我正在我的iOS应用中录制实时视频。在另一个Stack Overflow页面上,我发现可以使用vImage_Buffer
处理我的帧。
问题是我不知道如何从输出的vImage_buffer
返回CVPixelBufferRef
。
这是在另一篇文章中给出的代码:
NSInteger cropX0 = 100,
cropY0 = 100,
cropHeight = 100,
cropWidth = 100,
outWidth = 480,
outHeight = 480;
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer,0);
void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
vImage_Buffer inBuff;
inBuff.height = cropHeight;
inBuff.width = cropWidth;
inBuff.rowBytes = bytesPerRow;
int startpos = cropY0 * bytesPerRow + 4 * cropX0;
inBuff.data = baseAddress + startpos;
unsigned char *outImg = (unsigned char*)malloc(4 * outWidth * outHeight);
vImage_Buffer outBuff = {outImg, outHeight, outWidth, 4 * outWidth};
vImage_Error err = vImageScale_ARGB8888(&inBuff, &outBuff, NULL, 0);
if (err != kvImageNoError) NSLog(@" error %ld", err);
现在我需要将outBuff
转换为CVPixelBufferRef
。
我认为我需要使用vImageBuffer_CopyToCVPixelBuffer
,但我不确定如何操作。
我的第一个尝试失败了,出现了EXC_BAD_ACCESS: CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
的错误。
CVPixelBufferRef pixelBuffer;
CVPixelBufferCreate(kCFAllocatorSystemDefault, 480, 480, kCVPixelFormatType_32BGRA, NULL, &pixelBuffer);
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
vImage_CGImageFormat format = {
.bitsPerComponent = 8,
.bitsPerPixel = 32,
.bitmapInfo = kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst, //BGRX8888
.colorSpace = NULL, //sRGB
};
vImageBuffer_CopyToCVPixelBuffer(&outBuff,
&format,
pixelBuffer,
NULL,
NULL,
kvImageNoFlags); // Here is the crash!
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
有任何想法吗?