command + s 截模拟器的屏幕

MP.4只是一个容器     H.264 H.263是真正的格式 H.265正在测试中

avi H.264 H.263

 

视频解码：将H.263  H.264转换为视频和音频的格式

视频编码：

 

 解码：硬解码：GPU做的解码     CPU做除了图片以外的，其他的处理    GPU（解码的效率特别快）显卡上带的 和图片有关

      软解码：CPU做的解码（前提是GPU不能做相应的解码时）

      硬解码比软解码强一点

一 、AVPlayer

  播放视频    可以播放流媒体   导入两个库  CoreMedia  AVFoundation

单独使用AVPlayer类是无法显示视频的，要将视频层添加值AVPlayerLayer中，这样才能将视频显示出来

NSURL * url = [NSURL fileURLWithPath:path];不是规范的path（NSString）时，使用该方法初始化NSURL

CMTimeGetSeconds(currentTime)转为秒

   //AVAudioPlayer->url

    //AVPlayer-?AVPlayerItem->AVURLAsset->NSURL

    NSString * path = [[NSBundle mainBundle]pathForResource:@"敢死队3" ofType:@"mp4"];

    NSURL * url = [NSURL fileURLWithPath:path];

    AVURLAsset *asset = [AVURLAsset assetWithURL:url];

    //1、异步 检测

    [asset loadValuesAsynchronouslyForKeys:@[@"tracks"] completionHandler:^{

        //AVPlayerItem

        AVPlayerItem * item = [AVPlayerItem playerItemWithAsset:asset];

        _player = [[AVPlayer alloc]initWithPlayerItem:item];

        //关联屏幕和播放器

        [_playerView setPlayer:_player];

        

        //刷新进度

        //这个方法就是加一个监听  每隔这么长时间会再者个线程里面调用这个方法   CMTimeMake(<#int64_t value#>, <#int32_t timescale#>)  帧 帧/每秒

        __weak AVPlayer * player = _player;

        __weak UISlider * slider = _slider;

       [ _player addPeriodicTimeObserverForInterval:CMTimeMake(1, 1) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {

            //当前时间 警告的原因是相互强引用

           CMTime currentTime = player.currentItem.currentTime;

           //总时间

           CMTime duration = player.currentItem.duration;

           //CMTimeGetSeconds  转为秒

           float pro = CMTimeGetSeconds(currentTime)/CMTimeGetSeconds(duration);

           [slider setValue:pro animated:YES];

        }];

        }];

    

}

//设置进度

-(void)setProgress

{

    CMTime duration = _player.currentItem.duration;//总时间

    CMTime currentTime = CMTimeMultiplyByFloat64(duration, _slider.value);

    //从当前时间播放

    [_player seekToTime:currentTime];

}

-(void)play

{

    [_player play];

}

-(void)pause

{

    [_player pause];

}

二、MPMoviePlayerController  视频播放器 不能播放流媒体

需要导入MediaPlayer库

 MPMoviePlayerViewController * _playerController;//不能播放流媒体 流媒体可以想一想直播

- (IBAction)buttonClick:(UIButton *)sender {

    NSString * path = [[NSBundle mainBundle]pathForResource:@"敢死队3" ofType:@"mp4"];

    NSURL * url = [NSURL fileURLWithPath:path];

    _playerController = [[MPMoviePlayerViewController alloc]initWithContentURL:url];

    [self presentMoviePlayerViewControllerAnimated:_playerController];

    

}

三、AVAudioPlayer  音频播放器 引入AVFoundition

- (void)viewDidLoad {

    [super viewDidLoad];

    NSString* path = [[NSBundle mainBundle] pathForResource:@"Beat It" ofType:@"mp3"];

    NSURL* url = [NSURL fileURLWithPath:path];

    _player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];

    //准备播放

    [_player prepareToPlay];

    //变速

    [_player setEnableRate:YES];

    //峰值和平均值监测

    [_player setMeteringEnabled:YES];

}

//刷新

- (void)refresh{

    //进度 = 当前时间 / 总时间

    [_proSlider setValue:_player.currentTime/_player.duration animated:YES];

    

    //刷新峰值平均值

    [_player updateMeters];

    //平均值

    float avg = [_player averagePowerForChannel:0];

    //峰值

    float peak = [_player peakPowerForChannel:0];

    //NSLog(@"%f, %f", avg, peak);

    [_pv1 setProgress: (avg + 30) / 30 animated:YES];

    [_pv2 setProgress: (peak + 30) / 30 animated:YES];

}

//播放

- (void)play:(id)sender{

    [_player play];

    if (_timer == nil) {

        _timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(refresh) userInfo:nil repeats:YES];

    }

}

//暂停

- (void)pause:(id)sender{

    [_player pause];

    if (_timer) {

        [_timer invalidate];

        _timer = nil;

    }

}

//设置进度

- (IBAction)setProgress:(id)sender{

    //当前时间 = 总时间 * 百分比

    UISlider* slider = sender;

    _player.currentTime = _player.duration * slider.value;

}

//设置音量

- (IBAction)setVolume:(id)sender{

    UISlider* slider = sender;

    _player.volume = slider.value;

}

//设置声道

- (IBAction)setPan:(id)sender{

    UISlider* slider = sender;

    _player.pan = slider.value;

}

//设置速度

- (IBAction)setRate:(id)sender{

    UISlider* slider = sender;

    _player.rate = slider.value;

}

四、AVAUdioRecorder  录音  引入AVFoundition系统库

  //录音设置

    NSMutableDictionary * recordSetting = [[NSMutableDictionary alloc]init];

    //设置录音格式  AVFormatIDKey == kAudioFormatLinearPCM

    [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];

    //设置录音采用率（Hz）如：AVSampleRateKey == 8000/44100/96000(影响音频质量)

    [recordSetting setValue:[NSNumber numberWithFloat:44100] forKey:AVSampleRateKey];

    //录音通道数 1 或 2

    [recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];

    //线性采样位数 8.16。24.32

    [recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];

    //录音质量

    [recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];

    _recorder = [[AVAudioRecorder alloc]initWithURL:url settings:recordSetting error:nil];

    [_recorder prepareToRecord];

-(void)startRecord

{

    [_button setTitle:@"录音中" forState:UIControlStateNormal];

    [_recorder record];

}

-(void)stopRecord

{

    [_button setTitle:@"录音" forState:UIControlStateNormal];

    [_recorder stop];

    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Document/a.aac"];

    NSURL * url = [NSURL fileURLWithPath:path];

    NSLog(@"录音路径%@",path);

    _player = [[AVAudioPlayer alloc]initWithContentsOfURL:url

                                                error:nil];

    [_player prepareToPlay];

    [_player play];

}