So I finally sorted this out! Ugh, what an information scavenger hunt. Anyway, here is the bit in the docs for ExtAudioFile that I missed (see bolded text). I wasn’t setting this property. Data was being written to my .m4a file but it was unreadable at playback. So to sum up: I have a bunch … Read more
To determine if a device is an input device you need to check and see if it has any input channels. Here is code modified from the Objective-C class here: static BOOL DeviceHasBuffersInScope(AudioObjectID deviceID, AudioObjectPropertyScope scope) { NSCParameterAssert(deviceID != kAudioObjectUnknown); AudioObjectPropertyAddress propertyAddress = { .mSelector = kAudioDevicePropertyStreamConfiguration, .mScope = scope, .mElement = kAudioObjectPropertyElementWildcard }; UInt32 … Read more
I was searching for a similar thing and decided to “roll my own.” I realize this is an old post, but in case anyone else is in search of this, here is my solution. it is relatively quick and dirty and normalizes the image to “full scale”. the images it creates are “wide” ie you … Read more
you can use dirac-2 from dsp dimension for pitch shifting on the iphone. quote: – “DIRAC2 is available as both a commercial object library offering unlimited sample rates and phase locked multichannel support and as a free single channel, 44.1/48kHz LE version.”
The Flite speech synthesis engine can be run on an iPhone, ref http://artofsystems.blogspot.com/2009/02/speech-synthesis-on-iphone-with-flite.html