iphone - 完成用 finch 播放音频回调

Question

finch 有没有完成播放回调？类似于 - avaudioplayer 中的 audioPlayerDidFinishPlaying？浏览代码我找不到任何引用它的东西。

Answer 1

Finch 中没有这样的回调，因为 OpenAL 不支持。（或者至少我上次看时它不支持它。）你可以像这样伪造它：

- (void) playSoundWithCallback {
    [someSound play];
    [someDelegate performSelector:@selector(soundDidFinishPlaying:)
        withObject:someSound afterDelay:someSound.duration];
}

我没有尝试过，但它是一个简单的代码，它应该可以正常工作。好吧……至少在你开始弄乱音高和音速之前:)

Answer 2

@zoul: I know this is a vey late reply. But I noticed that the answer is not correct. What if I pause the sound or if there is an interruption from system. In such case, you will receive a callback even if the sound is not completed yet. Please read paragraph "4.3.6. Managing Source Execution" from openAL specs for correct handling.

Answer 3

如果您不关心中断，这是一个带有音高修复的技巧。

当音高不是 1.0 时，OpenAL 会更改播放声音的播放长度。（似乎无法从 OpenAL 查询这个新长度，因为 AL 参数返回与以前相同的值）

间距范围从 0.5 到 2.0f。因此，如果我们假设 0.5 处的音高正好是两倍长，而 2.0 处的音高正好是一半长，我们应该能够将音高用作倍数：

- (void) playSoundWithCallback {
    [someSound play]; 
    [someDelegate performSelector:@selector(soundDidFinishPlaying:) 
        withObject:someSound afterDelay: someSound.duration * (1.0/someSound.pitch) ]; 
}