PSNR measurement on CUDA H.264 Encoder

I have implemented a video streaming application using CUDA Video Encoder/Decoder API. To measure the video quality at the encoder side, I need to read the PSNR measurements.Inside “VideoEncoder” class, there is a variable called “m_pSNRData”. I also enabled “pParams->measure_psnr = 1;” but I cannot access the PSNR values. This measurement is very important for me to assess the system in terms of objective visual quality.

Thanks a lot for your help