The following code plays multiple audio files in a loop in iOS 11 but not in iOS 10. Seems like that AKSequencer cannot loop in iOS 10?
let mixer = AKMixer()
var sequencer: AKSequencer = AKSequencer()
sequencer.loadMIDIFile(fromUrl: URL(fileURLWithPath: midiFile))
for index in 0..<sequencer.tracks.count {
let musicTrack: AKMusicTrack = sequencer.tracks[index]
let sampler = AKMIDISampler()
if index < samples.count {
sampler.loadWavFromAbsolutePath(samples[index])
sampler.enableMIDI(midi.client, name: "Sampler_\(index)")
mixer.connect(input: sampler)
}
musicTrack.setMIDIOutput(sampler.midiIn)
}
AudioKit.output = mixer
AudioKit.start()
sequencer.enableLooping()
sequencer.play()
I can only guess what connection this might have to iOS 10, but I've had issues in the past where AKSequencer didn't loop when the its .play() call followed immediately after AudioKit.start(). I found that putting the .play() call in an IBAction or calling it from a timer (delayed 100ms or so) allowed it to loop properly.
I had a similar issue and the problem was related to the scope of the AKSequencer property.
It looks like the sequencer gets de-initialized and cannot process the MIDI signals any further.
Try to to upgrade the var sequencer: AKSequencer = AKSequencer() to a global variable.
Related
Thanks for AudioKit !
I have next question:
I'm trying to get ideal sync playing of AKSampleMetronome and one midi file wrapped in AKMIDISampler. Here is my code:
let metronome = AKSamplerMetronome()
let mixer = AKMixer()
let midiSampler = AKMIDISampler()
midiSampler.samplerUnit.loadSoundBankInstrument(....)
metronome >>> mixer
midiSampler >>> mixer
AudioKit.output = mixer
AudioKit.start()
let sequencer = AKAppleSequencer(filename: "midifilename")
sequencer.enableLooping()
sequencer.tracks[1].setMIDIOutput(midiSampler.midiIn)
//now play
sequencer.play()
metronome.beatTime = 0
metronome.play()
But when I'm changing tempo like this:
sequencer.setTempo(bpm)
let now = AVAudioTime(hostTime: mach_absolute_time())
metronome.setTempo(Double(bpm), at: now)
After a while the sound of metronome and midi sequencer diverges.
How can I achieve accurate solution for this ?
Lots of ways to do this but I would make one of the tracks in the sequencer a metronome track and send that midi signal to a midiSampler.
I want to play an Audio file (A wav file for example) and at specific locations of the track I want to fire events or triggers that will control an external device.
My idea for now is to generate a MIDI track that plays in sync with the Audio Track and when the MIDI track notes are played, some trigger events are generated that we can handle to do whatever we want.
The thing where I am stuck right now is how to play the .mid file and generate events when midi notes are played. I also want to play the wav and the mid file in sync, but that is not what I am solving at this point.
I looked into AudioKit, but the examples seem out of date and the documentation isn't helping a lot.
Is MIDI a right approach to do this? is there an easier way in iOS where I don't have to use AudioKit and just use something from AVFoundation.
I want to understand what tool is best to detect when a midi note from the .mid file is played and handle the event.
My research has pointed me to use AKAppleSequencer. What could help is a simple example that loads a midi file and then basically prints something when a note is played.
I came across these posts,
How to connect AKSequencer to a AKCallbackInstrument?
Play MIDI file together with wav AudioKit
but the AKSequencer is now replaced by AKAppleSequencer.
So I figured it out. The answer was basically in the posts above just updated the code so it uses AKAppleSequencer.
let sequencer = AKAppleSequencer(filename: "SaReGaMa") // the .mid file
let callbackInstr = AKMIDICallbackInstrument()
var player: AKPlayer!
func initializeSession() {
callbackInstr.callback = myCallBack
sequencer.setGlobalMIDIOutput(callbackInstr.midiIn)
if let audioFile = try? AKAudioFile(readFileName: "SaReGaMa.wav") {
player = AKPlayer(audioFile: audioFile)
player.completionHandler = { print("Finished playing file")}
player.buffering = .always
AudioKit.output = player
do {
try AudioKit.start()
} catch {
print("Error starting audiokit, \(error)")
}
}
}
// The callback gets triggered when each midi note is played by the sequencer.
func myCallBack(a: UInt8, b:MIDINoteNumber, c:MIDIVelocity) -> () {
print(a,b,c);
}
// These functions let you control the playback.
func play() {
player.play()
sequencer.play()
}
func pause() {
sequencer.stop()
player.pause()
}
I'm on AudioKit 4.9.1 and can't manage to play a MIDI file with the new AKSequencer (replacing AKAppleSequencer). No sound playing. Assume that MIDI file AND samples are loaded correctly since they previously worked with AKAppleSequencer. Background audio mode capability is also enabled.
Here's the relevant code: (I've also tried both AKSampler and AKAppleSampler but same result)
class MIDIPlayer {
var sampler: AKSampler
var legacySampler: AKAppleSampler
var sequencer: AKSequencer
init(withSfz sfz: String, orSf2 sf2: String, andMidiFile midiFile: String) {
self.sampler = AKSampler()
self.legacySampler = AKAppleSampler()
try? legacySampler.loadSoundFont(sf2, preset: 0, bank: 0)
sampler.loadSFZ(url: Bundle.main.url(forResource: sfz, withExtension: "sfz")!)
AudioKit.output = sampler
try? AudioKit.start()
sequencer = AKSequencer(targetNode: sampler)
// sequencer = AKSequencer(targetNode: legacySampler)
let midi = AKMIDIFile(url: Bundle.main.url(forResource: midiFile, withExtension: "mid")!)
sequencer.load(midiFile: midi)
}
func play() {
sequencer.playFromStart()
}
Is there some difference in how to set up the signal chain that I'm missing?
With the new sequencer, it has to be part of the signal chain. So, do something like
let mixer = AKMixer
sampler >>> mixer
for track in sequencer.tracks { track >>> mixer }
AudioKit.output = mixer
and it should work. Sorry for the delay in seeing this on Github issues.
I’m having a problem using AKMIDISampler in my project when there’s an initialized AKMicrophone. Along with correctly playing the woodblock sample when “play” is called on the sampler, the first time “play” is called a constant sine wave starts playing - it never stops.
I’ve replicated the problem in the smallest amount of code below. Issue happens when the class is initialized then playTestSample() is called.
Note that if the AKMicrophone related code is all muted the AKMIDISampler plays fine and the sine wave that currently haunts my dreams doesn’t happen.
(I’ve tried switching to use the AKSampler() just to see if the problem would exist there but I haven’t been able to get any sound out of that).
Fyi: I have “App plays audio or streams audio/video using AirPlay” in the “Required background modes” in info.plist - which is know to fix another sine wave issue.
Thank you very much for any assistance.
Btw: AudioKit rocks and has been a massive help on this project! :^)
AK 4.5.4
Xcode 10.1
import Foundation
import AudioKit
class AudioKitTESTManager {
var mixer = AKMixer()
var sampler = AKMIDISampler()
var mic = AKMicrophone()
var micMixer = AKMixer()
var micBooster = AKBooster()
init() {
mixer = AKMixer(sampler, micBooster)
do {
let woodblock = try AKAudioFile(readFileName: RhythmGameConfig.woodblockSoundName)
try sampler.loadAudioFiles([woodblock])
} catch {
print("Error loading audio files into sampler")
}
micMixer = AKMixer(mic)
micBooster = AKBooster(micMixer)
micBooster.gain = 0.0
AudioKit.output = mixer
AKSettings.playbackWhileMuted = true
AKSettings.defaultToSpeaker = true
AKSettings.sampleRate = 44100
do {
print("Attempting to start AudioKit")
try AudioKit.start()
} catch {
AKLog("AudioKit did not start!")
}
}
func playTestSample() {
// You hear the sample and a continuous sine wave starts playing through the samplerMixer
try? sampler.play(noteNumber: 60, velocity: 90, channel: 1)
}
}
Wheeew. I believe I've found a solution. Maybe it will help out someone else?
It seems that loading the files into the sampler AFTER AudioKit.start() fixes the Sine Wave of Terror!
//..
do {
print("Attempting to start AudioKit")
try AudioKit.start()
} catch {
AKLog("AudioKit did not start!")
}
do {
let woodblock = try AKAudioFile(readFileName: RhythmGameConfig.woodblockSoundName)
try sampler.loadAudioFiles([woodblock])
} catch {
print("Error loading audio files into sampler")
}
I'm having a problem with recording audio from the microphone of my test device to a .caf file in Swift, XCode 9.4.1 using the latest version of AudioKit. In a simple test whereby I send the audio straight from the microphone to the output via an AKBooster, it works just fine and I can hear the mic input coming out of the speakers. I'm more or less following this example, although again using a booster node instead of an oscillator.
The following is my code:
class MicrophoneHandler
{
var microphone : AKMicrophone!
var booster : AKBooster!
var mixer : AKMixer!
var recorder : AKNodeRecorder!
var file : AKAudioFile!
var player : AKAudioPlayer!
init()
{
setupMicrophone()
microphone = AKMicrophone()
booster = AKBooster(microphone) // Stereo amplifier for microphone
mixer = AKMixer(booster)
file = try! AKAudioFile() // File to store recorder output
player = try? AKAudioPlayer(file: file) // Player to play back recorded audio file
//player.looping = true
recorder = try? AKNodeRecorder(node: mixer, file: file)
try? recorder.record()
sleep(5)
let dur = String(format: "%0.3f seconds", recorder.recordedDuration)
print("Stopped. (\(dur) recorded)")
recorder.stop()
//file.exportAsynchronously(name: "Test", baseDir: .documents, exportFormat: .caf){ [weak self] _, _ in
//}
//player.play()
//AudioKit.output = player!
//try? AudioKit.start()
}
func setupMicrophone()
{
// Function to initialise microphone settings
// Adapted from AudioKit example code found here:
// https://audiokit.io/examples/MicrophoneAnalysis
AKSettings.bufferLength = .medium
AKSettings.ioBufferDuration = 0.002 // TODO experiment with this to control latency
do
{
try AKSettings.setSession(category: .playAndRecord, with: .allowBluetoothA2DP) // Set session type & allow streaming to Bluetooth devices
} catch
{
AKLog("Could not set session category.")
}
AKSettings.defaultToSpeaker = true // Output to speaker when audio input is enabled
}
}
I have commented out the export code as the problem doesn't appear to be here. The console displays the following:
AKMicrophone.swift:init():45:Mixer inputs 8
AKAudioPlayer.swift:updatePCMBuffer():533:AKAudioPlayer Warning: "BF848EC0-94F8-4E39-A211-784B001CED72.caf" is an empty file
2018-11-16 17:49:16.936169+0000 VoxBox[2258:6984570] Audio files cannot be non-interleaved. Ignoring setting AVLinearPCMIsNonInterleaved YES.
AKNodeRecorder.swift:record():104:AKNodeRecorder: recording
Stopped. (0.000 seconds recorded)
As you can see, the recorder appears not to be recording to file for some reason. To my mind, my code should
Initialise the microphone (including settings)
Route the microphone input through a booster followed by a mixer (mixing with an FX bank will happen later)
Create an empty .caf audio file to be written to
Set up a player to play this file when the time comes
Set up a recorder to record the output of the mixer node to the audio file
Record 5 seconds of microphone input to the audio file
Yet for some reason nothing is being recorded. Clearly I am missing something or have misunderstood how the AKNodeRecorder works in this regard. I have read as many StackOverflow questions on similar topics as I can, had a dig through the AudioKit documentation and read a couple of examples from the AudioKit site, but nothing seems to address my particular problem.
Any help would be much appreciated.