get buffer from CMSampleBufferRef

从

CMSampleBufferRef获得数据buffer。

NSData* imageToBuffer( CMSampleBufferRef source) {
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(source);
CVPixelBufferLockBaseAddress(imageBuffer,0);

size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
void *src_buff = CVPixelBufferGetBaseAddress(imageBuffer);

NSData *data = [NSData dataWithBytes:src_buff length:bytesPerRow * height];

CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
return [data autorelease];
}