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，我将它转换回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,
0,
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,
pixelBuffer, true, NULL, NULL, videoInfo, NULL, &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");
}
}
}
没有找到相关结果
已邀请:
2 个回复
锯康
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); }屠创氓读叔
OSStatus ret = 0; CMSampleBufferRef sample = NULL; CMVideoFormatDescriptionRef videoInfo = NULL; CMSampleTimingInfo timingInfo = kCMTimingInfoInvalid; timingInfo.presentationTimeStamp = pts; timingInfo.duration = duration; ret = CMVideoFormatDescriptionCreateForImageBuffer(NULL, pixel, &videoInfo); if (ret != 0) { NSLog(@"CMVideoFormatDescriptionCreateForImageBuffer failed! %d", (int)ret); goto done; } ret = CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault, pixel, true, NULL, NULL, videoInfo, &timingInfo, &sample); if (ret != 0) { NSLog(@"CMSampleBufferCreateForImageBuffer failed! %d", (int)ret); goto done; }