Develop Reference

Python Kivy: Play sound multiple times at once

I am using Python Kivy for an Android Game. I want to play a sound on an event
sound = SoundLoader.load("sound.wav")
def onEvent():
sound.play()
, and It works. But now the problem: Of course an event can, and in my case will happen again before the sound is done playing from the last event. And as the sounds are based on a play/pause idea I am getting a problem playing multiple sounds of the same object at once. That can be solved like this for first:
onEvent():
SoundLoader.load("sound.wav").play()
As this creates a new object all the time, and so is able to play it the same time another event plays the sound. But the problem using this method is quite obvious, because the sound must be loaded everytime the event occurs, and so causes a delay until it's played.
Is there a more useful way to do this?
{ if you don't understand what I am talking about, or just don't see the problem, feel free to ask }

You can workaround this by loading multiple instances of the sound.
For instance
sounds = [SoundLoader.load("sound.wav") for _ in range(10)]
index = 0
and then
def play():
sounds[index].play()
index = (index + 1) % len(sounds)
The more sounds you load, the more instances you can have playing at the same time (in this example 10).

switching from Media Player to Media Player force close

hi ive been working on my app and have found a hurdle in an activity i just cant seem to overcome. the activity is essentially a large novelty piano with 8 keys that play sounds there are 6 buttons along the side that change the picture of the notes and the notes themselves, this i accomplished :-) now i would like to add a background song to each different set of notes (instruments) only when i do the app crashes i have set the mediaplayer at the top (globally?) using MediaPlayer mp; MediaPlayer mp2; etc and im using this in my code to check if any music is playing, stop it, release it, and then play the piece i want,
if(mp!=null&&mp.isPlaying()){
mp.stop();
mp.release();
}
if(mp2!=null&&mp2.isPlaying()){
mp2.stop();
mp2.release();
}
if(mp3!=null&&mp3.isPlaying()){
mp3.stop();
mp3.release();
}
mp3 = MediaPlayer.create(MusicActivity.this, R.raw.snaps);
mp3.setLooping(true);
mp3.start();
this again works but going from one to another and then back crashes the app. is there something else i should be doing? or is just an out of memory error?
EDIT--
Thanks to ranjk89 for his help
changed to soundpools but they wont stop ranjk89 suggests referring to the stream id and not the sound id looking for a little more clarification if possible i have
farmback =0;
drumback =0;
at the top then its loaded in oncreate using
drumback = sp.load(this, R.raw.snaps,1);
farmback = sp.load(this, R.raw.oldmacdonaldbeta,1);
and then way down, in the same method i change the button icons, not the same method i change all my other sounds for my notes i call
sp.stop(drumback);
sp.play(farmback, 1, 1, 0, -1, 1);
in one and
sp.stop(farmback);
sp.play(drumback, 1, 1, 0, -1, 1);
in another but there are 6 different instruments in total that all need a different backing track which should stop when the instrument is changed and play the one associated to it so something like
if (sp !=null && sp.isplaying()){
sp.stop();
sp.play(dumback);
}
but obviously this is not possible any help appreciated

My Initial reaction is, you shouldn't be using multiple MediaPlayer at all in the first place.
I would suggest you to use SoundPool as you can load all the media(audio) initially, once they are all loaded you can play them at will. Plus you won't have multiple players which would downsize the complexity of your code.
But if you do want to use Media player,
See this. But be aware that once you release you will not be able to reuse that instance of MediaPlayer. Even if you are using multiple MediaPlayers, do not call release on them unless you are sure you don't want to use them any more. Use stop()/prepare() combination.
For application doing too much work on the Main Thread,
If you either use a SoundPool or only one MediaPlayer and still bump in to the same issue, Use AsyncTask. Android dev site has a very good tutorial on this

Serious problems playing sounds on my app with MediaPlayer

My game play short sounds pressing buttons depending on sharedpreferences following this lines
SharedPreferences sound = getSharedPreferences("settings",
Context.MODE_PRIVATE);
if (sound.getInt("SOUND", 10) == -1 || sound.getInt("SOUND", 10) == 10){
mp = MediaPlayer.create(getApplicationContext(), R.raw.selection);
mp.start();
}
Normally, the sounds are played too frequently in the game, and this works fine but, at some point random errors occurs.
For example, start other activities, the sounds don't play and, in some random button press, start to play again.
Those problems began to happen after I implemented this lines in the code.
I don't know the relation with those actions here, for this I need your help.
Is something wrong here or can I implement some alternative way to play sounds?
Thanks

How to play sounds at accurate periods of time across different devices in Android

I'm developing a game in Android and I came across a very annoying, hard-to-find bug. The issue is that when you are using SoundPool to play your sounds, you can actually loop whatever sound you are playing. In this case, the issue is the "running steps" sound; this sound gets executed quite fast and continually (around every 400ms) when the main character is running.
Now when playing the sound on a regular (not so powerful) device e.g. Samsung SII, the sound is played every 500ms - however, if I run the very same code on another device (let's say, Samsung SIV, Samsung SIII), the sound plays twice or even three times faster.
It seems like the more powerful the device hardware specs are, the faster it plays. On some devices, it plays so fast that you almost hear one solid continuous sound. I've been looking for techniques to set a specific ratio on the time period between sound plays, but it doesn't work properly and the issue remains. Does anyone know how to fix it, either using SoundPool, MediaPlayer, or any other sound-controlling API on Android?

You could use an AudioTrack to play a continuous stream of PCM data, since you would pass a stream you could be sure about the interval between sounds. the downside could be a little delay when first starting the sound but it depends on the minimum buffer size, and it depends, I think, on android version and device. On my galaxy s2 android 4.1 it was about 20ms.if you think this could be an option I can post some code

The problem with just looping or using a regular interval for something like footsteps is that you have a possible decoupling of sound and visuals. If your sound gets delays or sped up, or your visuals get delayed or sped up, you would have to adjust for that delay dynamically and automatically. You already have that issue right here
A better solution would be to place a trigger on the exact event which should trigger the sound (in this case, the foot being placed down), which then plays the sound. This also means that if you have multiple sources of the sound (like multiple footsteps), you don't have to manually start the sound with the right interval.

I can't seem to replicate the issue on Galaxy Nexus and Nexus S, does that mean I fixed it? Or maybe you could show what you're doing differently from this:
SoundPool soundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 100);
Integer sound1 = soundPool.load(this, R.raw.file1, 1);
Integer sound2 = soundPool.load(this, R.raw.file2, 1);
playSound(sound1);
public void playSound(int sound) {
AudioManager mgr = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
float volume = mgr.getStreamVolume(AudioManager.STREAM_MUSIC)
/ mgr.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
soundPool.play(sound, volume, volume, 1, -1, 1.0f);
}

If the problem is that you want to control the interval between the discrete sounds, The easiest way to do this is with a handler.
Basically you start a sound playing which is an asynchronous process. Then you use a handler to schedule a message to play the next sound sometime in the future. It will take some trial and error to get it right, but you will be guaranteed that the sound will start at the same interval after the previous sound on every device.
Here is some code to illustrate what I am talking about.
Here is a handler implementation you could use:
handler = new Handler() {
/* (non-Javadoc)
* #see android.os.Handler#handleMessage(android.os.Message)
*/
#Override
public void handleMessage(Message msg) {
if (msg.what == NEXT_ITEM_MSG) {
playNextSound();
}
else if (msg.what == SEQUENCE_COMPLETE_MSG) {
// notify a listener
listener.onSoundComplete()
}
}
};
Then you could write playNextSound like this:
private void playNextSound() {
if (mRunning) {
// Get the first item
SoundSequenceItem item = currentSequence.getNextSequenceItem();
if (item == null) {
Message msg = handler.obtainMessage(SEQUENCE_COMPLETE_MSG);
handler.sendMessage(msg);
return;
}
// Play the sound
int iSoundResId = item.getSoundResId();
if (iSoundResId != -1) {
player.playSoundNow(soundResId);
}
// schedule a message to advance to next item after duration
Message msg = handler.obtainMessage(NEXT_ITEM_MSG);
handler.sendMessageDelayed(msg, item.getDuration());
}
}
and your SoundSequenceItem could just be a simple class that has a sound file resource id and a duration. If you want to keep playing the sound while the character is moving you could do something like this:
public void onSoundComplete() {
if (character.isRunning()) {
currentSequence.addSequenceItem(new SoundSequenceItem(R.id.footsteps,500);
playNextSound();
}
}
Or you could modify playNextSound to continually play the same sound. Mine is written this way to be able to play different sounds in sequence.

I have had a lot of problems developing apps which used sounds and stuff like that. I would not suggest you to use SoundPool since it is bug-affected, and also be aware that looping sounds with SoundPool won't work on devices which are 4.3 and higher, see this open issue, at AOSP - Issue tracker.
I think that the solution is to go native and use OpenSL ES o similar libraries.

How to stop all sounds in SoundPool?

I am using SoundPool to play sfx sounds in a game on Android. In most cases it works perfectly, except sometimes I need to stop all sounds at once not pause (doesn't matter if they are set to loop or not).
I can't figure out how to stop a sound from playing without knowing the StreamID of that sound. What I know:
soundpool.load(...some sound...) returns a soundID
soundpool.play(soundID) plays the sound and returns a streamID
soundpool.stop(streamID) stops the sound
My question is, how can I stop a sound without knowing the streamID ? I tried tracking all streamIDs in a list, but sometimes there are so many short streams playing at once, that it won't work. And I can't find any method in SoundPoolto get the active streamIDs. Does anyone know how to stop all sounds?
Any hint is appreciated! thanks

I'd recommend using autoPause() and autoResume() to pause and restart your sounds. This function is part of the soundpool:
http://developer.android.com/reference/android/media/SoundPool.html#autoPause()

What about using .release() ? Accourding to the documentation:
Release the SoundPool resources. Release all memory and native resources used by the SoundPool object. The SoundPool can no longer be used and the reference should be set to null.
I think it also stops everything. (Actually it was causing a bug at one of my apps, that's why I say it)
However, I believe that if you want to play any sounds later, you may have to load them again.

SoundPool doesn't have a method to retrieve the streamID from the index of the stream, like it should. So even when you know the maximum number of streams, you can't just iterate through like the following:
for(int index=0;index<MAXSTREAMS;index++){
int streamid = SoundPool.getStreamID(index);//getStreamID action doesn't exist :(
soundpool.stop(streamid);
}
As you mentioned, the coder has to manage this himself with a list. I implement the declaration as follows:
List<Integer> streams = new ArrayList<Integer>();
You can add and remove soundIDs to this list as you play and stop sounds as follows:
streams.add(batattack_soundID);
streams.remove(Integer.valueOf(batattack_soundID));//NOT streams.remove(batattack_soundID);
Be sure to use Integer.valueOf() or .remove() will interpret your parameter as an index position, likely giving you an IndexOutOfBoundsException.
To clean everything up you can code as follows:
for (Integer stream : streams) {
soundPool.stop(stream);
}
streams.clear();