Is it possible to know when an AVAudioPlayer is ready after a call to prepareToPlay?
If not, is there any other class that provides this functionality?
I would like to implement something like this:
- (void) prepare {
[audioPlayer prepareToPlay];
// Update UI to indicate that the audio is being prepared
}
- (void) onAudioReady {
// Update UI to indicate that the audio is ready
}
There is this class that can help to initialize the audio and then play it instantly in your onAudioReady method.
https://github.com/nicklockwood/SoundManager
with reference to this post: https://stackoverflow.com/a/10417762/1474080
OR
you can check for the BOOL result from [audioPlayer prepareToPlay] to see if the audio hardware has been initialised according to the documentation. If the result is YES, you could generate some UI for user to see.
prepareToPlay
Prepares the audio player for playback by preloading its buffers.
(BOOL)prepareToPlay Return Value Returns YES on success, or NO on failure.
Discussion Calling this method preloads buffers and acquires the audio
hardware needed for playback, which minimizes the lag between calling
the play method and the start of sound output.
Calling the stop method, or allowing a sound to finish playing, undoes
this setup.
Related
I am working in audio player module where it takes one audio file and playing. I am using AvAudioPlayer to play my audio file, it's working as expected and I am getting call backs once finished the audio playback. I have implemented looping by numberOfLoops property with negative value so far it's good. In a case I need call back once the current audio finishes playing first time. Is there any possible way to get call back or observer to notify me my audio played first time.
My idea is that we can achieve this by running a timer. What is the best approach?
Generic:
Each time completion of audio play back expecting a notification even it has infinite loop also.
first make numberofloops=0
use this delegate method so this method will call,
- (void) audioPlayerDidFinishPlaying: (AVAudioPlayer *) appSoundPlayer successfully: (BOOL) flag
then in that method u can make numberofloops= -1 so that u can get first notification and after loop continues. and [player play]..
and if u write numberofloops= 0 in audioPlayerDidFinishPlaying and play then each time audioPlayerDidFinishPlaying will call like loop..and you can get notification for each..
There are a lot of questions relating to background music playback in iOS on StackOverflow. None fully explore all edge cases, the aim of
this question is to be the final word in background audio question on
iOS
Definitions & Assumptions
All the code, questions and examples refer to ios5.
"background" — The state an app is put into when the user presses the home button or the power button (so the devices displays the lock screen). The app can also be put into background using the multitasking switcher or the multitasking gestures on iPad.
"audio" — Audio played back using AudioQueue (including AVAudioPlayer)
Prerequisites
As I understand it there are 2 requirements to get an app to play audio in the background.
Set UIBackgroundModes to audio in the Info.plist
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
Requirements
My use-case is playing relatively long audio in the background (music). There are potentially hundreds of tracks and the app will play them sequentially. It can be considered that the audio will play indefinitely.
The app will handle interruptions by pausing the playback.
Questions
I've had mixed success with:
[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:...];
Allowing audio to play in the background. But I'm confused as to if its required and how it differs to:
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
Edge Cases
Interruptions. If you register to be notified of audio interruptions (phone calls etc), by becoming the delegate of AVAudioPlayer. For example, if you then pause or stop your audio when an interruption starts and resume when it ends is your app suspended if the interruption exceeds 10 minutes (max time allowed for background tasks to complete)?
The Simulator will stop the audio if Lock or Home are invoked, while using:
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
However this works on a device. Is this a known issue?
I have some experience with GPS background mode, and background audio. This is not exactly the same as your situation (you want to play a long audio file, and I play short messages) but here's what I can tell you:
beginBackgroundTaskWithExpirationHandler This selector has one purpose when being invoked when in background: avoid the application to return to the suspended state in which no code can be invoked anymore (you're "frozen"). So as long as you invoked beginBackgroundTaskWithExpirationHandler and before you terminated your long running task with beginBackgroundTaskWithExpirationHandler, you use the CPU, and consume battery.
I really doubt that playing a file in the background should use the battery of the iPhone as if it was running an app so I doubt that beginBackgroundTaskWithExpirationHandler is really involved in your flow.
Simulator: don't rely on the simulator: it does not fully implement background modes. Actually, when you click on the home button, your app goes in background, but at this stage, you may still be able to execute code in your app. After a while, then, your app will be suspended (=frozen), and your code execution will be suspended in order to save the battery.
This suspended state will never occur on the simulator.
Interruptions. It's not up to you to pause/resume the playback when a phone call comes in. the platform is in charge of this, and you can just react to this with your AVAudioSessionDelegate . However, you can influence the way your session is going to interact with other audio sounds by setting property on your audio session (see kAudioSessionProperty_OverrideCategoryMixWithOthers for instance).
So the flow is more: your describe the way your audio session should interact with the rest of the system, the system will mix the sounds accordingly to that, and if your session gets interrupted, you'll be notified with the AVAudioSessionDelegate.
Hope this helps.
I have used below code to Device Control -
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
[self becomeFirstResponder];
Used to get register for listening the remote control.
Once done remove it -
[[UIApplication sharedApplication] endReceivingRemoteControlEvents];
[self resignFirstResponder];
make the App canBecomeFirstResponder-
- (BOOL)canBecomeFirstResponder {
return YES;
}
Used delegate method to handle iPhone control, like play and pause while doble tap on the home button
- (void)remoteControlReceivedWithEvent:(UIEvent *)event {
//if it is a remote control event handle it correctly
if (event.type == UIEventTypeRemoteControl) {
if (event.subtype == UIEventSubtypeRemoteControlPlay) {
[audioPlayer play];
NSLog(#"play");
} else if (event.subtype == UIEventSubtypeRemoteControlPause) {
[audioPlayer stop];
NSLog(#"pause");
} else if (event.subtype == UIEventSubtypeRemoteControlTogglePlayPause) {
NSLog(#"toggle");
}
}
}
I have a view controller that uses AVPlayer. this view controller can load a modal view controler where the user can record audio using AVAudioRecorder.
this is what happens:
if the user plays the composition in the fist controller with [AVPLayer play] the AVAudioRecorder will not record in the modal view controller. there are no errors but the current time returned by AVAudioRecorder is 0.0;
if the user dismisses the modal dialog and reloads it. AVAudioRecorder works fine.
this can be repeated over and over
AVAudioRecorder does not work the first time it is invoked after a [AVPlayer play] call
I have been fighting with this for days and just have reorganized my code related to both AVPlayer and AVAudioRecorder and it's still acting weird.
Any help or pointer is much appreciated
Thanks in advance
Jean-Pierre
I've been having the same problem too, and this is the solution I found.
When recording, write this line code after AVAudioRecord is initialized:
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryRecord error:NULL];
Then invoke record method.
How are you setting the AVAudioSession's category, i.e., play or record? Try something like
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
I've been having the same problem. I use AVPlayer to play compositions (previous recordings I've used AVAudioRecord for). However, I found that once I've used AVPlayer I could no longer use AVAudioRecorder. After some searching, I discovered that so long as AVPlayer is instantiated in memory and has been played at least once (which is usually what you do immediately after instantiating it) AVAudioRecorder will not record. However, once AVPlayer is dealloc'd, AVAudioRecorder is then free to record again. It appears that AVPlayer holds on to some kind of connection that AVAudioRecorder needs, and it's greedy...it won't let it go until you pry it from it's cold dead hands.
This is the solution I've found. Some people claim that instantiating AVPlayer takes too much time to keep breaking down and setting back up. However, this is not true. Instantiating AVPlayer is actually quite trivial. So also is instantiating AVPlayerItem. What isn't trivial is loading up AVAsset (or any of it's subclasses). You really only want to do that once. They key is to use this sequence:
Load up AVAsset (for example, if you're loading from a file, use AVURLAsset directly or add it to a AVMutableComposition and use that) and keep a reference to it. Don't let it go until you're done with it. Loading it is what takes all the time.
Once you're ready to play: instantiate AVPlayerItem with your asset, then AVPlayer with the AVPlayerItem and play it. Don't keep a reference to AVPlayerItem, AVPlayer will keep a reference to it and you can't reuse it with another player anyway.
Once it's done playing, immediately destroy AVPlayer...release it, set its var to nil, whatever you need to do. **
Now you can record. AVPlayer doesn't exist, so AVAudioRecorder is free to do its thing.
When you're ready to play again, re-instantiate AVPlayerItem with the asset you've already loaded & AVPlayer. Again, this is trivial. The asset has already been loaded so there shouldn't be a delay.
** Note that destroying AVPlayer may take more than just releasing it and setting its var to nil. Most likely, you've also added a periodic time observer to keep track of the play progress. When you do this, you receive back an opaque object you're supposed to hold on to. If you don't remove this item from the player AND release it/set it to nil, AVPlayer will not dealloc. It appears that Apple creates an intentional retain cycle you must break manually. So before you destroy AVPlayer you need to (example):
[_player removeTimeObserver:_playerObserver];
[_playerObserver release]; //Only if you're not using ARC
_playerObserver = nil;
As a side note, you may also have set up NSNotifications (I use one to determine when the player has completed playing)...don't forget to remove those as well.
If you need use AVPlayer and AVAudioRecorder at the same time do following:
set audio category to "play and record" (as described above or with C-based Audio Session Function)
"record" method must be invoked after invocation of "play" method with some delay. (I set 0.5 sec)
If you don't provide this, playback will start, but recording will not start.
shouldn't it be [AVAudioRecorder record]; instead of play?
I've had the same issue: AVAudioRecorder did not start recording.
My example is a bit different: I have a tabbar based app with several AVAudioPlayers in the different views. For the sake of the example, lets say that the first loaded view has 3 AVAudioPlayers, while the second view has one AVAudioPlayer and one AVAudioRecorder. They are all initiated in the viewDidLoad method.
The recorder was not working in second view. When I hit my record button, the view slightly shaked and the recording did not begin.
Strangely, the simulator worked fine and did not show the same symptoms... (anyone has an idea why?)
After some research and reading this thread I have realized that I have not set the players in the first view to nil, so I guess they were still in the memory preventing the recorder to start. Once I have set them to nil in the viewDidDisappear method, it was working alright again.
here is what helped me:
-(void)viewDidDisappear:(BOOL)animated {
firstPlayer = nil;
secondPlayer = nil;
thirdPlayer = nil;
}
ViewDidUnload did not help because the View, and therefore the variablbes in the class itself were not unloaded when switching views.
Hope this may be useful for others as well.
#Aaron Hayman explanation is accurate but the solution for me was very simple. Just implement the didFinishPlaying method of the player delegate and release the player there.
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
self.playerWord = nil;
}
Is it possible to handle interruption by AVPLayer delegate when I have more then one AVPlayer?
I have tried few things to start again two AVPlayer after phone call, but still only one respond and started, the second one was paused and did nothing.
My guess is that you need to keep an array of your players so that you can poll through them and pause/start each one. You can add each to an array when you create the player which you can access in audioPlayerBeginInterruption: and audioPlayerEndInterruption:
Apple's docs imply that the interruptions only handle one player ...if the class had stated a method input of players instead of player then I would have said you could have just done a for loop to poll through them like the code below:
AVAudioPlayer *player;
for (player in players) {
[player pause];
//or [player play];
}
http://developer.apple.com/iphone/library/documentation/AVFoundation/Reference/AVAudioPlayerDelegateProtocolReference/Reference/Reference.html#//apple_ref/occ/intfm/AVAudioPlayerDelegate/audioPlayerBeginInterruption:
I'm sure you've solved this already, but just wanted to log my answer anyway. I've just tested this on an IPhone (4.3.2), my application is playing two different sounds with two different AVAudioPlayers. When receiving a phone call I DO get an interruption for each player, for both interruption methods:
- (void)audioPlayerBeginInterruption:(AVAudioPlayer *) player;
- (void)audioPlayerEndInterruption:(AVAudioPlayer *) player;
So you can easily re-start both players:
- (void) audioPlayerEndInterruption:(AVAudioPlayer *) player {
NSLog (#"Interruption ended. Resuming audio playback.");
[player prepareToPlay];
[player play];
}
I'm using the AVAudioPlayer to play sound FX on a separate thread in my app. Right now my app is fairly simple, I have a UIScrollView for a scrolling background, and a couple of CALayers that represent a player and an enemy in a simple side-scroller type game (think Mario or Kung Fu or whatnot)...I can move the player left and right, with the view scrolling appropriately with no problems. I have an "attack" button that's playing a sound effect...and many times when I play the sound effect, I get a little bit of a hitch, graphically. Is this just par for the course on the iPhone using Quartz? Is there some way to have this perform a little more smoothly without starting to investigate OpenGL?
Use NSData dataWithContentsOfMappedFile instead of dataWithContentsOfFile.
Also AVAudioPlayer handles it's own threading, you don't need to create one. [AVAudioPlayer play] returns after it started playing, not after it is done playing.
And don't forget to release your AVAudioPlayer when you no longer need it, for example if you only want to play a sound onces, implemement the audioPlayerDidFinishPlaying:successfully: delegate and release it in there.
How are you playing the sound? If I was to make a guess it would be that each time the sound is played the OS is actually loading it from disk as well as playing it.
Update:
Ok, you really don't need to be creating a new thread to play a sound. This alone could cause a stutter in a game and is also redundant - The AVAudioPlayer play method is asynchronous - it returns immediately and not when the sound ends.
I had the same problem with slowdown. To solve it, I first play and pause the sound when it first loads at volume 0 - this works better than prepareToPlay which still seems to result in slowdown:
player.volume = 0.0;
[player play];
[player pause];
player.volume = 1.0;
When it comes time to play a sound I just [player play];. Then every update cycle I loop through all my active sounds and catch ones that are about to end and rewind them instead of letting them expire - this avoids the overhead and slowdown of starting up the sound from scratch. The example here stops the sounds 1/15th of a second from the end of the sound:
for ({each player in active sounds})
{
if ((player.duration - player.currentTime) <= (1.0/15.0))
{
[player pause];
player.currentTime = 0.0;
}
}
Now it's ready to go for the next play. Seems to work fine!
Update: Turns out I was still getting some pauses the very first time the sound was played. I think playing it at zero volume wasn't actually doing anything, but I changed it to play at 0.0001 volume and then pause - it's inaudible but seems to do the job of prepping the sound.
Had the same problem at first. Per documentation you need to call "prepareToPlay" every time a sound has finished playing. Adopting the AVAudioPlayerDelegate protocol and adding the following method will do this.
-(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
[player prepareToPlay];
}
(Using an answer rather than a comment for length and so I can show code):
My sound playing method is as follows:
- (void)playSoundThreaded:(id)soundPlayer
{
if(soundPlayer == nil)
return;
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
[(AVAudioPlayer*)soundPlayer play];
[pool release];
}
- (void)playSound:(AVAudioPlayer*)player
{
if(player == nil)
return;
[NSThread detachNewThreadSelector:#selector(playSoundThreaded:)
toTarget:self withObject:(id)player];
}
And the sound is loaded up as follows:
fxPlayer = [[AVAudioPlayer alloc] initWithData:
[NSData dataWithContentsOfFile:
[[NSBundle mainBundle] pathForResource:#"voicehiya" ofType:#"caf"]] error:NULL];
We've had some inkling that the sound is being reloaded from disk every time...but have no idea as to why that is or how to prevent it.
I think the thread is over complicating your player. Try this for a go:
/* setup the sound player */
AVAudioPlayer *player1=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:audioFilePath] error:NULL];
player1.numberOfLoops = 0;
player1.volume=1.0f;
[player1 prepareToPlay];
and then playSound becomes
[player play];
And don't forget to have the AudioSession category set correctly too.
Why not just use AudioServicesPlaySystemSound? This is well suited to sound effects.
I use it in my game (vConqr) which is also based on a UIScrollView, with numerous other views (so all having their own CALayer), and it doesn't significantly impact performance.
I've been investigating this for a few days now thanks to a project I'm on at work. I added some home-rolled profiling to my code and found that the calls to play sounds were causing frame rate issues in my OpenGL game. I've got a few recommendations for you based on what I've found:
Use an AVAudioPlayer playing an mp3 for your background music.
Use OpenAL for your sound effects.
For sound effects, use the audio converter command line tool from apple to get your sounds to .caf format. This is an uncompressed format that doesn't require the CPU to decompress your sound to memory before sending it to the sound card. It can go directly, saving you time. Instructions on using the tool can be found HERE. (scroll to the very bottom of the page)
Use the lowest bit depths that still sound good. You don't really need 128 kbps - you can probably get away with 20 for a lot of things. Lower bit rate = less processing = faster sound.
I'll let you know if I find anything else that's useful! Good luck!