iPhone应用程序中不同声音之间的延迟

Question

我正在尝试制作一个带有一些按钮的小型iPhone应用程序来播放WAV声音.我的按钮工作,但我有一个小延迟(~0.5秒).

这是我的.m文件:

#import "buttonSoundViewController.h"

@implementation buttonSoundViewController
//@synthesize player;

-(IBAction) playSoundA:(id)sender{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"a" ofType:@"wav"];
    AVAudioPlayer* theAudio = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];
    theAudio.delegate = self;
    [theAudio play];
}

-(IBAction) playSoundB:(id)sender{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"b" ofType:@"wav"];
    AVAudioPlayer* theAudio = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];
    theAudio.delegate = self;
    [theAudio play];
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag {
    [player release];
}

-(void)audioPlayerDecodeErrorDidOccur:(AVAudioPlayer *)player error:(NSError *)error {
}

-(void)audioPlayerBeginInterruption:(AVAudioPlayer *)player {
}

-(void)audioPlayerEndInterruption:(AVAudioPlayer *)player {
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
}

- (void)viewDidUnload {
}

- (void)dealloc {
    [audioPlayer release];
    [super dealloc];
}   

@end

如何在播放不同声音之间避免这种延迟？

Answer 1

对于小声音(少于30秒),使用AudioServices确实快得多.所需的代码也不是很长(但它需要一些好的旧C).

#import <AudioToolbox/AudioServices.h>

SystemSoundID soundID = 0;
NSString* str =  [[NSBundle mainBundle] pathForResource:fileName ofType:nil];
CFURLRef soundFileURL = (CFURLRef)[NSURL URLWithString:str ];
OSStatus errorCode = AudioServicesCreateSystemSoundID(soundFileURL, &soundID);
if (errorCode != 0) {
    // Handle failure here
}
else
    AudioServicesPlaySystemSound(soundID);

您还可以使用以下终端命令优化声音(减小其大小):

afconvert mysound.caf mysoundcompressed.caf -d ima4 -f caff