AVSpeechSynthesizer postUtteranceDelay计时问题

Question

下面的代码获取一个方向列表，并使用AVSpeechSynthesizer读出它们。一旦完成，用户将能够选择可变的时间量，应用程序将读取指令以适应时间跨度。

问题是，当我按下播放按钮时，方向之间的延迟比正常情况下要长得多。而不是我硬编码的两分钟，它需要超过三分钟。我已经记录了我所有postUtteranceDelays的值，它们正确地累加起来。这也不是由于处理时间的原因，因为当postUtteranceDelay设置为0时，方向之间没有停顿。我不知道是怎么回事。

- (IBAction)play:(UIButton *)sender {
[sender setTitle:@"Showering" forState:UIControlStateNormal];
Shower *shower = [[SpecificShower alloc] init];

NSUInteger totalRatio = [shower calculateTotalRatio:shower];
NSNumber *offset = @18.0; // estimated time to speak instructions combined
NSNumber *seconds = @120.0; // hard coded but just for testing
int totalSeconds = seconds.intValue - offset.intValue;

self.synthesizer = [[AVSpeechSynthesizer alloc] init];

for (NSDictionary* direction in shower.directions) {

    AVSpeechUtterance *aDirection = [[AVSpeechUtterance alloc] initWithString:direction[@"text"]];
    NSNumber *directionLength = direction[@"length"];
    aDirection.rate = .3;
    aDirection.preUtteranceDelay = 0;
    // totalRatio is calculated by adding all the lengths together 
    // then the individual direction length is divided by totalRatio
    // and that fraction is multiplied by total number of seconds
    // to come up with the postUtteranceDelay for each direction
    aDirection.postUtteranceDelay = totalSeconds * [directionLength floatValue]/totalRatio;
    NSLog(@"%f", aDirection.postUtteranceDelay);
    [self.synthesizer speakUtterance:aDirection];
}

}

Answer 1

你并不孤单。这似乎是here上的一个变通方法中提到的一个错误。

还有here和here的雷达。

让我们希望这个问题能很快得到解决。