ios – OpenGL ES 2.0在iPad / iPhone上的视频

我正在为iPad 2上的视频编写一个OpenGL渲染缓冲区(使用iOS 4.3).这正是我正在尝试的：

A)设置一个AVAssetWriterInputPixelBufferAdaptor

>创建一个指向视频文件的AVAssetWriter
>使用适当的设置设置AVAssetWriterInput
>设置一个AVAssetWriterInputPixelBufferAdaptor将数据添加到视频文件

B)使用该AVAssetWriterInputPixelBufferAdaptor将数据写入视频文件

将OpenGL代码渲染到屏幕
>通过glreadPixels获取OpenGL缓冲区
>从OpenGL数据创建一个CVPixelBufferRef
>使用appendPixelBuffer方法将PixelBuffer附加到AVAssetWriterInputPixelBufferAdaptor

但是,我有这样做的问题.我现在的策略是在按下按钮时设置AVAssetWriterInputPixelBufferAdaptor.一旦AVAssetWriterInputPixelBufferAdaptor有效,我设置一个标志来发信号EAGLView创建一个像素缓冲区,并通过appendPixelBuffer将其附加到视频文件中,以获得给定的帧数.

现在我的代码崩溃,因为它试图附加第二个像素缓冲区,给我以下错误：

-[__NSCFDictionary appendPixelBuffer:withPresentationTime:]: unrecognized selector sent to instance 0x131db0

这是我的AVAsset设置代码(很多是基于Rudy aramayo的代码,它在正常图像上工作,但不是为纹理设置的)：

- (void) testVideoWriter {

  //initialize global info
  MOVIE_NAME = @"Documents/Movie.mov";
  CGSize size = CGSizeMake(480,320);
  frameLength = CMTimeMake(1,5); 
  currentTime = kCMTimeZero;
  currentFrame = 0;

  Nsstring *MOVIE_PATH = [NSHomeDirectory() stringByAppendingPathComponent:MOVIE_NAME];
  NSError *error = nil;

  unlink([betaCompressionDirectory UTF8String]);

  videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:betaCompressionDirectory] fileType:AVFileTypeQuickTimeMovie error:&error];

  NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264,AVVideoCodecKey,[NSNumber numberWithInt:size.width],AVVideoWidthKey,[NSNumber numberWithInt:size.height],AVVideoHeightKey,nil];
  writerInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];

  //writerInput.expectsMediaDataInRealTime = NO;

  NSDictionary *sourcePixelBufferAttributesDictionary = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInt:kCVPixelFormatType_32BGRA],kCVPixelBufferPixelFormatTypeKey,nil];

  adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput                                                                          sourcePixelBufferAttributes:sourcePixelBufferAttributesDictionary];
  [adaptor retain];

  [videoWriter addInput:writerInput];

  [videoWriter startWriting];
  [videoWriter startSessionAtSourceTime:kCMTimeZero];

  VIDEO_WRITER_IS_READY = true;
}

好的,现在我的videoWriter和适配器设置好了,我告诉我的OpenGL渲染器为每个帧创建一个像素缓冲区：

- (void) captureScreenVideo {

  if (!writerInput.readyForMoreMediaData) {
    return;
  }

  CGSize esize = CGSizeMake(eagl.backingWidth,eagl.backingHeight);
  NSInteger myDataLength = esize.width * esize.height * 4;
  gluint *buffer = (gluint *) malloc(myDataLength);
  glreadPixels(0,esize.width,esize.height,GL_RGBA,GL_UNSIGNED_BYTE,buffer);
  CVPixelBufferRef pixel_buffer = NULL;
  CVPixelBufferCreateWithBytes (NULL,kCVPixelFormatType_32BGRA,buffer,4 * esize.width,NULL,&pixel_buffer);

  /* DON'T FREE THIS BEFORE USING pixel_buffer! */ 
  //free(buffer);

  if(![adaptor appendPixelBuffer:pixel_buffer withPresentationTime:currentTime]) {
      NSLog(@"FAIL");
    } else {
      NSLog(@"Success:%d",currentFrame);
      currentTime = CMTimeAdd(currentTime,frameLength);
    }

   free(buffer);
   CVPixelBufferRelease(pixel_buffer);
  }


  currentFrame++;

  if (currentFrame > MAX_FRAMES) {
    VIDEO_WRITER_IS_READY = false;
    [writerInput markAsFinished];
    [videoWriter finishWriting];
    [videoWriter release];

    [self moveVideoToSavedPhotos]; 
  }
}

最后,我将视频移动到相机卷：

- (void) moveVideoToSavedPhotos {
  ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
  Nsstring *localVid = [NSHomeDirectory() stringByAppendingPathComponent:MOVIE_NAME];    
  NSURL* fileURL = [NSURL fileURLWithPath:localVid];

  [library writeVideoAtPathToSavedPhotosAlbum:fileURL
                              completionBlock:^(NSURL *assetURL,NSError *error) {
                                if (error) {   
                                  NSLog(@"%@: Error saving context: %@",[self class],[error localizedDescription]);
                                }
                              }];
  [library release];
}

但是,正如我所说,我正在打电话给appendPixelBuffer.

对不起,发送这么多的代码,但我真的不知道我做错了什么.更新将图像写入视频的项目似乎是微不足道的,但是我无法通过glreadPixels创建像素缓冲区并附加它.这让我疯狂！如果任何人有任何建议或OpenGL的工作代码示例 – >视频将是惊人的…谢谢！