I'm working on an iOS/Flutter application, and am trying to work out if it's possible to play audio from the Music library on iOS with audio modifications (e. g. equalization settings) applied.
It seems like I'm looking for a solution that can work with MPMusicPlayerController, since that appears to be the strategy for playing local audio from the user's iOS Music library. I can find examples of applying EQ to audio on iOS (e. g. using AVAudioUnitEQ and AVAudioEngine: SO link, tutorial), but I'm unable to find any resources to help me understand if it's possible to bridge the gap between these resources.
Flutter specific context:
There are Flutter plugins that provide some of the functionality I'm looking for, but don't appear to work together. For example, the just_audio plugin has a robust set of features for modifying audio, but does not work with the local Music application on iOS/MPMusicPlayerController. Other plugins that do work with MPMusicPlayerController, like playify, do not have the ability to modify/transform the audio.
Even though I'm working with Flutter, any general advice on the iOS side would be very helpful. I appreciate any insight someone with more knowledge may be able to share with me!
Updating with my own answer here for future people: It looks like my only path forward (for now) is leaning into into AVAudioEngine directly. This is the rough POC that worked for me:
var audioPlayer = AVAudioPlayerNode()
var audioEngine = AVAudioEngine()
var eq = AVAudioUnitEQ()
let mediaItemCollection: [MPMediaItem] = MPMediaQuery.songs().items!
let song = mediaItemCollection[0]
do {
let file = try AVAudioFile(forReading: song.assetURL!)
audioEngine.attach(audioPlayer)
audioEngine.attach(eq)
audioEngine.connect(audioPlayer, to: eq, format: nil)
audioEngine.connect(eq, to: audioEngine.outputNode, format: file.processingFormat)
audioPlayer.scheduleFile(file, at: nil)
try audioEngine.start()
audioPlayer.play()
} catch {
// catch
}
The trickiest part for me was working out how to bridge together the "Music library/MPMediaItem" world to "AVAudioEngine" world -- which was just AVAudioFile(forReading: song.assetURL!)
Related
The app i'm writing contains 2 parts:
An audio player that plays stereo MP3 files
Video conferencing using webRTC
Each part works perfectly in isolation, but the moment i try them together, one of two things happens:
The video conference audio fades out and we just hear the audio files (in stereo)
We get audio output from both, but the audio files are played in mono, coming out of both ears equally
My digging had taken me down a few routes:
https://developer.apple.com/forums/thread/90503
&
https://github.com/twilio/twilio-video-ios/issues/77
Which suggest that the issue could be with the audio session category, mode or options.
However i've tried lots of the combos and am struggling to get anything working as intended.
Does anyone have a better understanding of the audio options to point in the right direction?
My most recent combination
class BBAudioClass {
static private var audioCategory : AVAudioSession.Category = AVAudioSession.Category.playAndRecord
static private var audioCategoryOptions : AVAudioSession.CategoryOptions = [
AVAudioSession.CategoryOptions.mixWithOthers,
AVAudioSession.CategoryOptions.allowBluetooth,
AVAudioSession.CategoryOptions.allowAirPlay,
AVAudioSession.CategoryOptions.allowBluetoothA2DP
]
static private var audioMode = AVAudioSession.Mode.default
static func setCategory() -> Void {
do {
let audioSession: AVAudioSession = AVAudioSession.sharedInstance()
try audioSession.setCategory(
BBAudioClass.audioCategory,
mode: BBAudioClass.audioMode,
options: BBAudioClass.audioCategoryOptions
)
} catch {
};
}
}
Update
I managed to get everything working as i wanted by:
Starting the audio session
Connecting to the video conference (at this point all audio is mono)
Forcing all output to the speaker
Forcing output back to the headphones
Obviously this is a crazy thing to have to do, but does prove that it should work.
But it would be great if anyone knew WHY this works, in order that i can actually get things to work properly first time without going through all these hacky steps
Note that this is NOT a duplicate of this SO Post because in that post only WHAT method to use is given but there's no example on HOW should I use it.
So, I have dug into AKOfflineRenderNode as much as I can and have viewed all examples I could find. However, my code never seemed to work correctly on iOS 10.3.1 devices(and other iOS 10 versions), for the result is always silent. I try to follow examples provided in other SO posts but no success. I try to follow that in SongProcessor but it uses an older version of Swift and I can't even compile it. Trying SongProcessor's way to use AKOfflineRenderNode didn't help either. It always turned out silent.
I created a demo project just to test this. Because I don't own the audio file I used to test with, I couldn't upload it to my GitHub. Please add an audio file named "Test" into the project before compiling onto an iOS 10.3.1 simulator. (And if your file isn't in m4a, remember to change the file type in code where I initialize AKPlayer)
If you don't want to download and run the sample, the essential part is here:
#IBAction func export() {
// url, player, offlineRenderer and others are predefined and connected as player >> aPitchShifter >> offlineRenderer
// AudioKit.output is already offlineRenderer
offlineRenderer.internalRenderEnabled = false
try! AudioKit.start()
// I also tried using AKAudioPlayer instead of AKPlayer
// Also tried getting time in these ways:
// AVAudioTime.secondsToAudioTime(hostTime: 0, time: 0)
// player.audioTime(at: 0)
// And for hostTime I've tried 0 as well as mach_absolute_time()
// None worked
let time = AVAudioTime(sampleTime: 0, atRate: offlineRenderer.avAudioNode.inputFormat(forBus: 0).sampleRate)
player.play(at: time)
try! offlineRenderer.renderToURL(url, duration: player.duration)
player.stop()
player.disconnectOutput()
offlineRenderer.internalRenderEnabled = true
try? AudioKit.stop()
}
I have integrated amazon polly to one of my project in swift and asking it to TTS multiple set of text strings. Certainly I am using there below set of instructions to play sound:
builder.continueOnSuccessWith { (awsTask: AWSTask<NSURL>) ->
Any? in
// The result of getPresignedURL task is NSURL.
// Again, we ignore the errors in the example.
let url = awsTask.result!
// Try playing the data using the system AVAudioPlayer
self.audioPlayer.replaceCurrentItem(with: AVPlayerItem(url: url as URL))
self.audioPlayer.play()
return nil
}
While debug I found that replaceCurrentItem is adding a new item to play and ignoring the previous. I would like to have some suggestions as how the polly handle such multiple calls within its framework.
Any help appreciated! Thanks
I could able to make this work by inserting each operation to AVQueuePlayer and playing at last, but I am keen to know how amazon handle's multiple file play in polly
Im new to swift but i like it more than obj-c as it looks a bit like java does to me from syntax wise compared to obj-c.
My problem is now that most of the source code samples are for obj-c so theyre unreadable for me =)
Anyway i managed to run a few code snippets like this(im not at my mac but they were similar):
let steamingURL:NSURL = NSURL(string: "http://....")!
let player = AVPlayer(URL: steamingURL)
player.allowsExternalPlayback = false
PlayWorkoutViewController.playerController = AVPlayerViewController()
PlayWorkoutViewController.playerController.player = player
self.addChildViewController(PlayWorkoutViewController.playerController)
self.view.addSubview(PlayWorkoutViewController.playerController.view)
PlayWorkoutViewController.playerController.view.frame = videoContainerView.frame
PlayWorkoutViewController.playerController.showsPlaybackControls = false
player.play()
resulting in a Play Button with a line trough it, it doesnt play the Stream.
The stream source is a mpg1/2 stream according to VLCPlayer and its coming from a Linux based satellite receiver.
Another thing i tried was to change that "string:" part to "fileURLWithPath:" at the NSURL variable but that didnt work either.
Is there a way to Buffer the stream or is this just a codec issue, what workaround options do i have?
Im hesitating since three days, i hope its not a duplicate question, thanks.
EDIT: content of the stream.m3u file:
EXTM3U
EXTVLCOPT--http-reconnect=true 192.168.178.20:8001/1:0:1:445D:453:1:C00000:0:0:0:
Security setting might be the problem. Go to info.plist and Add "App Transport Security Settings". Under that add "Allow Arbitrary Loads" and set it to YES. I hope this fixes the problem.
I am in the process of developing a game for iOS 9+ using Sprite Kit and preferably using Swift libraries.
Currently I'm using a Singleton where I preload my audio files, each connected to a separate instance of AVAudioPlayer.
Here's a short code-snipped to get the idea:
import SpriteKit
import AudioToolbox
import AVFoundation
class AudioEngine {
static let sharedInstance = AudioEngine()
internal var sfxPing: AVAudioPlayer
private init() {
self.sfxPing = AVAudioPlayer()
if let path = NSBundle.mainBundle().pathForResource("ping", ofType: "m4a") {
do {
let url = NSURL(fileURLWithPath:path)
sfxPing = try AVAudioPlayer(contentsOfURL: url)
sfxPing.prepareToPlay()
} catch {
print("ERROR: Can't load ping.m4a audio file.")
}
}
}
}
This Singleton is initialised during app start-up. In the game-loop I then just call the following line to play a specific audio file:
AudioEngine.sharedInstance.sfxPing.play()
This basically works, but I always get glitches when a file is played and the frame rate drops from 60.0 to 56.0 on my iPad Air.
Someone any idea how to fix this performance issue with AVAudioPlayer ?
I also watched out for 3rd party libraries, namely:
AudioKit [Looks very heavy-weighted]
ObjectAL [Last Update 2013 ...]
AVAudioEngine [Based on AVAudioPlayer, same problems ?]
Requirements:
Play a lot of very short samples (like shots, hits, etc..)
Play some motor effects (thus pitching would be nice)
Play some background / ambient sound in a loop
NO nasty glitches / frame rate drops !
Could you recommend any of the above mentioned libraries for my requirements or point out the problems using the above code ?
UPDATE:
Playing short sounds with:
self.runAction(SKAction.playSoundFileNamed("sfx.caf", waitForCompletion: false))
does indeed improve the frame rate. I exported the audio files with Audiacity to the .caf format (Apple's Core Audio Format). But in the tutorial, they export with "Signed 32-bit PCM" encoding which led to disturbed audio playback in my case. Using any of the other encoding options (32-bit float, U-Law, A-Law, etc..) worked fine for me.
Why using caf format? Because it's uncompressed and thus loaded faster into memory with less CPU overhead compared to compressed formats like m4a. For short sound effects played a lot in short intervals, this makes sense and disk usage is not affected much for short audio files consuming few kilobytes. For bigger audio files, like ambient and background music, using compressed formats (mp3, m4a) is obviously the better choice.
According to your question, if you develop a game for iOS 9+, you can use the new iOS 9 library SKAudioNode (official Apple doc):
var backgroundMusic: SKAudioNode!
For example you can add this to didMoveToView():
if let musicURL = NSBundle.mainBundle().URLForResource("music", withExtension: "m4a") {
backgroundMusic = SKAudioNode(URL: musicURL)
addChild(backgroundMusic)
}
You can also use to play a simple effect:
let beep = SKAudioNode(fileNamed: "beep.wav")
beep.autoplayLooped = false
self.addChild(beep)
Finally, if you want to change the volume:
beep.runAction(SKAction.changeVolumeTo(0.4, duration: 0))
Update:
I see you have update your question speaking about AVAudioPlayer and SKAction. I've tested both of them for my iOS8+ compatible games.
About AVAudioPlayer, I personally use a custom library maked by me based from the old SKTAudio.
I see your code, about AVAudioPlayer init, and my code is different because I use:
#available(iOS 7.0, *)
public init(contentsOfURL url: NSURL, fileTypeHint utiString: String?)
I don't know if fileTypeHint make the difference, so try and fill me about your test.
Advantages about your code:
With a shared instance audio manager based to AVAudioPlayer you can control volume, use your manager wherever you want, ensure compatibility with iOS8
Disadvantages about your code:
Everytime you play a sound and you want to play another sound, the previous is broken, especially if you have launch a background music.
How to solve? According with this SO post to work well without issues seems AVFoundation is limited to 4 AVAudioPlayer properties instantiables, so you can do this:
1) backgroundMusicPlayer: AVAudioPlayer!
2) soundEffectPlayer1: AVAudioPlayer!
3) soundEffectPlayer2: AVAudioPlayer!
4) soundEffectPlayer3: AVAudioPlayer!
You could build a method that switch through the 3 soundEffect to see if is occupied:
if player.playing
and use the next free player. With this workaround you have always your sound played correctly, even your background music.