Hi,
In the patch, it demonstrates mapping NvBuffer to cv::Mat in RGBA, convert to the other cv::Mat in BGR and render through cv::imshow():
NVBuffer (FD) to opencv Mat - #6 by DaneLLL
If you would like to use NvEglRenderer, would need to convert the data in cv::Mat in BGR back to the cv::Mat in RGBA, call NvBufferMemSyncForDevice(), and render the NvBuffer. It is uncertain whether this has better performance than cv::imshow(). Would be great if you can give it a try and share us the result.