Re: Preserve pitch
Re: Preserve pitch
- Subject: Re: Preserve pitch
- From: Greg Chapman <email@hidden>
- Date: Wed, 1 Jun 2005 13:09:23 -0700
Chris is right that QT always uses the low-quality mode of AUPitch.
If you want to hear what it sounds like at half speed, open your
audio file in QTPlayer, hit <cmd-K> (A/V controls), and use the
Playback Speed control to change the speed to 0.5.
Once you have the audio file (AIFF?) you should just do
NewMovieFrom...() on it, and now you have a movie (in RAM) whose
media data is in an AIFF file. You can then save this as a self-
contained movie on disk if you like.
There are more complicated things you can do to write directly to a
movie (MovieExportFromProceduresToDataRef), but if you're in a hurry,
it's easier to write to an AIFF file (with AudioFile APIs) and then
open it as a movie. Even if it is 5.1.
Greg
On Jun 1, 2005, at 12:59 PM, Jan E. Schotsman wrote:
On 1-jun-05, at 21:04, Chris Rogers wrote:
Although it is possible to do this directly in QuickTime, currently
this is only using the low-quality time-stretching algorithm.
Using the AUTimePitch unit directly will allow use of the high-
quality algorithm as well. This may or may not be important
in your particular application, so using QuickTime directly may be a
simpler and more direct solution to your problem....
I think I want both. I want the quick solution because I am
finalizing the next version of my application, and I want the high
quality version because I am always in favor of high quality ;-)
and I think if you play music at half speed you probably need it.
Can you explain how I need to go about writing the converted data
to a file? Can I install an output callback or how does this work?
I understand how PlayAudioFileLite works and I have looked at the
AudioFile API, which looks pretty simple, but the problem is how
to connect to the other side of the unit.
Once I have the audio file, can I just copy it to a movie with
standard QT calls (even if it is 5.1 or whatever)?
Jan.
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