Question

我有一个使用AVQueuePlayer播放音乐的TvOS应用程序（歌曲存储在远程服务器上）。通常，歌曲连续播放几个小时。有时候，它会在很短的时间内滞后并继续玩。但有些时候，它只是持续滞后。当发生这种情况时，重新启动应用程序或重新启动Apple TV无法解决问题。

我的应用程序没有滞后（只播放播放器），Apple TV上的互联网连接完美（使用SpeedTest检查）并且远程服务器正常响应（我的电脑没有问题缓冲文件和ping非常快。）

因此，我已在rate的{{1}}属性上添加了观察者，以检查其AVQueuePlayer的某些属性，以获取有关该问题的更多信息。

currentItem

这会产生以下日志：

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if([keyPath isEqualToString:@"rate"] && object == queuePlayer) {
        NSLog(@"rate: %@", @(queuePlayer.rate));
        NSLog(@"duration: %@", @(CMTimeGetSeconds(queuePlayer.currentItem.duration)));
        NSLog(@"time: %@", @(CMTimeGetSeconds(queuePlayer.currentItem.currentTime)));
        NSLog(@"playbackLikelyToKeepUp: %@", @(queuePlayer.currentItem.playbackLikelyToKeepUp));
        NSLog(@"playbackBufferEmpty: %@", @(queuePlayer.currentItem.playbackBufferEmpty));
        NSLog(@"playbackBufferFull: %@", @(queuePlayer.currentItem.playbackBufferFull));
        NSLog(@"bufferSize: %@", @([self bufferSize]));
        double currentTime = CMTimeGetSeconds(queuePlayer.currentItem.currentTime);
        if(queuePlayer.rate == 0 && currentTime != 0 && currentTime < CMTimeGetSeconds(queuePlayer.currentItem.duration) - 0.1) {
            [queuePlayer prerollAtRate:1 completionHandler:^(BOOL finished) {
                NSLog(@"Finished prerolling");
                [queuePlayer play];
            }];
        }
    }
}

- (NSTimeInterval) bufferSize {
    NSArray *loadedTimeRanges = [[queuePlayer currentItem] loadedTimeRanges];
    CMTimeRange timeRange = [[loadedTimeRanges objectAtIndex:0] CMTimeRangeValue];
    Float64 startSeconds = CMTimeGetSeconds(timeRange.start);
    Float64 durationSeconds = CMTimeGetSeconds(timeRange.duration);
    NSTimeInterval result = startSeconds + durationSeconds;
    return result;
}

正如您所看到的，2016-04-13 15:59:49.947 Virtual Juke[517:427012] rate: 0 2016-04-13 15:59:49.949 Virtual Juke[517:427012] duration: 203.5461224489796 2016-04-13 15:59:49.949 Virtual Juke[517:427012] time: 29.325428829 2016-04-13 15:59:49.950 Virtual Juke[517:427012] playbackLikelyToKeepUp: 1 2016-04-13 15:59:49.950 Virtual Juke[517:427012] playbackBufferEmpty: 1 2016-04-13 15:59:49.950 Virtual Juke[517:427012] playbackBufferFull: 0 2016-04-13 15:59:49.953 Virtual Juke[517:427012] bufferSize: 203.52 2016-04-13 15:59:49.958 Virtual Juke[517:427012] Finished prerolling 2016-04-13 15:59:49.959 Virtual Juke[517:427012] rate: 1 2016-04-13 15:59:50.733 Virtual Juke[517:427012] duration: 203.5461224489796 2016-04-13 15:59:50.733 Virtual Juke[517:427012] time: 28.566945193 2016-04-13 15:59:50.734 Virtual Juke[517:427012] playbackLikelyToKeepUp: 1 2016-04-13 15:59:50.734 Virtual Juke[517:427012] playbackBufferEmpty: 1 2016-04-13 15:59:50.734 Virtual Juke[517:427012] playbackBufferFull: 0 2016-04-13 15:59:50.737 Virtual Juke[517:427012] bufferSize: 203.52有一些矛盾的属性值。它说它的缓冲区在暂停时是空的，当它恢复时，它已经准备好了...当我计算缓冲区时，看起来它已经缓冲了整首歌。

究竟是什么问题，为什么会发生？

TvOS AVQueuePlayer缓冲问题

0 个答案: