AVPlayer与iOS中的UISlider同步

Question

Working on an app in iOS , I am playing a video using AVPlayer and i am synchronising the slider with the playerItem current duration using:

//synchronizing the current time label and slider with the player.
[self.player addPeriodicTimeObserverForInterval:CMTimeMake(1, 100) queue:dispatch_get_main_queue() usingBlock:^(CMTime time)

{
    CMTime endTime = CMTimeConvertScale (self.player.currentItem.asset.duration, self.player.currentTime.timescale, kCMTimeRoundingMethod_RoundHalfAwayFromZero);
    if (CMTimeCompare(endTime, kCMTimeZero) != 0) {
        double normalizedTime = (double) self.player.currentTime.value / (double) endTime.value;
        self.slider.value = normalizedTime;
    }
    Float64 currentSeconds = CMTimeGetSeconds(self.player.currentTime);
    int mins = currentSeconds/60.0;
    int secs = fmodf(currentSeconds, 60.0);
    NSString *minsString = mins < 10 ? [NSString stringWithFormat:@"0%d", mins] : [NSString stringWithFormat:@"%d", mins];
    NSString *secsString = secs < 10 ? [NSString stringWithFormat:@"0%d", secs] : [NSString stringWithFormat:@"%d", secs];
    self.currentTimeLabel.text = [NSString stringWithFormat:@"%@:%@", minsString, secsString];
}];

The problem is that i am playing the video in Modal view, when I press the button to dismiss the view controller, the view controller dismisses but the video keep on playing in the background(as the audio of the asset can be heard). How can i solve that? I am sure that it has to do with the queue I am using, but i have tried both the main queue and the concurrent queue, but every time, results are same.

Answer 1

I think you need to stop AVAssetReader by calling cancelReading method on it.

Doc:

cancelReading

Cancels any background work and prevents the receiver's outputs from reading more samples.

• (void)cancelReading Discussion If you want to stop reading samples from the receiver before reaching the end of its time range, you should call this method to stop any background read ahead operations that the may have been in progress.

Also you should use removeTimeObserver method of AVPlayer when you dismiss modal view.

There is also pause method of AVPlayer if you don't have AVAssetReader .