[MEncoder-users] Relation between psnr_*.log and PSNR:

[Mario Valle]

Can someone enlight me on the psnr values printed on stdout and the ones contained in the 
psnr_*.log file?

After running mencoder I have for example the following values printed:
PSNR: Y:30.47, Cb:32.88, Cr:35.56, All:31.36

Instead averaging the corresponding columns from the psnr_*.log file gives:

         31.21     33.41     36.10      32.06


I use the PSNR all value just to see the effect of the various parameters on encoding
so the absolute value is not important, but the relative change yes. So I'm wondering if 
the difference is due only to rounding errors or I'm doing something stupid.

Thanks for your help!
				mario


-- 
Ing. Mario Valle
Visualization Group                              | http://www.cscs.ch/~mvalle
Swiss National Supercomputing Centre (CSCS)      | Tel:  +41 (91) 610.82.60
v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax:  +41 (91) 610.82.82