iphone - AVAudioPlayer currentTime issue

Question

I'm trying to use the AVAudioPlayer with a slider in order to seek into a track (nothing complicated).

But I have a weird behavior... for some value of currentTime (between 0 and trackDuration), the player stop playing the track, and goes into audioPlayerDidFinishPlaying:successfully: with successfully to NO. And it did not go into audioPlayerDecodeErrorDidOccur:error:

It's like it can't read the time I'm giving to it.

For exemple the duration of the track is: 295.784424 seconds I set the currentTime to 55.0s (ie: 54.963878 or 54.963900 or 54.987755, etc... when printed as %f). The "crashes" always happen when the currentTime is 54.987755... and I really don't understand why...

So if you have any idea... ^^

Answer 1

I also struggled to get audio skipping working properly with 'AVAudioPlayer setCurrentTime:`

After alot of experimentation i've found a sequence that works reliably on the simulator and the device: (tested on OS3.1+)

// Skips to an audio position (in seconds) of the current file on the [AVAudioPlayer* audioPlayer] class instance
// This works correctly for a playing and paused audioPlayer
//
- (void) skipToSeconds:(float)position
{
    @synchronized(self) 
    {
        // Negative values skip to start of file
        if ( position<0.0f )
            position = 0.0f;

        // Rounds down to remove sub-second precision
        position = (int)position;

        // Prevent skipping past end of file
        if ( position>=(int)audioPlayer.duration )
        {
            NSLog( @"Audio: IGNORING skip to <%.02f> (past EOF) of <%.02f> seconds", position, audioPlayer.duration );
            return;
        }

        // See if playback is active prior to skipping
        BOOL skipWhilePlaying = audioPlayer.playing;

        // Perform skip
        NSLog( @"Audio: skip to <%.02f> of <%.02f> seconds", position, audioPlayer.duration );

        // NOTE: This stop,set,prepare,(play) sequence produces reliable results on the simulator and device.
        [audioPlayer stop];
        [audioPlayer setCurrentTime:position];
        [audioPlayer prepareToPlay];

        // Resume playback if it was active prior to skipping
        if ( skipWhilePlaying )
            [audioPlayer play];
    }
}