It appears that AVAudioPlayer is not reentent. So in the following would soundfx play to completion, delay 1 second, then play again, rather then the 1 second delay - and resultant overlapping playback I desire:
// ...
AVAudioPlayer* soundfx = [[AVAudioPlayer alloc] initWithContentsOfURL:soundURL error:nil];
(void) makeSomeNoise {
[soundfx play];
sleep(1);
[soundfx play];
}
Must I then resort to NSOperation - threading - to achieve my goal of overlapping playback?
Note: I am using IMA4/ADPCM format which is apparently the correct format for layered sound playback.
Cheers,
Doug
It's not that AVAudioPlayer is not reentrant. It is that AVAudioPlayer starts to play your sound after the runloop has ended, and not in your makeSomeNoise function. If you want to play your sound with a one second delay, you can do this:
(void) makeSomeNoise {
[soundfx play];
[soundfx performSelector:play withObject: nil afterDelay:1.0];
}
Related
I just created AVPlayer and it plays music well. I have two questions
How to play another music from another URL (should I stop current player?)
How to show current time of the song in UISlider (actually is it a method that called when the song is playing?)
Use -[AVPlayer replaceCurrentItemWithPlayerItem] to replace the current playing item reusing the player instance. You can create an item with an URL or with an asset.
In order to know when a given item finishes playing use the notification AVPlayerItemDidPlayToEndTimeNotification.
Use -[AVPlayer addPeriodicTimeObserverForInterval] to perform some action periodically while the player is playing. See this example:
[self.player addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(0.1, 100)
queue:nil
usingBlock:^(CMTime time) {
<# your code will be called each 1/10th second #>
}];
1) If you used - (id)initWithURL:(NSURL *)URL then you should stop player with pause, dealloc it and create new instance.
AVPlayer *player = [AVPlayer alloc] initWithURL:[NSURL URLWithString:#"http:/someurl.com"]];
[player play];
[player pause];
[player release];
player = [AVPlayer alloc] initWithURL:[NSURL URLWithString:#"http:/someurl2.com"]];
[player pause];
[player release];
If you used playerWithURL, then just call the same line again.
2). The easiest is the get duration of the current item https://stackoverflow.com/a/3999238/619434 and then update the UISlider with that value. You can use NSTimer to periodically check the duration.
self.player.currentItem.asset.duration
I have searched for this answer and have not found it.
I have music that plays in the background when my iPhone app is launched. But I want a button so that users can mute the music. There are sound effects within the app also so sliding the mute button on the side of the device won't cut it.
This is the current code I have for the AVAudioPlayer.
- (void)viewDidLoad{
#if TARGET_IPHONE_SIMULATOR
//here code for use when execute in simulator
#else
//in real iphone
NSString *path = [[NSBundle mainBundle] pathForResource:#"FUNKYMUSIC" ofType:#"mp3"];
AVAudioPlayer *TheAudio=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];
TheAudio.delegate = self;
[TheAudio play];
TheAudio.numberOfLoops = -1;
#endif
}
Can anyone help me out the code needed for a simple button to simply stop the music and start it again.
Thanks in advanced.
Put this code in the viewcontroller.h file:
-(IBAction) btnStop:(id)sender;
Put this code in the viewcontroller.m file:
-(IBAction) btnStop:(id)sender {
[TheAudio stop];
//Whatever else you want to do when the audio is stopped
}
In the Interface builder, connect a button to this action, so when it is clicked this action will be called.
That should make the music stop.
Its easier to display code in an answer:
-(IBAction) playerPlay:(id)sender {
if([player isPlaying]) {
[player stop];
}
if(![player isPlaying]) {
[player play];
}
}
I'll explain:
The [player isPlaying] method checks to see if the audio is playing. If the audio is playing, everything in the brackets is executed (in this situation, the audio stops playing).
Because of the "!" in ![player isPlaying], the method is made the opposite of what it usually is. This means that if the player is NOT playing, everything in the brackets is executed (in this situation, the audio starts playing).
All of this is enclosed in the IBAction, so that it is executed when the button is clicked.
For future reference, the correct format for an If statement in Objective-C is:
if(thing to check for) {
things that happen if the thing that is check for is correct;
}
The word "then" is never actually used, but it is the same thing and whatever is in the brackets.
Hope this helps!
I am trying to create a audio meter level while I am recording the user voice using avaudiorecorder. Can someone help me in that regard?
Actually, the code is pretty straightforward since AVAudioPlayer and AVAudioRecorder have built in methods to get you on your way. My approach was this:
make a repeating call to -updateMeters and the averagePowerForChannel: & peakPowerForChannel: methods and call a delegate method to notify the controlling object
Example:
NSOperationQueue *queue=[[NSOperationQueue alloc] init];
NSInvocationOperation *operation=[[NSInvocationOperation alloc] initWithTarget:self selector:#selector(updateMeter) object:nil];
[queue addOperation: operation];
and
-(void)updateMeter
{
do {
//don't forget:
[recorder updateMeters];
self.averagePower = [recorder averagePowerForChannel:0];
self.peakPower = [recorder peakPowerForChannel:0];
// we don't want to surprise a ViewController with a method call
// not in the main thread
[self.delegate performSelectorOnMainThread: #selector(meterLevelsDidUpdate:) withObject:self waitUntilDone:NO];
[NSThread sleepForTimeInterval:.05]; // 20 FPS
}while(someCondition);
}
If your View Controller implements the meterLevelsDidUpdate: method, you can use this method to update your Level Meter.
create a UIView subclass with a subview that changes its height according to the average or peak value(s). Adjust to taste.
Easy, you can use NSTimer for that:
- (void)startAudioMetering {
self.meterTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(updateAudioMeter)userInfo:nil repeats:YES];
}
- (void)stopAudioMetering {
[self.meterTimer invalidate];
}
- (void)updateAudioMeter { //called by timer
// audioRecorder being your instance of AVAudioRecorder
[self.audioRecorder updateMeters];
self.dBLevel = [self.audioRecorder averagePowerForChannel:0];
}
WARNING: While creating your AVAudioRecorder instance, you have to call meteringEnabled AFTER you call prepareToRecord or record, otherwise it won't updateMeters:
[self.audioRecorder prepareToRecord];
self.audioRecorder.meteringEnabled = YES;
Swift code based on Tom's answer:
NSOperationQueue().addOperationWithBlock({[weak self] in
repeat {
self?.audioRecorder.updateMeters()
self?.averagePower = self?.audioRecorder.averagePowerForChannel(0)
self?.peakPower = self?.audioRecorder.peakPowerForChannel(0)
self?.performSelectorOnMainThread(#selector(DictaphoneViewController.updateMeter), withObject: self, waitUntilDone: false)
NSThread.sleepForTimeInterval(0.05)//20 FPS
}
while (someCondition)
})
Do the meter UI stuff inside func updateMeter(){//UI stuff here}
Its pretty simple,
The values you get in the buffer are positive and negative (this is how the waves work) so if you do the average of that values it will give you a near 0 value.
So what you have to do is just put all values positive (with the Math.abs() function) and then do the avarage, it will return you the sound level.
Hope this helps ;)
You can also use ReactiveCocoa and make use of interval:onScheduler::
Returns a signal that sends the current date/time every interval on scheduler.
Using a single audio channel:
#weakify(self)
RACDisposable *metersDisposable = [[RACSignal // make sure you dispose it eventually
interval:0.1
onScheduler:[RACScheduler scheduler]]
subscribeNext:^(NSDate *) {
#strongify(self)
[recorder updateMeters];
auto averagePower = [recorder averagePowerForChannel:0];
auto peakPower = [recorder peakPowerForChannel:0];
// Inform the delegate or make other use of averagePower and peakPower
}];
I found the answer in following link.
AVMeter for AVPlayer
Though it requires lot of customizations but I feel I will be able to do it.
Alright I have two problems. I'm using AVAudioPlayer to play a simple audio file in .caf format. What I'm trying to do is have a play and pause button. Here is a sample of a simple IBAction to play the audio from a button.
- (IBAction) clear {
NSString *path = [[NSBundle mainBundle] pathForResource:#"clear" ofType:#"caf"];
AVAudioPlayer* myAudio=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];
myAudio.delegate = self;
myAudio.volume = 1.0;
myAudio.numberOfLoops = 0;
[myAudio play];
}
So when I go ahead and create another IBAction with the method...
- (IBAction) stopaudio {
[myAudio stop];
audioPlayer.currentTime = 0;
}
I compile and xcode tells me that myAudio in the stopaudio IBAction is not defined. How do I fix it so I'm able to access myAudio in another IBAction?
My Second question is that I'm using NavigationController to setup a TableView, when I make a selection it takes me to a UIView with a back button to go back to the TableView. What I'm trying to do is to kill any audio that I have playing in the UIView when I go back to the TableView. The code above is part of the code that I'm going to have in the UIView.
Also one quick question. Lets say I have an audio file that is 1 minute long. Clicking play again will overlap a new instance of that audio before the old instance is done playing. How can I check to see if myAudio is playing and not allow it to be played again until myAudio is finished playing?
Thank You!
First of all, you should read the documentation. It will remove almost all of your questions. Nevertheless, to have access to your instance of AVAudioPlayer from all methods of your class, you should define it in your .h file. To stop your player on returning to the previous screen, call [myAudio stop] in your viewWillDisappear:(BOOL)animated method. About your last question. If you define myAudio in your .h file, you will be able to check if it is playing now. smth like
- (IBAction) clear {
if(![myAudio isPlaying]){
[myAudio play];
}
}
I am implementing a sound effect that plays while a user is dragging a UISlider.
In a previous question, I used AudioServicesPlaySystemSound() but that type of sound can't be halted. I need the sound to halt when the user is not actively dragging the slider but has not released it.
Now I am creating a sound using an AVAudioPlayer object. I initialize it in my View Controller like this:
#interface AudioLatencyViewController : UIViewController <AVAudioPlayerDelegate> {
AVAudioPlayer *player1;
}
#implementation AudioLatencyViewController
#property (nonatomic, retain) AVAudioPlayer *player1;
#synthesize player1;
-(void)viewDidLoad {
[super viewDidLoad];
// the sound file is 1 second long
NSString *soundFilePath = [[NSBundle mainBundle] pathForResource:#"tone1" ofType:#"caf"];
NSURL *fileURL = [[NSURL alloc] initFileURLWithPath:soundFilePath];
AVAudioPlayer *newPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:fileURL error:nil];
[fileURL release];
self.player1 = newPlayer;;
[newPlayer release];
[self.player1 prepareToPlay];
[self.player1 setDelegate:self];
}
I have two methods to control the sound. The first one plays the sound whenever the slider is being moved. It is connected to the UISlider's Value Changed event in Interface Builder.
-(IBAction)sliderChanged:(id)sender;
{
// only play if previous sound is done. helps with stuttering
if (![self.player1 isPlaying]) {
[self.player1 play];
}
}
The second method halts the sound when the user releases the slider button. It's connected to the UISlider's Touch Up Inside event.
-(IBAction)haltSound;
{
[self.player1 stop];
}
This works when the slider button is moved then released quickly, but if you hold down the button longer than two or three seconds, the sound repeats (good) then breaks up (bad). From then on, the sound won't play again (super bad).
I have tried setting the sound to loop using:
[self.player1 setNumberOfLoops:30];
...but that leads to the app freezing (plus locking up the Simulator).
What can I do to debug this problem?
When a user is holding the UISlider, Value Changed gets called MANY MANY times (any time the user moves just a slight amount). I would use Touch Down instead.
You might want to still try using the loop for this route...
I like the idea of playing a sound while the user is moving the slider though. Let me know how it works out.
deggstand#gmail.com