GPUImage源码解读(十二)

GPUImageMovie 主要的作用是读取与解码音视频文件。它继承自GPUImageOutput，可以输出帧缓存对象，由于没有实现GPUImageInput协议，因此只能作为响应源。 -初始化。可以通过NSURL、AVPlayerItem、AVAsset初始化。

- (id)initWithAsset:(AVAsset *)asset;
- (id)initWithPlayerItem:(AVPlayerItem *)playerItem;
- (id)initWithURL:(NSURL *)url;

初始化相对简单，只是简单保存传入数据。

- (id)initWithURL:(NSURL *)url;
{
    if (!(self = [super init]))
    {
        return nil;
    }

    [self yuvConversionSetup];

    self.url = url;
    self.asset = nil;

    return self;
}

- (id)initWithAsset:(AVAsset *)asset;
{
    if (!(self = [super init]))
    {
      return nil;
    }

    [self yuvConversionSetup];

    self.url = nil;
    self.asset = asset;

    return self;
}

- (id)initWithPlayerItem:(AVPlayerItem *)playerItem;
{
    if (!(self = [super init]))
    {
        return nil;
    }

    [self yuvConversionSetup];

    self.url = nil;
    self.asset = nil;
    self.playerItem = playerItem;

    return self;
}

• 其实方法

  ```

  // 允许使用GPUImageMovieWriter进行音视频同步编码

• (void)enableSynchronizedEncodingUsingMovieWriter:(GPUImageMovieWriter *)movieWriter;

  // 读取音视频

• (BOOL)readNextVideoFrameFromOutput:(AVAssetReaderOutput *)readerVideoTrackOutput;

• (BOOL)readNextAudioSampleFromOutput:(AVAssetReaderOutput *)readerAudioTrackOutput;

  // 开始、结束、取消读取

• (void)startProcessing;

• (void)endProcessing;

• (void)cancelProcessing;

  // 处理视频帧

• (void)processMovieFrame:(CMSampleBufferRef)movieSampleBuffer;

  ```

  未完.............