尝试修复 AVAudioPlayer 在其初始使用时的滞后 [英] Trying to fix AVAudioPlayer lag on its initial use

问题描述

此问题已出现在 SO 上的其他几个问题中:

This issue has shown up in several other question here on SO:

第一次慢启动 AVAudioPlayer播放声音

使用 AVAudioPlayer 延迟播放声音

我已尝试实施建议的修复，但没有一个解决我的问题.我的应用程序向用户展示了要触摸的对象网格，当触摸对象时会播放声音.这很好用，只是在初次触摸时会有约 2 秒的延迟.

I've tried implementing the fixes suggested but none of them are solving my problem. My application presents the user with a grid of objects to touch, when an object is touched a sound is played. This works great except on the initial touch there is a delay of ~2 seconds.

为了解决这个问题，我用一个虚拟的 aiff 文件初始化我的音频播放器:

To get around this I initialize my audio player with a dummy aiff file:

- (void)viewDidLoad{
    NSString *soundFile = [Card loadCardSoundPath:@"dummy"];

    AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:
                             [NSURL fileURLWithPath:soundFile] error:nil];
    self.audioPlayer = player;
    [audioPlayer setDelegate:self];
    [audioPlayer prepareToPlay];
//    [audioPlayer play];
    [player release];
...
[super viewDidLoad]; 
}

然后当一个物体被触摸时，我会调用:

Then when an object is touched I call:

NSString *soundFile = [Card loadCardSoundPath:name];

if (soundFile != nil){

            AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:
                                     [NSURL fileURLWithPath:soundFile] error:nil];
            self.audioPlayer = player;
            [self.audioPlayer setDelegate:self];
            [self.audioPlayer prepareToPlay];
            [self.audioPlayer play];
            [player release]; 
}

我观察到的行为是这样的:如果我创建一个虚拟音频播放器并调用 prepareToPlay 但不播放，我会在单击第一个对象时观察到音频延迟.但是，如果我在虚拟音频播放器上调用 play，那么我不会得到初始对象的延迟，但视图加载会延迟 2 秒.

The behavior i'm observing is this: I observe the audio delay when I click the first object if I create a dummy audio player and call prepareToPlay but not play. However if I call play on the dummy audio player then I don't get the delay on the initial object but the view load gets delayed by 2 seconds.

有没有办法解决这个问题?我是否应该在加载时简单地创建一个 AVAudioPlayers 的 NSArray 并告诉他们准备播放，然后在单击对象时调用 play?

Is there a way to get around this? Should I simply create an NSArray of AVAudioPlayers on load and tell them all to prepare to play, and then just call play when the object is clicked?

推荐答案

有时通过使用 peformSelector:withObject:afterDelay:代码>.例如:

Sometimes it can help to let viewDidLoad return by spooling off initialization like that using peformSelector:withObject:afterDelay:. For example:

- (void)viewDidLoad{
    // initialization ...
    [super viewDidLoad]; 
    [self performSelector:@selector(primeAudioPlayer) withObject:nil afterDelay:0.1];
}

-(void)primeAudioPlayer {
    NSString *soundFile = [Card loadCardSoundPath:@"dummy"];

    AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:
                             [NSURL fileURLWithPath:soundFile] error:nil];
    [audioPlayer prepareToPlay];
    [player release];
}

这篇关于尝试修复 AVAudioPlayer 在其初始使用时的滞后的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！