View source for Compare

{{Template:FuncDef|Compare(clip_filtered ''clip'', clip_original ''clip'', string ''channels'', string ''logfile'', bool ''show_graph'')}}

This filter compares the original clip "clip_original" and its filtered version "clip_filtered". The filtered version will be returned with the results of the comparison. Per frame the Mean Absolute Difference, Mean Difference and Peak signal-to-noise ratio ([[PSNR]]) is given, as well as the min (minimum), avg (average) and max (maximum) PSNR up to that frame (calculated frame-wise). Starting from v2.53, the 'Overall PSNR' (calculated over all pixels in all frames) is also shown on the output clip.

The ''channels'' (default "") string is a combination of R,G,B [,A] or Y,U,V, depending on the source clips. If it is empty (default), it means either "[[YUV]]" when the input clips are YCbCr or "[[RGB]]" when in the input clips are RGB.

If ''show_graph'' (default true) is true then Marc's PSNR graph is also drawn on it. 

If a logfile is specified, the results will be written to a file by this name and not drawn on the clip. It is much faster if you need to compare a lot of frames.

'''Examples:'''

 # displays differences on screen:
 Compare(clip1, clip2)

 # for creating a log file:
 Compare(clip1, clip2, "", "compare.log")

 # will only compare chroma channels of YUY2 clips:
 Compare(clip1, clip2, "UV")


'''Changes:'''
{| border="1"
|- 
| v2.58
| Added YV12 support.
|}

[[Category:Internal filters]]