详解iOS视频播放方式

// 初始化KRVideoPlayerController- (instancetype)initWithFrame:(CGRect)frame{ self = [super init]; if (self) { self.view.frame = frame; self.view.backgroundColor = [UIColor blackColor]; self.controlStyle = MPMovieControlStyleNone; [self.view addSubview:self.videoControl]; self.videoControl.frame = self.view.bounds; [self configObserver]; [self configControlAction]; } return self;}// 懒加载KRVideoPlayerControlView- (KRVideoPlayerControlView *)videoControl{ if (!_videoControl) { _videoControl = [[KRVideoPlayerControlView alloc] init]; } return _videoControl;}

// 1、即将开始画中画- (void)playerViewControllerWillStartPictureInPicture:(AVPlayerViewController *)playerViewController;// 2、开始画中画- (void)playerViewControllerDidStartPictureInPicture:(AVPlayerViewController *)playerViewController;// 3、画中画失败- (void)playerViewController:(AVPlayerViewController *)playerViewController failedToStartPictureInPictureWithError:(NSError *)error;// 4、即将结束画中画- (void)playerViewControllerWillStopPictureInPicture:(AVPlayerViewController *)playerViewController;// 5、结束画中画- (void)playerViewControllerDidStopPictureInPicture:(AVPlayerViewController *)playerViewController; 

- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. self.view.backgroundColor = [UIColor whiteColor];  self.avPlayerItem = [AVPlayerItem playerItemWithURL:[NSURL URLWithString:MovieURL]]; self.avPlayer = [[AVPlayer alloc]initWithPlayerItem:self.avPlayerItem]; self.avPlayerLayer = [AVPlayerLayer playerLayerWithPlayer:self.avPlayer]; self.avPlayerLayer.frame = CGRectMake(10, 100, 355, 200); [self.view.layer addSublayer:self.avPlayerLayer]; // 添加观察者 [self addObserverWithAVPlayerItem];}#pragma mark --#pragma mark -- KVO-(void)addObserverWithAVPlayerItem{ //状态添加观察者 [self.avPlayerItem addObserver:self forKeyPath:@"status" options:(NSKeyValueObservingOptionNew) context:nil]; // 缓存进度添加观察者 [self.avPlayerItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];}-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{ AVPlayerItem * avplayeritem = (AVPlayerItem *)object; if ([keyPath isEqualToString:@"status"]) { AVPlayerStatus status = [[change objectForKey:@"new"] intValue]; if (status == AVPlayerStatusReadyToPlay) {  NSLog(@"准备好播放");  CMTime duration = avplayeritem.duration;  NSLog(@"视频总时长:%.2f",CMTimeGetSeconds(duration));  // 播放  [self.avPlayer play]; }else if (status == AVPlayerStatusFailed){  NSLog(@"视频准备发生错误"); }else{  NSLog(@"位置错误"); } }else if ([keyPath isEqualToString:@"loadedTimeRanges"]){  // 可以自定义缓存进度  NSTimeInterval timeInterval = [self alreadyCacheVideoProgress];  NSLog(@"视频已经缓存的时长:%.2f",timeInterval); }}#pragma mark --#pragma mark -- alreadyCacheVideoProgress-(NSTimeInterval)alreadyCacheVideoProgress{  // 先获取到它的缓存的进度 NSArray * cacheVideoTime = [self.avPlayerItem loadedTimeRanges]; // CMTimeRange 结构体 start duration 表示起始位置 和 持续时间 // 获取缓冲区域 CMTimeRange timeRange = [cacheVideoTime.firstObject CMTimeRangeValue]; float startSeconds = CMTimeGetSeconds(timeRange.start); float durationSeconds = CMTimeGetSeconds(timeRange.duration); // 计算总缓冲时间 = start + duration NSTimeInterval result = startSeconds + durationSeconds; return result;} 

/*!	@typedef	CMTime	@abstract	Rational time value represented as int64/int32.*/typedef struct{	CMTimeValue	value;		/*! @field value The value of the CMTime. value/timescale = seconds. 帧数 */	CMTimeScale	timescale;	/*! @field timescale The timescale of the CMTime. value/timescale = seconds.帧率（影片每秒有几帧）*/ CMTimeFlags flags; /*! @field flags The flags, eg. kCMTimeFlags_Valid, kCMTimeFlags_PositiveInfinity, etc. */  CMTimeEpoch epoch; /*! @field epoch Differentiates between equal timestamps that are actually different because of looping, multi-item sequencing, etc. Will be used during comparison: greater epochs happen after lesser ones. Additions/subtraction is only possible within a single epoch, however, since epoch length may be unknown/variable. */} CMTime;

CMTime duration = avplayeritem.duration;NSLog(@"视频总时长:%.2f",CMTimeGetSeconds(duration));

- (id)addPeriodicTimeObserverForInterval:(CMTime)interval queue:(nullable dispatch_queue_t)queue usingBlock:(void (^)(CMTime time))block;

[self.avPlayer addPeriodicTimeObserverForInterval:CMTimeMake(1, 10) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {  // CMTime的timescale的定义帮助理解下面代码  // @field timescale The timescale of the CMTime. value/timescale = seconds.  float currentPlayTime = (double)self.avPlayerItem.currentTime.value/ self.avPlayerItem.currentTime.timescale;  NSLog(@"当前播放进度：%f",currentPlayTime); }];

/* Note that NSNotifications posted by AVPlayerItem may be posted on a different thread from the one on which the observer was registered. */// notifications          descriptionAVF_EXPORT NSString *const AVPlayerItemTimeJumpedNotification			 NS_AVAILABLE(10_7, 5_0);	// the item's current time has changed discontinuouslyAVF_EXPORT NSString *const AVPlayerItemDidPlayToEndTimeNotification NS_AVAILABLE(10_7, 4_0); // item has played to its end timeAVF_EXPORT NSString *const AVPlayerItemFailedToPlayToEndTimeNotification NS_AVAILABLE(10_7, 4_3); // item has failed to play to its end timeAVF_EXPORT NSString *const AVPlayerItemPlaybackStalledNotification NS_AVAILABLE(10_9, 6_0); // media did not arrive in time to continue playbackAVF_EXPORT NSString *const AVPlayerItemNewAccessLogEntryNotification	 NS_AVAILABLE(10_9, 6_0);	// a new access log entry has been addedAVF_EXPORT NSString *const AVPlayerItemNewErrorLogEntryNotification		 NS_AVAILABLE(10_9, 6_0);	// a new error log entry has been added// notification userInfo key         typeAVF_EXPORT NSString *const AVPlayerItemFailedToPlayToEndTimeErrorKey NS_AVAILABLE(10_7, 4_3); // NSError