[MEncoder-users] [Script] PSNR between two video files

[Matthias Wieser]

Hi,

I have created a script (called psnr-video.sh) to calculate the PSNR 
between two existing video files. The PSNR is calculated frame by frame. 
Additionally an overall PSNR is calculated.

The output file can be used for plots of the frame by frame PSNR.

"What's the purpose of this script, as there is already the mencoder 
option 'psnr'"?

mencoder [...]:psnr only shows the psnr of the video codec. Video filters 
like scaling, denoise3d, pp=fd cannot be tested with this option.

psnr-video.sh can be used to

* compare different softwarescalers (should I use -sws 1 or -sws 2)
* compare different resolutions (is it better to scale down to 640x360 or
   to 560x320)
* compare different deinterlacers
* compare different video codecs
* compare video filters (is it better to use -vf hqdn3d or
   lavcopts:nr=400)
* [...]

Example:
./psnr-video.sh ./orig.avi ./test.avi 247

Creates a file psnr.dat with the following content:

File;Y;Cb;Cr
00000001.ppm;34.23;39.54;40.06;35.426
00000002.ppm;33.03;38.71;39.26;34.271
00000003.ppm;33.45;38.91;39.28;34.655
00000004.ppm;32.72;38.69;38.85;33.972
[...]
00000247.ppm;35.55;40.84;42.15;36.785
PSNR:;35.9887

-------

Usage: psnr-video.sh <file1> <file2> [<frames>] [<options1>] [<options2>]

 <file1> and <file2> are the video files for which the PSNR should be
                     calculated.
 [<frames>]          is the number of frames to process, starting from
                     frame 1.
 [<options1>]        are additional MPlayer options for <file1>
 [<options2>]        are additional MPlayer options for <file2>

 Be aware that psnr-video.sh needs a lot of temporal space inside /temp/.

-------

Comments?

If you find it usefull you may add it to [CVS]main/TOOLS/

Regards,
  Matthias
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