When the MTS4EA performs a PSNR fidelity analysis between an encoded file and a raw YUV source file, it computes the PSNR using either the full signal range or the ITU-R BT.601 signal range (user's choice) on a per-frame basis using the formula: PSNR = 20*log( peak signal / RMS error ) The mean average of each frame's individual PSNR value is then taken and given as the overall PSNR value for the stream. The fidelity analysis algorithm is discussed in more detail in the MTS4EA user manual starting on page 6-163.