//将原始视频的URL转化为NSData数据,写入沙盒
  + (void)videoWithUrl:(NSString *)url withFileName:(NSString *)fileName
  {
     ALAssetsLibrary *assetLibrary = [[ALAssetsLibrary alloc] init];
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),^{
      if (url) {
       [assetLibrary assetForURL:[NSURL URLWithString:url] resultBlock:^(ALAsset *asset) {
      ALAssetRepresentation *rep = [asset defaultRepresentation];
      NSString *pathDocuments = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
      NSString *imagePath = [NSString stringWithFormat:@"%@/Image", pathDocuments];
      NSString *dbFilePath = [imagePath stringByAppendingPathComponent:fileName];
      char const *cvideoPath = [dbFilePath UTF8String];
      FILE *file = fopen(cvideoPath, "a+");
      if (file) {
        const int bufferSize = 11024 * 1024;
        // 初始化一个1M的buffer
        Byte *buffer = (Byte*)malloc(bufferSize);
        NSUInteger read = 0, offset = 0, written = 0;
        NSError* err = nil;
        if (rep.size != 0)
        {
          do {
            read = [rep getBytes:buffer fromOffset:offset length:bufferSize error:&err];
            written = fwrite(buffer, sizeof(char), read, file);
            offset += read;
          } while (read != 0 && !err);//没到结尾，没出错，ok继续
        }
        // 释放缓冲区，关闭文件
        free(buffer);
        buffer = NULL;
        fclose(file);
        file = NULL;
      }
    } failureBlock:nil];
  }
});
}

+ (void) convertVideoWithModel:(RZProjectFileModel *) model
{
  model.filename = [NSString stringWithFormat:@"%ld.mp4",RandomNum];
  //保存至沙盒路径
  NSString *pathDocuments = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
  NSString *videoPath = [NSString stringWithFormat:@"%@/Image", pathDocuments];
  model.sandBoxFilePath = [videoPath stringByAppendingPathComponent:model.filename];

  //转码配置
  AVURLAsset *asset = [AVURLAsset URLAssetWithURL:model.assetFilePath options:nil];
  AVAssetExportSession *exportSession= [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetMediumQuality];
  exportSession.shouldOptimizeForNetworkUse = YES;
  exportSession.outputURL = [NSURL fileURLWithPath:model.sandBoxFilePath];
  exportSession.outputFileType = AVFileTypeMPEG4;
  [exportSession exportAsynchronouslyWithCompletionHandler:^{
     int exportStatus = exportSession.status;
    RZLog(@"%d",exportStatus);
    switch (exportStatus)
    {
      case AVAssetExportSessionStatusFailed:
      {
        // log error to text view
        NSError *exportError = exportSession.error;
        NSLog (@"AVAssetExportSessionStatusFailed: %@", exportError);
        break;
      }
      case AVAssetExportSessionStatusCompleted:
      {
        RZLog(@"视频转码成功");
        NSData *data = [NSData dataWithContentsOfFile:model.sandBoxFilePath];
        model.fileData = data;
      }
    }
    }];

}

exportSession.outputFileType = AVFileTypeMPEG4;

model.fileData = UIImageJPEGRepresentation(image, 0.4);

 MPMoviePlayerViewController* playerView = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL fileURLWithPath:sandBoxFilePath]];
[superVC presentViewController:playerView animated:YES completion:nil];