I'm generating tones on iPhone using AudioUnits based on Matt Gallagher's classic example. In order to avoid the chirps and clicks at the beginning/end, I'm fading the amplitude in/out in the RenderTone callback. I'd like to destroy the ToneUnit at the end of the fade out, that is, after the amplitude reaches zero. The only way I can think to do this is to call an instance method from within the callback:
if (PlayerState == FADING_OUT) {
amplitude -= stepsize;
if (amplitude <= 0) {
amplitude = 0;
PlayerState = OFF;
[viewController destroyToneUnit];
}
}
Unfortunately this is more challenging that I had thought. For one thing, I still get the click at the end that the fadeout was supposed to eliminate. For another, I get this log notice:
<AURemoteIO::IOThread> Someone is deleting an AudioConverter while it is in use.
What does this message mean and why am I getting it?
How should I kill the ToneUnit? I suspect that the click occurs because RenderTone and destroyToneUnit run on different threads. How can I get these synchronized?
In case it's helpful, here's my destroyToneUnit instance method:
- (void) destroyToneUnit {
AudioOutputUnitStop(toneUnit);
AudioUnitUninitialize(toneUnit);
AudioComponentInstanceDispose(toneUnit);
toneUnit = nil;
}
If I NSLog messages right before and right after AudioUnitUninitialize(toneUnit);, the notice appears between them.
I also ran into the same issue. When I called the destroyToneUnit from the main thread, the warning went away.
[viewController performSelectorOnMainThread:#selector(destroyToneUnit) withObject:nil waitUntilDone:NO];
Related
Ive got the following code to check for agent collision.
I want to fire a MIDI message only once when they start colliding.
Ive got this so far.
void draw(){
//Loop through people, and check collision, then play note, if intersecting
for(int i=0;i<people.size();i++){
Person p = people.get(i);
p.collide(people,collisions);
p.triggerMidi();
p.run();
}
}
public void collide(ArrayList<Person> people, ArrayList<Person> connections) {
for(Person other : people) {
if (other != this) {
if (this.collide(other)) {
this.isIntersecting=true;
//connections.add(other); // when a collision is found, add it to a list for later use.
}
}
}
}
void triggerMidi(){
if(!hasPlayed && this.isIntersecting==true){
MIDI.sendNoteOn(channel, agentNote, 127);
delay(200);
MIDI.sendNoteOff(channel,agentNote, 127);
hasPlayed=true;
}
}
This works to play the sound only once at the start of collision.
But how do I get it to play again at the start of another collision.
Obviously I have to set hasPlayed back to false.
But where?
When I set it to false in the collide loop, the sound play a million times.
Any ideas?
First off, you probably shouldn't have a call to delay() from your drawing thread. That will cause your sketch to become laggy and unresponsive. Instead, you might want to put your sound playing on a different thread.
Then, to answer your original question- do you know how long the note plays for? If so, just record the time that the note starts, and then use that time to check the elapsed time. The millis() function might come in handy for that. When the elapsed time is greater than the duration of the note, then you can set hasPlayed back to false.
While using MPMoviePlayerController is there any way to find how much Percentage of data finished while buffering the video?
My aim is to show the progress bar that showing how much percentage is loaded and show its numeric count of percentage.
Thanks in advance.
Have you checked out the Apple documentation for the MPMoviePlayerController ?
http://developer.apple.com/library/ios/#documentation/mediaplayer/reference/MPMoviePlayerController_Class/Reference/Reference.html
Here you can find two properties that might help you. duration and playableDuration, it's not an exact fit, but pretty close. One thing you will need to implement yourself is a way to intelligently query these properties, for example maybe you might want to use an NSTimer and fetch the info from your MPMovePlayerController instance every 0.5 seconds.
For example assume you have a property called myPlayer of type MPMoviePlayerController, you will initiate it in your init method of the view controller etc...
Then followed by this:
self.checkStatusTimer = [NSTimer timerWithTimeInterval:0.5
target:self
selector:#selector(updateProgressUI)
userInfo:nil
repeats:YES];
And a method like this to update the UI:
- (void)updateProgressUI{
if(self.myPlayer.duration == self.myPlayer.playableDuration){
// all done
[self.checkStatusTimer invalidate];
}
int percentage = roundf( (myPlayer.playableDuration / myPlayer.duration)*100 );
self.progressLabel.text = [NSString stringWithFormat:#"%d%%", percentage];
}
Note the double percentage sign in our -stringWithFormat, this is another format specifier to resolve to a % sign. For more on Format specifiers see here.
I'm trying to make a simple game and I am currently trying to make an arrow shoot out.
So far I have two functions,
-(void)ccTouchesBegan
Touches began does some math and gets a vector from the initial shooting point of arrow and the thumbpress, then passes this data into another function:
-(void)shatArrow:(CGPoint)cl:(CGPoint)nv{
}
What I want is for the shatArrow function to call a ccTime function that runs solely for the purpose of making the arrow move, and once the arrow is done with it's projection, the ccTime function will stop, and can be called again later when needed.
How would I go about this?
Schedule the update selector (ie in the init method of your class):
[self scheduleUpdate];
Then implement the update method:
-(void) update:(ccTime)delta
{
if (isArrowMoving)
{
// arrow move code here
if (arrow movement should end)
{
isArrowMoving = NO;
}
}
}
You can keep the update method running, unless you have hundreds of arrows it won't affect performance.
-(void) shootArrow:(CGPoint)cl:(CGPoint)nv
{
isArrowMoving = YES;
// other arrow movement init code here
}
Btw, it's "shoot, shot, shot" and not "shoot, shot, shat" or something like that. (I suppose you didn't ask for a #LinguisticsOverflow answer) ;)
I have a fairly simple looped operation that checks for obvious errors and likely problems in a data structure. I won't go into detail about it. What I want to be able to do is pause the execution of this loop whenever an error is encountered so that I can ask the user what they want to do about that error, before continuing to check the remaining data.
Can anyone give any ideas about how best to do that?
-Ash
This will stop your loop for 0.25 seconds, but it's not what you are looking to do. You need to reformulate your question first.
CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.25, false);
Don't do long operations inside a loop in the UI run loop. It presents a non-responsive UI to the user; and the OS may kill the app if it locks up for too long.
Break the loop into short callbacks (make the inside of each loop iteration a method), and exit each callback after maybe a fraction of a seconds worth of inner loop operations.
Or execute the loop as a task in a background thread, and use locks to stop the loop while waiting for messages from the foreground UI run loop about what to do for some loop state.
Seems like UIAlertView is what you are looking for:
UIAlertView Class Reference
UIAlertView is asynch, so it won't pause the loop.
There are cleverer ways to write your loop, e.g. using blocks or completion handlers, but I'd suggest the EASIEST way is simply convert your code from:
-(void) method
{
...
for( int i=0; i<10; i++)
{
check_loop_item(i);
}
}
to:
int iCurrent, iEnd;
-(void) method
{
...
iCurrent = 0;
iEnd = 10;
[self doLoop];
}
-(void) doLoop
{
if( iCurrent >= iEnd )
return;
check_loop_item(iCurrent);
...
if( error )
{
// Popup a UIAlertView
}
else
{
iCurrent++;
[self doLoop];
}
...and in the callback method from UIAlertView, do:
-(void) callbackFromUIAlertView
{
iCurrent++;
[self doLoop];
}
...i.e. a loop that runs once at a time, and lets you arbitrarily stop / pause / resume it.
I used an AVAudioPlayer object to control playing multiple music files. I also created an UISlider to control seeking file. But i have a problem when seek the pointer. After seeking, AVAudioPlayer update time correct then jump into "audioPlayerDidFinishPlaying" function unexpected.
Here is the code that i used :
-(void)timeChange
{
_player.currentTime = _timeControl.value;
[self updateCurrentTimeForPlayer];
}
-(void)updateCurrentTimeForPlayer
{
if(_isNeedUpdate == NO) return;
_timeControl.maximumValue = _player.duration;
}
A long shot, but maybe the audio format doesn't support seeking?
Why the call to updateCurrentTimeForPlayer? Where is _isNeedUpdate set? (Why all the underscores?)
Can you add some debug NSLogs to find out what's going on?