WIP Add psnr function

Sparks_in_Blender_encode.py

@@ -179,6 +179,25 @@ def score_vmaf(outputfile: str, inputfile: str) -> dict[str, float]:
     return vmaf
 
 
+def score_psnr(outputfile: str, inputfile: str):
+    """
+    Calculate a file's MSE (mean-square error) using PSNR. A lower value is better
+
+    Parameters:
+    outputfile (str): Path to output file
+    inputfile (str): Path to input file
+
+    Return:
+    TBD
+    """
+    ff = ffmpy.FFmpeg(
+        inputs=OrderedDict([(outputfile, None), (inputfile, None)]),
+        outputs={"-": "-lavfi psnr=stats_file=psnr.log -f null"},
+    )
+
+    ff.run()
+
+
 if __name__ == "__main__":
     if not os.path.isdir("encoded"):
         os.mkdir("encoded")