iphone – AVCapture appendSampleBuffer

概述我对这个感到疯狂 – 到处寻找并尝试了我能想到的一切. 我正在制作一款使用AVFoundation的iPhone应用程序 – 特别是使用iPhone相机捕捉视频的AVCapture. 我需要在录制中包含的视频源上叠加自定义图像. 到目前为止,我已经设置了AVCapture会话,可以显示提要,访问框架,将其保存为UIImage,并将叠加图像放在上面.然后将这个新的UIImage转换为CVPixelB 我对这个感到疯狂 – 到处寻找并尝试了我能想到的一切.

我正在制作一款使用AVFoundation的iPhone应用程序 – 特别是使用iPhone相机捕捉视频的AVCapture.

我需要在录制中包含的视频源上叠加自定义图像.

到目前为止,我已经设置了AVCapture会话,可以显示提要,访问框架,将其保存为UIImage,并将叠加图像放在上面.然后将这个新的UIImage转换为CVPixelBufferRef.为了仔细检查bufferRef是否正常工作,我将其转换回UIImage,它仍然可以显示图像.

当我尝试将CVPixelBufferRef转换为CMSampleBufferRef以附加到AVCaptureSessions assetWriterinput时,麻烦就开始了. CMSampleBufferRef在我尝试创建它时总是返回NulL.

这是 – (voID)captureOutput函数

- (voID)captureOutput:(AVCaptureOutput *)captureOutput dIDOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer     fromConnection:(AVCaptureConnection *)connection{  UIImage *botimage = [self imageFromSampleBuffer:sampleBuffer]; UIImage *wheel = [self imageFromVIEw:wheelVIEw]; UIImage *finalimage = [self overlaIDImage:botimage :wheel]; //[prevIEwImage setimage:finalimage]; <- works -- the image is being merged into one UIImage CVPixelBufferRef pixelBuffer = NulL; CGImageRef cgImage = CGImageCreatecopy(finalimage.CGImage); CFDataRef image = CGDataProvIDercopyData(CGImageGetDataProvIDer(cgImage)); int status = CVPixelBufferCreateWithBytes(NulL,self.vIEw.bounds.size.wIDth,self.vIEw.bounds.size.height,kCVPixelFormatType_32BGRA,(voID*)CFDataGetBytePtr(image),CGImageGetBytesPerRow(cgImage),NulL,&pixelBuffer); if(status == 0){  Osstatus result = 0;  CMVIDeoFormatDescriptionRef vIDeoInfo = NulL;  result = CMVIDeoFormatDescriptionCreateForImageBuffer(NulL,pixelBuffer,&vIDeoInfo);  NSParameterassert(result == 0 && vIDeoInfo != NulL);  CMSampleBufferRef myBuffer = NulL;  result = CMSampleBufferCreateForImageBuffer(kcfAllocatorDefault,true,vIDeoInfo,&myBuffer);  NSParameterassert(result == 0 && myBuffer != NulL);//always null :S  NSLog(@"Trying to append");  if (!CMSampleBufferDataIsReady(myBuffer)){   NSLog(@"sampleBuffer data is not ready");   return;  }  if (![assetWriterinput isReadyForMoreMediaData]){   NSLog(@"Not ready for data :(");   return;  }  if (![assetWriterinput appendSampleBuffer:myBuffer]){      NSLog(@"Failed to append pixel buffer");  } }}

我一直听到的另一个解决方案是使用AVAssetWriterinputPixelBufferAdaptor,它不需要进行凌乱的CMSampleBufferRef包装.但是,我已经搜索了堆叠和苹果开发者论坛和文档,但无法找到关于如何设置或如何使用它的清晰描述或示例.如果有人有一个可行的例子,请你告诉我或者帮我解决上面的问题 – 一直在这个不停的工作一周,我在智慧结束.

如果您需要任何其他信息,请告诉我

提前致谢,

迈克尔

解决方法 你需要AVAssetWriterinputPixelBufferAdaptor,这里是创建它的代码：

// Create dictionary for pixel buffer adaptorNSDictionary *bufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA],kCVPixelBufferPixelFormatTypeKey,nil];// Create pixel buffer adaptorm_pixelsBufferAdaptor = [[AVAssetWriterinputPixelBufferAdaptor alloc] initWithAssetWriterinput:assetWriterinput sourcePixelBufferAttributes:bufferAttributes];

以及使用它的代码：

// If ready to have more media dataif (m_pixelsBufferAdaptor.assetWriterinput.readyForMoreMediaData) {    // Create a pixel buffer    CVPixelBufferRef pixelsBuffer = NulL;    CVPixelBufferPoolCreatePixelBuffer(NulL,m_pixelsBufferAdaptor.pixelBufferPool,&pixelsBuffer);    // Lock pixel buffer address    CVPixelBufferLockBaseAddress(pixelsBuffer,0);    // Create your function to set your pixels data in the buffer (in your case,fill with your finalimage data)    [self yourFunctiontoputDataInPixelBuffer:CVPixelBufferGetBaseAddress(pixelsBuffer)];    // Unlock pixel buffer address    CVPixelBufferUnlockBaseAddress(pixelsBuffer,0);    // Append pixel buffer (calculate currentFrameTime with your needing,the most simplest way is to have a frame time starting at 0 and increment each time you write a frame with the time of a frame (inverse of your framerate))    [m_pixelsBufferAdaptor appendPixelBuffer:pixelsBuffer withPresentationTime:currentFrameTime];    // Release pixel buffer    CVPixelBufferRelease(pixelsBuffer);}

并且不要忘记释放您的pixelsBufferAdaptor.

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