I'm trying to use AKSampler on a simple iOS project to load a file and play it when tapping the device's screen.
I did the same steps with AKSamplePlayer and it worked fine, But I rather use the AKSampler, and also I get a strong feeling of missing something.
I've tried the play() method, and also the one with the midi note.
Which one is right? Do they both work?Besides, AudioKit looks so promising.
Here is my code:
import UIKit
import AudioKit
class ViewController: UIViewController
{
var sampler = AKSampler()
var tapRecognizer = UITapGestureRecognizer()
override func viewDidLoad()
{
super.viewDidLoad()
do
{
let file = try AKAudioFile(readFileName: "AH_G2.wav")
try sampler.loadAudioFile(file)
}
catch
{
print("No Such File...")
}
view.addGestureRecognizer(tapRecognizer)
view.isUserInteractionEnabled = true
tapRecognizer.addTarget(self, action: #selector(viewTapped))
AudioKit.output = sampler
AudioKit.start()
}
#objc private func viewTapped()
{
sampler.play(noteNumber: 60, velocity: 80, channel: 0)
print("tapped...")
}
}
Edit:
My problem is actually with the loadAudioFile method, the AKAudioFile itself is good, and the AKSampler plays a default sine sound.
I tried also the AKAudioFile methods for creating player and sampler didn't.
let file = try AKAudioFile (readFileName: "AH_G2.wav")
player = file.player
sampler = file.sampler
I also tried to add the wav file using the menu, no change.
If you look at the implementation, there is just the one play() method, but it has default values for noteNumber, velocity, and channel:
#objc open func play(noteNumber: MIDINoteNumber = 60,
velocity: MIDIVelocity = 127,
channel: MIDIChannel = 0) {
samplerUnit.startNote(noteNumber, withVelocity: velocity, onChannel: channel)
}
Changing the MIDI note will change the pitch/speed of the sample playback (60 is standard, 72 is double speed, 48 would be half speed etc), and changing the velocity will change the volume.
NB: the title of your post is 'AKSampler doesn't play', but I ran your code (changing the sample, of course) and it played just fine on my iPad.
I've tried a different audio file and it worked fine.
The first file was a mono file, so my conclusion here is that the AKSampler does not support mono files. Would love to hear more on that.
Related
i'm currently working a musician app. In my app notes should be played with a specific duration. I don't get into detail when the notes are played. Basically there is a ui view (a vertical line) which is moving and when this hits my other ui views (rectangle) it should be played a note. Important here: the note should be played until the line is not hitting the rectangle anymore.
The note playing is no problem but I don't find any duration. Also it should be possible to play the same note multiple times with a delay.
So I tried to make this work with AudioKit cause it's seems like the best greatest solution for audio. But it has so much stuff. I took a look into their examples and found this:
let bundlePath = Bundle.main.bundlePath
let soundPath = ("\(bundlePath)/sounds")
let akSampler = AKAppleSampler()
let mixer = AKMixer(akSampler)
try! akSampler.loadSoundFont(soundPath, preset: 0, bank: 0)
mixer.start()
AudioKit.output = mixer
do {
_ = try AudioKit.engine.start()
} catch {
print("AudioKit wouldn't start!")
}
do {
try akSampler.play(noteNumber: myNote.rawValue, velocity: 100, channel: 1)
} catch let e{
print(e)
}
Unfortunately I can't pass any duration and when I call akSampler.stop(noteNumber: myNote.rawValue) it also stops the other notes with the same type.
I tried to find a solution with AVFoundation like so:
engine = AVAudioEngine()
sampler = AVAudioUnitSampler()
engine.attach(sampler)
engine.connect(sampler, to: engine.mainMixerNode, format: nil)
guard let bankURL = Bundle.main.url(forResource: "sounds", withExtension: "SF2") else {
print("could not load sound font")
return
}
... init engine
sampler.startNote(60, withVelocity: 64, onChannel: 0)
But same result. Also the same case that I can't pass any duration.
I also digged into MIDISequencer's but it seems that they generating a sequence which I can play but this does not fit on my problem.
Does someone has a solution here?
The laziest solution would be to just schedule a stop with asyncAfter when you trigger the note, e.g.,
func makeNote(note: MIDINoteNumber, dur: Double) {
sampler.play(noteNumber: note, velocity: 100, channel: 0)
DispatchQueue.main.asyncAfter(deadline: .now() + dur) {
self.sampler.stop(noteNumber: note)
}
}
A better solution would probably use either AKSequencer or AKAppleSequencer. Both allow you to create sequences on the fly by adding individual notes with a specified duration (in musical time, i.e., number of beats). AKSequencer is considerably more accurate, but AKAppleSequencer has more readily available code examples on the web. A little confusingly, the current AKAppleSequencer used to also be called AKSequencer, but their interfaces are sufficiently different that a quick look at the docs for the two classes will tell you which you're looking at.
Your question is asking about how to schedule MIDI events which is precisely what these classes are designed to do. You haven't really given a clear reason why generating a sequence doesn't fit your problem.
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 implementing an app utilizing AudioKit that allows you to play a large number of audio files and switch between them at any time. Additionally we need one audio file to play on loop for ambient noise.
What is the correct way to dynamically change players in AudioKit's output? Or what's the proper way to implement this behavior?
AudioKit requires you set its output which can be an AKPlayer that plays one audio file or an AKMixer given an array of AKPlayers for example. You cannot change the output once AudioKit has been started as I saw previously. So currently my approach is to use AKMixer to play two AKPlayers - one for the current file and one for the ambient noise. When the user taps the 'Next' button I stop() AudioKit, recreate an AKMixer with a new player for the next song's audio file and the ambient noise player, assign that to output, start() AudioKit, and play both players. This results in undesirable behavior because playback of the ambient noise is stopped when switching songs resulting in a brief pause.
If this is the correct approach, how can we update the output without stopping AudioKit? I wondered if you can initialize the mixer with an array of players that's a strongly held property and simply add/remove players in the array. But that doesn't work - starting a new player throws an error player started when in a disconnected state because this node is not attached to the output.
I've created a sample project to demonstrate this behavior. When launched the app plays drums as ambient noise and waves for the current track. When you tap Next it'll switch to the next track (which in this demo code is just the same audio file) and you can hear the drums stop and then resume which is undesirable. I've included the project's code below:
final class Maestro: NSObject {
static let shared = Maestro()
private var audioPlayer: AKPlayer?
private var ambientPlayer: AKPlayer = {
let player = AKPlayer(url: Bundle.main.url(forResource: "drums", withExtension: "wav")!)!
player.isLooping = true
return player
}()
private var mixer: AKMixer?
private let audioFileURL = Bundle.main.url(forResource: "waves", withExtension: "mp3")!
func play() {
playNewPlayer(fileURL: audioFileURL)
}
func next() {
//In the real app we'd play the next audio file in the playlist but for the demo we'll just play the same file
playNewPlayer(fileURL: audioFileURL)
}
private func playNewPlayer(fileURL: URL) {
audioPlayer?.stop()
audioPlayer = nil
do {
try AudioKit.stop()
} catch {
print("Maestro AudioKit.stop error: \(error)")
}
audioPlayer = AKPlayer(url: fileURL)!
mixer = AKMixer([audioPlayer!, ambientPlayer])
AudioKit.output = mixer
do {
try AudioKit.start()
} catch {
print("Maestro AudioKit.start error: \(error)")
}
if ambientPlayer.isPlaying {
//need to resume playback from current position
let pos = ambientPlayer.currentTime
ambientPlayer.stop()
ambientPlayer.play(from: pos)
} else {
ambientPlayer.play()
}
audioPlayer?.play()
}
}
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")
}
First, I called a AKMIDISampler to play an audio file, and then assigned it to AKSequencer. The 'midi' file I used is just a 2 bars long, C3 note, single track midi file, exactly as long as the audio file I wanted to play. But, in calling AKAudioFile, I wanted to choose mp3 file randomly. I temporarily made 1.mp3, 2.mp3 and 3.mp3 as below.
let track = AKMIDISampler()
let sequencer = AKSequencer(filename: "midi")
try? track.loadAudioFile(AKAudioFile(readFileName: String(arc4random_uniform(3)+1) + ".mp3"))
sequencer.tracks[0].setMIDIOutput(track.midiIn)
// Tempo track I had to made to remove sine wave
sequencer.tracks[1].setMIDIOutput(track.midiIn)
And did some sequencer settings,
sequencer.setTempo(128.0)
sequencer.setLength(AKDuration(beats: 8))
sequencer.setLoopInfo(AKDuration(beats: 8), numberOfLoops: 4)
sequencer.preroll()
and assigned AKMIDISampler to AudioKit.output, then did sequencer.play().
The sequencer playback was successful! It loaded among three mp3 files randomly, and played 8 beats (2 bars), looped for 4 times exactly.
But my goal is to load random MP3 files every time the loop repeats. It seems like the sequencer only plays the first assigned mp3 file when looping. I am struggling finding a solution to this.
Perhaps I could use "AKCallbackInstrument"? Since I play audiofile through a midi note in this case, I might reset "loadAudioFile" whenever the midi note is off? In that way I might loop the sequencer and play random a audio file in every loop. This is just an idea, but for me now it is hard to write it properly. I hope I am on the right track. It would be great if I could get an advice here. <3
You're definitely on the right track - you can easily get random audio files to loop at a fixed interval with AKSequencer + AKCallbackInstrument. But I wouldn't worry about trying to reload on the NoteOff message.
I would first load each mp3 into a separate player (e.g., AKAppleSampler) in an array (e.g.,you could call it players) and create a method that will trigger one of these players at random:
func playRandom() {
let playerIndex = Int(arc4random_uniform(UInt32(players.count)))
try? players[playerIndex].play()
}
When you create your sequencer, add a track and assign it to an AKCallbackInstrument. The callback function for this AKCallbackInstrument will call playRandom when it receives a noteOn message.
seq = AKSequencer()
track = seq.newTrack()!
callbackInst = AKCallbackInstrument()
track.setMIDIOutput(callbackInst.midiIn)
callbackInst.callback = { status, note, vel in
guard status == .noteOn else { return }
self.playRandom()
}
It isn't necessary to load the sequencer with a MIDI file. You could just add the triggering MIDI event directly to the track.
track.add(noteNumber: 48, // i.e., C3
velocity: 127,
position: AKDuration(beats: 0), // noteOn message here
duration: AKDuration(beats: 8), // noteOff 8 beats later
channel: 0)
Your problem with the sine wave is probably being caused by an extra track (probably tempo track) in the MIDI file which you created which hasn't been assigned an output. You can avoid the problem altogether by adding the MIDI events directly.
In principle, you could use the callback to check for noteOff events and trigger code from the noteOff, but I wouldn't recommend it in your case. There is no good reason to re-use a single player for multiple audiofiles. Loading the file is where you are most likely to create an error. What happens if your file hasn't finished playing and you try to load another one? The resources needed to keep multiple players in memory is pretty trivial - if you're going to play the same file more than once, it is cleaner and safer to load it once and keep the player in memory.
It was very helpful, c_booth! Thanks to you, I made a huge progress today. Here's what I've written based on your advise. First, I made an array of AKPlayers include 6 mp3 files. They're assigned to AKMixer, and then I called sequencer and callback instrument. I made a track and a note on the sequencer, which calls 'playRandom' function on every noteOn :
let players: [AKPlayer] = {
do {
let filenames = ["a1.mp3", "a2.mp3", "a3.mp3", "b1.mp3", "b2.mp3", "b3.mp3"]
return try filenames.map { AKPlayer(audioFile: try AKAudioFile(readFileName: $0)) }
} catch {
fatalError()
}
}()
func playRandom() {
let playerIndex = Int(arc4random_uniform(UInt32(players.count)))
players[playerIndex].play()
}
func addTracks() {
let track = sequencer.newTrack()!
track.add(noteNumber: 48, velocity: 127, position: AKDuration(beats: 0), duration: AKDuration(beats: 16), channel: 0)
track.setMIDIOutput(callbackInst.midiIn)
callbackInst.callback = { status, note, vel in
guard status == .noteOn else { return }
self.playRandom()
}
}
func sequencerSettings() {
sequencer.setTempo(128.0)
sequencer.setLength(AKDuration(beats: 16))
sequencer.setLoopInfo(AKDuration(beats: 16), numberOfLoops: 4)
sequencer.preroll()
}
func makeConnections() {
players.forEach { $0 >>> mixer }
}
func startAudioEngine() {
AudioKit.output = mixer
do {
try AudioKit.start()
} catch {
print(error)
fatalError()
}
}
func startSequencer() {
sequencer.play()
}
This worked great. It randomly selects one from 6 mp3 files (they are all the same length, 128bpm and 16 beats). What I found strange here is, though, the first playback plays two audio files at once. It works fine after the second loop. I changed the numberOfLoop setting, enableLooping(), etc but still the same - plays two files on the first playback. The trackcount is still 1, and I only called one AKPlayer as you could see. Is there anything I can do about this?
Also, ultimately, I'd like to call hundreds of mp3 files on the array, as what I'm trying to make is a sort of DJing app (something like Ableton Live preset). Do you think it's a good idea to use AKPlayer, assuming this code will load mp3 files from the cloud and stream it to the user? Much appreciated. <3