core-audio

I was trying to set up an audio unit to render the music (instead of Audio Queue.. which was too opaque for my purposes).. iOS doesn't have this property kAudioDevicePropertyBufferFrameSize .. any idea how I can derive this value to set up the buffer size of my IO unit? I found this post interesting.. it asks about the possibility of using a combination of kAudioSessionProperty_CurrentHardwareIOBufferDuration and kAudioSessionProperty_CurrentHardwareOutputLatency audio session properties to determine that value.. but there is no answer.. any ideas? You can use the kAudioSessionProperty

I have a project for Android reading a short[] array with PCM data from microphone Buffer for live analysis. I need to convert this functionality to iOS Swift. In Android it is very simple and looks like this.. import android.media.AudioFormat; import android.media.AudioRecord; ... AudioRecord recorder = new AudioRecord(MediaRecorder.AudioSource.DEFAULT, someSampleRate, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, AudioRecord.getMinBufferSize(...)); recorder.startRecording(); later I read the buffer with recorder.read(data, offset, length); //data is short[] (That's what i'm

I have the following code for generating an audio tone of given frequency and duration. It's loosely based on this answer for doing the same thing on Android (thanks: @Steve Pomeroy): https://stackoverflow.com/a/3731075/973364 import Foundation import CoreAudio import AVFoundation import Darwin class AudioUtil { class func play(frequency: Int, durationMs: Int) -> Void { let sampleRateHz: Double = 8000.0 let numberOfSamples = Int((Double(durationMs) / 1000 * sampleRateHz)) let factor: Double = 2 * M_PI / (sampleRateHz/Double(frequency)) // Generate an array of Doubles. var samples = [Double]

I'm building an app that has to track input amplitude of users mic. AudioKit has a bunch of handy objects for my needs: AKAmplitudeTracker and so. I haven't found any viable info on how is it supposed to start AudioKit, begin tracking etc. For now all code related to AudioKit initialization is in viewDidLoad method of my root VC of audio recorder module. It is not correct, because random errors occur and I can't track whats wrong. Code below shows how I use AudioKit now. var silence: AKBooster! var tracker: AKAmplitudeTracker! var mic: AKMicrophone! ... override func viewDidLoad() { super

I expect I need to do a bitwise comparison but I am unclear on how that is done in Objective-C syntax. The enum definition of MPMediaType is below. What I need to do is ensure the MPMediaItem is not video at all because AVAssetReader is choking on video files despite filtering to MPMediaTypeAnyAudio with my media query. How can I ensure the MPMediaItem is one of the only audio types? enum { // audio MPMediaTypeMusic = 1 << 0, MPMediaTypePodcast = 1 << 1, MPMediaTypeAudioBook = 1 << 2, MPMediaTypeAudioITunesU = 1 << 3, // available in iOS 5.0 MPMediaTypeAnyAudio = 0x00ff, // video (available in

For my application, I need to decode an MP3 file which is stored in an NSData object. For security reasons, it is undesirable to write the NSData object to disk and re-open it using a System URL reference, even if its only locally stored for a few moments. I would like to take advantage Extended Audio File Services (or Audio File Services) to do this, but I'm having trouble getting a representation of the NSData, which exists only in memory, that can be read by these Audio File Services. Edit: I want to decode the MP3 data so I can get access to linear, PCM audio samples for manipulation.