iphone – AVCapture appendSampleBuffer
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 adaptor NSDictionary *bufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA],kCVPixelBufferPixelFormatTypeKey,nil]; // Create pixel buffer adaptor m_pixelsBufferAdaptor = [[AVAssetWriterInputPixelBufferAdaptor alloc] initWithAssetWriterInput:assetWriterInput sourcePixelBufferAttributes:bufferAttributes]; 以及使用它的代码: // If ready to have more media data if (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. (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |