This is similar to The Pitch Shift question, except I want to keep my audio at the same pitch, but play it slower or faster -- time shift it. (On the iPhone.)
Can anyone point me to a library, tutorial or other reading to help with that?
Thanks!
A:
Isn't this essentially the same thing? For example, if you pitch-shift something up an octave, then play it back at half speed, then it will play at the original pitch, but last twice as long...
psmears
2010-06-30 18:19:47
Right. The question is: how to play it back at half speed. "Just modify the sound samples" isn't a detailed enough answer for me to follow what needs to be done.
Olie
2010-07-02 14:21:47
@Olie - I didn't say "Just modify the sound samples" :-) How to change the playback rate depends on what API you're using to play the audio, but if you're using one that uses the `AudioStreamBasicDescription` structure, you may be able to modify the `mSampleRate` element to adjust the playback rate. Have you tried out any of the solutions from the "Pitch Shift" question yet? Which API did you use to play the sounds?
psmears
2010-07-02 14:47:47
@psmears: Ah, yes -- sorry, I didn't mean to imply that you said that, only that it's a common theme in other answers I've seen, and I'm not quite up to the level of being able to interpret that sort of glossing-over.I'm not currently tied to any particular playback mechanism, as tempo-shifting is a necessary component. I'll investigate the AudioStream stuff.To the answer you gave: "If you pitch shift something up an octave" -- how? "...then play it back at half speed" -- how? That's what I was getting at.Thanks!
Olie
2010-07-02 23:17:17