AVPlayer视频播放的使用简介

首先我们定义变量：

    NSTimeInterval totalDration;

@property (strong, nonatomic) AVPlayer *player;
@property (retain, nonatomic) AVPlayerItem *playerItem;
@property (retain, nonatomic) id playbackTimeObserver;

而AVPlayer的使用离不开AVPlayerLayer，因此我们需要设置如下：

+ (Class)layerClass {
    return [AVPlayerLayer class];
}

- (AVPlayer *)player {
    return [(AVPlayerLayer *)[self layer] player];
}

- (void)setPlayer:(AVPlayer *)player {
    [(AVPlayerLayer *)[self layer] setPlayer:player];
}

视频播放的初始化

        self.playerItem = [[[AVPlayerItem alloc]initWithURL:_videoURL] autorelease];

        [self.playerItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];
        [self.playerItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];

        self.player = [[[AVPlayer alloc]initWithPlayerItem:self.playerItem] autorelease];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(videoPlayDidEnd:) name:AVPlayerItemDidPlayToEndTimeNotification object:self.playerItem];

        [(AVPlayerLayer*)[self layer] setVideoGravity:AVLayerVideoGravityResizeAspect];

添加的observer可以监控缓存进度及播放进度

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

    AVPlayerItem *playerItem = (AVPlayerItem *)object;

    if ([keyPath isEqualToString:@"status"]) {

        if ([playerItem status] == AVPlayerStatusReadyToPlay) {
            // ready to play
            NSLog(@"AVPlayerStatusReadyToPlay");
            CMTime duration = self.playerItem.duration;// 获取视频总长度
            totalDration = playerItem.duration.value / playerItem.duration.timescale;// 转换成秒
            // 可以更新视频总长度

            if (_didEnterFullScreenMode  && !_is_s_video) {
                [self monitoringPlayback:self.playerItem];// 监听播放状态
            }

        }
        else if ([playerItem status] == AVPlayerStatusFailed) {

            NSLog(@"AVPlayerStatusFailed");
                // 播放失败的处理
        }

    }
    else if ([keyPath isEqualToString:@"loadedTimeRanges"]) {

        NSTimeInterval timeInterval = [self availableDuration];// 计算缓冲进度
        CMTime duration = self.playerItem.duration;
        CGFloat totalDuration = CMTimeGetSeconds(duration);
        // 更新缓存进度

    }
}

- (void)monitoringPlayback:(AVPlayerItem *)playerItem {
    self.playbackTimeObserver = [self.player addPeriodicTimeObserverForInterval:CMTimeMake(1, 1) queue:NULL usingBlock:^(CMTime time) {
        CGFloat currentSecond = playerItem.currentTime.value/playerItem.currentTime.timescale;// 计算当前在第几秒
       // 更新播放进度

    }];

}

需要注意的是playerItem销毁前一定先移除observer

        [self.playerItem removeObserver:self forKeyPath:@"status"];
        [self.playerItem removeObserver:self forKeyPath:@"loadedTimeRanges"];

通过slide或者其他方式改变播放进度：

    CGFloat value = progressView.progressValue;
    CGFloat curTime = value * totalDration;
    CMTime time = CMTimeMake(curTime, 1);
    [self.player pause]；
    [self.player seekToTime:time completionHandler:^(BOOL f){
        [self.player play];
    }];

在完成了视频播放，经过尝试需要设置如下才可以继续播放：

    // 初始化值
    [self.playerItem setReversePlaybackEndTime:kCMTimeZero];
    [self.playerItem seekToTime:kCMTimeZero];

关于视频播放音量的设置，如下：

- (void) setVolome:(CGFloat) volome {
    if (self.playerItem == nil) {
        return;
    }
    if (volome > 1) {
        volome = 1;
    }
    if (volome < 0) {
        volome = 0;
    }
    NSArray *audioTracks = [_playerItem.asset tracksWithMediaType:AVMediaTypeAudio];

    NSMutableArray *allAudioParams = [NSMutableArray array];

    for (AVAssetTrack *track in audioTracks) {
        AVMutableAudioMixInputParameters *audioInputParams =
        [AVMutableAudioMixInputParameters audioMixInputParameters];
        [audioInputParams setVolume:volome atTime:kCMTimeZero];
        [audioInputParams setTrackID:[track trackID]];
        [allAudioParams addObject:audioInputParams];
    }

    AVMutableAudioMix *audioMix = [AVMutableAudioMix audioMix];
    [audioMix setInputParameters:allAudioParams];
    [_playerItem setAudioMix:audioMix];
}