iOS開發(fā)常用的兩種視頻播放方式，一種是使用MPMoviePlayerController，還有就是使用AVPlayer。MPMoviePlayerController系統(tǒng)高度封裝使用起來(lái)很方便，但是如果要高度自定義播放器就比較麻煩。而AVPlayer則恰好相反，靈活性更強(qiáng)，使用起來(lái)也麻煩一點(diǎn)。本文將對(duì)AVPlayer的使用做個(gè)簡(jiǎn)單的介紹。

1、AVPlayer加載播放視頻

AVPlayer繼承NSObject，所以單獨(dú)使用AVPlayer時(shí)無(wú)法顯示視頻的，必須將視頻圖層添加到AVPlayerLayer中方能顯示視頻。使用AVPlayer首先了解一下幾個(gè)常用的類：

AVAsset：AVAsset類專門用于獲取多媒體的相關(guān)信息,包括獲取多媒體的畫面、聲音等信息。
AVURLAsset：AVAsset的子類，可以根據(jù)一個(gè)URL路徑創(chuàng)建一個(gè)包含媒體信息的AVURLAsset對(duì)象。
AVPlayerItem：一個(gè)媒體資源管理對(duì)象，管理者視頻的一些基本信息和狀態(tài)，一個(gè)AVPlayerItem對(duì)應(yīng)著一個(gè)視頻資源。

AVPlayer加載視頻的代碼如下：

    AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:[NSURL URLWithString:@"http://bos.nj.bpc.baidu.com/tieba-smallvideo/11772_3c435014fb2dd9a5fd56a57cc369f6a0.mp4"]];
    //添加監(jiān)聽
    [playerItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];
    [playerItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];
    self.avPlayer = [AVPlayer playerWithPlayerItem:playerItem];
    
    AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.avPlayer];
    //設(shè)置模式
    playerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    playerLayer.contentsScale = [UIScreen mainScreen].scale;
    playerLayer.frame = CGRectMake(0, 100, self.view.bounds.size.width, 200);
    [self.view.layer addSublayer:playerLayer];



//監(jiān)聽回調(diào)
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
{
    AVPlayerItem *playerItem = (AVPlayerItem *)object;
    
    if ([keyPath isEqualToString:@"loadedTimeRanges"]){
        
    }else if ([keyPath isEqualToString:@"status"]){
        if (playerItem.status == AVPlayerItemStatusReadyToPlay){
            NSLog(@"playerItem is ready");
            [self.avPlayer play];
        } else{
            NSLog(@"load break");
        }
    }
}

此處代碼中添加了對(duì)AVPlayerItem的"loadedTimeRanges"和"status"屬性監(jiān)聽，status枚舉值有 AVPlayerItemStatusUnknown,AVPlayerItemStatusReadyToPlay, AVPlayerItemStatusFailed。只有當(dāng)status為AVPlayerItemStatusReadyToPlay是調(diào)用 AVPlayer的play方法視頻才能播放。

運(yùn)行效果

D82C00B0-4D83-4B1A-82EC-B245F15F40E0.png

2、AVPlayer當(dāng)前緩沖進(jìn)度以及當(dāng)前播放進(jìn)度的處理

獲取視頻當(dāng)前的緩沖進(jìn)度：

通過(guò)監(jiān)聽AVPlayerItem的"loadedTimeRanges"，可以實(shí)時(shí)知道當(dāng)前視頻的進(jìn)度緩沖，計(jì)算方法如下：

- (NSTimeInterval)availableDurationWithplayerItem:(AVPlayerItem *)playerItem
{
    NSArray *loadedTimeRanges = [playerItem loadedTimeRanges];
    CMTimeRange timeRange = [loadedTimeRanges.firstObject CMTimeRangeValue];// 獲取緩沖區(qū)域
    NSTimeInterval startSeconds = CMTimeGetSeconds(timeRange.start);
    NSTimeInterval durationSeconds = CMTimeGetSeconds(timeRange.duration);
    NSTimeInterval result = startSeconds + durationSeconds;// 計(jì)算緩沖總進(jìn)度
    return result;
}

獲取視頻當(dāng)前的播放進(jìn)度：

    //視頻當(dāng)前的播放進(jìn)度
    NSTimeInterval current = CMTimeGetSeconds(self.avPlayer.currentTime);
    //視頻的總長(zhǎng)度
    NSTimeInterval total = CMTimeGetSeconds(self.avPlayer.currentItem.duration);

AVPlayer提供了一個(gè)Block回調(diào)，當(dāng)播放進(jìn)度改變的時(shí)候回主動(dòng)回調(diào)該Block，但是當(dāng)視頻卡頓的時(shí)候是不會(huì)回調(diào)的，可以在該回調(diào)里面處理進(jìn)度條以及播放時(shí)間的刷新，詳細(xì)方法如下：

     __weak __typeof(self) weakSelf = self;
    [self.avPlayer addPeriodicTimeObserverForInterval:CMTimeMake(1, 1) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {
        //當(dāng)前播放的時(shí)間
        NSTimeInterval current = CMTimeGetSeconds(time);
        //視頻的總時(shí)間
        NSTimeInterval total = CMTimeGetSeconds(weakSelf.avPlayer.currentItem.duration);
        //設(shè)置滑塊的當(dāng)前進(jìn)度
        weakSelf.slider.sliderPercent = current/total;
        NSLog(@"%f", weakSelf.slider.sliderPercent);
       //設(shè)置時(shí)間
        weakSelf.timeLabel.text = [NSString stringWithFormat:@"%@/%@", [weakSelf formatPlayTime:current], [weakSelf formatPlayTime:total]];
    }];


//將時(shí)間轉(zhuǎn)換成00:00:00格式
- (NSString *)formatPlayTime:(NSTimeInterval)duration
{
    int minute = 0, hour = 0, secend = duration;
    minute = (secend % 3600)/60;
    hour = secend / 3600;
    secend = secend % 60;
    return [NSString stringWithFormat:@"%02d:%02d:%02d", hour, minute, secend];
}

改變視頻當(dāng)前的播放進(jìn)度：

當(dāng)滑塊滑動(dòng)的時(shí)候需要改變當(dāng)前視頻的播放進(jìn)度，代碼如下：

//處理滑塊
- (void)progressValueChange:(AC_ProgressSlider *)slider
{
       //當(dāng)視頻狀態(tài)為AVPlayerStatusReadyToPlay時(shí)才處理（當(dāng)視頻沒(méi)加載的時(shí)候，直接禁止掉滑塊事件）
       if (self.avPlayer.status == AVPlayerStatusReadyToPlay) {
        NSTimeInterval duration = self.slider.sliderPercent* CMTimeGetSeconds(self.avPlayer.currentItem.duration);
        CMTime seekTime = CMTimeMake(duration, 1);

        [self.avPlayer seekToTime:seekTime completionHandler:^(BOOL finished) {

        }];
    }
}

播放進(jìn)度控件的定制：

該控件應(yīng)該包含4個(gè)部分，總進(jìn)度、緩沖進(jìn)度、當(dāng)前播放進(jìn)度還有一個(gè)滑塊。效果圖如下：

08D61DA5-5645-4B1D-A170-ABAAB6088B19.png

最簡(jiǎn)單的實(shí)現(xiàn)方式是UIProgressView跟UISlider兩個(gè)控件疊加起來(lái)，效果不是太好。demo是自定義的UIControl，詳細(xì)實(shí)現(xiàn)方式請(qǐng)查看demo中的AC_ProgressSlider類。

當(dāng)視頻卡頓的時(shí)候處理旋轉(zhuǎn)loading方法：

上面說(shuō)過(guò)- (id)addPeriodicTimeObserverForInterval:(CMTime)interval queue:(nullable dispatch_queue_t)queue usingBlock:(void (^)(CMTime time))block;該方法在卡頓的時(shí)候不會(huì)回調(diào)，所以只用該方法處理不了這種情況。我好像也沒(méi)找到相關(guān)的api，所以demo中采用的是開啟定時(shí)器，然后用一個(gè)lastTime保留當(dāng)前的播放進(jìn)度，當(dāng)下次調(diào)用的時(shí)候用lastTime跟當(dāng)前的進(jìn)度進(jìn)行比較，如果相等說(shuō)明播放卡頓了，代碼如下：

    self.link = [CADisplayLink displayLinkWithTarget:self selector:@selector(upadte)];
    [self.link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

//更新方法
- (void)upadte
{
    NSTimeInterval current = CMTimeGetSeconds(self.avPlayer.currentTime);
    NSTimeInterval total = CMTimeGetSeconds(self.avPlayer.currentItem.duration);
   //如果用戶在手動(dòng)滑動(dòng)滑塊，則不對(duì)滑塊的進(jìn)度進(jìn)行設(shè)置重繪
    if (!self.slider.isSliding) {
        self.slider.sliderPercent = current/total;
    }
    
    if (current!=self.lastTime) {
        [self.activity stopAnimating];
        self.timeLabel.text = [NSString stringWithFormat:@"%@/%@", [self formatPlayTime:current], [self formatPlayTime:total]];
    }else{
        [self.activity startAnimating];
    }
    self.lastTime = current;
}

3、AVPlayer播放暫停的處理

這個(gè)比較簡(jiǎn)單、 分別是pause和play方法

//播放暫停按鈕
- (void)playOrPauseAction:(UIButton *)sender
{
    sender.selected = !sender.selected;
    
    if (self.avPlayer.rate == 1) {
        [self.avPlayer pause];
        self.link.paused = YES;
        [self.activity stopAnimating];
    } else {
        [self.avPlayer play];
        self.link.paused = NO;
    }
}

4、AVPlayer播放完成的處理

添加通知即可

 //播放完成通知
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(moviePlayDidEnd)
                                                 name:AVPlayerItemDidPlayToEndTimeNotification
                                               object:nil];

5、更換當(dāng)前播放的AVPlayerItem

當(dāng)視頻播放完時(shí)或者用戶切換不同的視頻時(shí)候就要更換當(dāng)前的視頻，代碼如下：

//切換當(dāng)前播放的內(nèi)容
- (void)changeCurrentplayerItemWithAC_VideoModel:(AC_VideoModel *)model
{
    if (self.avPlayer) {
        
        //由暫停狀態(tài)切換時(shí)候 開啟定時(shí)器，將暫停按鈕狀態(tài)設(shè)置為播放狀態(tài)
        self.link.paused = NO;
        self.playButton.selected = NO;
        
        //移除當(dāng)前AVPlayerItem對(duì)"loadedTimeRanges"和"status"的監(jiān)聽
        [self removeObserveWithPlayerItem:self.avPlayer.currentItem];
        AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:model.url];
        [self addObserveWithPlayerItem:playerItem];
        self.avPlayerItem = playerItem;
        //更換播放的AVPlayerItem
        [self.avPlayer replaceCurrentItemWithPlayerItem:playerItem];
        
        self.playButton.enabled = NO;
        self.slider.enabled = NO;
    }
}

感覺寫的有點(diǎn)亂，詳細(xì)的看demo吧，demo運(yùn)行效果如下：

海賊王.gif