openal

I am doing an application that involves playing back a song in a multi track format (drums, vocals, guitar, piano, etc...). I don't need to do any fancy audio processing to each track, all I need to be able to do is play, pause, and mute/unmute each track. I had been using multiple instances of AVAudioPlayer but when performing device testing, I noticed that the tracks are playing very slightly out of sync when they are first played. Furthermore, when I pause and play the tracks they continue to get more out of sync. After a bit of research I've realized that AVAudioplayer just has too much

iOS has various audio frameworks from the higher-level that lets you simply play a specified file, to the lower level that lets you get at the raw PCM data, and everything in between. For our app, we just need to play external files (WAV, AIFF, MP3) but we need to do so in response to pressing a button and we need that latency to be as small as possible. (It's for queueing in live productions.) Now the AVAudioPlayer and such work to play simple file assets (via their URL), but its latency in actually starting the sound is too great. With larger files of more than five minutes in length, the

Pitch means "perceived frequency". Nice. But when I make pitch very low in OpenAL, sound plays a lot of times longer. If I make it very high, sound plays very short but with high frequency. For me, logically the consequence of making slower or faster. Or is pitch != speed? Paul R has a pretty good answer, but I'd like to expand on it a bit. If you think of the sound as a series of pulses (and it kind of is), then a higher pitch will have more pulses per second (higher frequency) and a lower pitch will have fewer (lower frequency). To lower the pitch of an existing sound, you have to spread

I am trying to do sound capture on iOS using OpenAL (I am writing a cross-platform library, that's why I avoid iOS-specific ways to record sound). Out of the box OpenAL capture does not work, but there exists a known workaround: open an output context before starting capture . This solution worked for me on iOS 5.0. However on iOS 5.1.1, the workaround only helps for the first sample I try to record. (I switch my AudioSession to PlayAndRecord before starting capture and open the default output device. After recording my sample, I close the device and switch the session back to whatever it was.