MusicSequence, DLS and QuickTime music
MusicSequence, DLS and QuickTime music
- Subject: MusicSequence, DLS and QuickTime music
- From: Christopher Corbell <email@hidden>
- Date: Fri, 3 Oct 2003 12:10:52 -0700
I'm hoping to get some help doing something that seems
like it should be very easy with CA and QuickTime.
My app exports SMF files from AudioToolbox
MusicSequence objects. It also uses QuickTime
to convert these to QuickTime (music) movies
if the user chooses.
I've been wrestling for over a week with the issue
of supporting custom SF2 or DLS instruments. The
support's great in the AudioToolbox - the sequence
plays back with custom instrument tracks perfectly,
but the DLS information is lost in SMF. I'd like
to post-process the converted .MOV file to "fix up"
the channels that were using custom banks.
I've tried using the old QTMA sample code to determine
how to set an atomic instrument and been frustrated.
It's all been guesswork because there is no clear
documentation on exactly what sequences of calls
are needed to set up a DLS instrument for a specific
MIDI channel in a Track, nor is there a clear spec
on the binary structure of the QuickTime music file.
All of the AtomicInstrument etc. documentation
is oriented toward live playing with a NoteAllocator,
but when I try to massage this into re-building
the MusicSampleDescription it fails in any of a
variety of ways, either when setting the Media
sample header, when trying to update the Movie
file, or when playing it afterward. I have gotten
close (the custom instrument's name shows up in
the Instruments list in QuickTime Pro, but doesn't
play).
I would have given up long ago, but for the ease with
which QuickTime Pro seems to accomplish the same task.
Just open the converted SMF movie, show music track
info, double-click an instrument and change it to the
custom sound bank. I've spent days doing this, followed
by binary compares of QTPro's exported files against
mine, and still haven't discovered the trick.
Is this a lost cause? Or can anyone suggest a
better approach?
Thanks,
Christopher
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