change sound pitch (not in realtime)

问题

i alway had this question in my mind, but wherever i asked, i could never get an answer or a suggestion that would be helpful:

How can i pitch a sound (not realtime) ?

Im using AVFoundation framework to play my sounds like so:

AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:TempRecFile error:nil];
    player.volume = 1;
    [player play];

How can i set the pitch or the frequency of my sound without having to use some othere frameworks like OpenAL. Although, if you know a place where i could learn some OpenAl you're very welcome :D

回答1:

There are a few iPhone time-pitch shifting libraries mentioned the this StackOverflow answer: Real-time Pitch Shifting on the iPhone, which work offline as well as potentially in real-time.

Here's a wikipedia article on time-pitch technology, and a dspdimention overview on the topic.

来源：https://stackoverflow.com/questions/5851855/change-sound-pitch-not-in-realtime