainly shouldn't tell people not to do it. The requested functionality exactly IS a case of people wanting to move from QT Music APIs, and a part of the system necessary to do so not being there.
Or to put it another way, this answer seems to be saying that the issue is how should we play MIDI, and the answer is we should use CoreMIDI. Which is true. But that's not the issue. The issue is how should we play several different media synchronised from a single source, one of which happens to be MIDI - and despite the wonders of the CA APIs for pure audio/MIDI, the answer to that question is still emphatically QuickTime, just part of the support to do so flexibly is missing.
The issues isn't that people want to use QuickTime music APIs where they should be using CoreMIDI at all, the issue is that there is a source of MIDI signals within the OS that can't be routed to CoreMIDI as it should be.
Doug Wyatt wrote
You mean the Music tab of the QuickTime pref panel? It's used for selecting the default DLS/Sound Font sample bank.
Thats all you can do with it right now, but that doesn't mean that is all you are supposed to be able to do with it. Routing to external MIDI was definitely possible from there in OS 9, and as has been pointed out its supposed to be possible according to the OS X documentation.
If I had more experience with component development and/or some code showing how to do it in OS 9 I'd just try and right the code myself. But instead I'm going to complain - because while I don't expect Apple to prioritise every bit of missing functionality I happen to want, I greatly object to Apple spuriously telling developers it shouldn't be done at all when it clearly should.
Cheers
David
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