Doom9's Forum - View Single Post - SSIM 0.24, an objective video quality metric

DDogg · 11th September 2003, 17:16

Well it is symmetrical if you don't screw up and get a framecount unbalance like I did

One thing for mpg2 users to be careful of is the the two samples must be the exact same frame count (obviously), however, when using a mpv of a verified 5001 framecount, I noticed when using dvd2avi to create the d2v used in mpeg2source("b.d2v") that the framecount became 4998. So it is best to use the trim statement of a slightly smaller value to actually insure the exact frame count and double check it in VDub using file/information. I used mpeg2source("b.d2v").trim(0,4499) to give me an exact 4500 frames.

I noticed lafungus has updated ssim to catch this framecount unbalance in the newer version he posted so maybe it will not slip past others like it did for me using the first version.

Sidenote:I was gently pointed to the heavy thread in the dvd2avi forum dealing with this very subject where DG is putting in an enormous amount of effort dealing with framecount errors between dvd2avi and mpeg2dec. I don't read that forum much so I was unaware. Thanks!

11th September 2003, 17:16	#10 \| Link
DDogg Retired, but still around Join Date: Oct 2001 Location: Lone Star Posts: 3,058	Well it is symmetrical if you don't screw up and get a framecount unbalance like I did One thing for mpg2 users to be careful of is the the two samples must be the exact same frame count (obviously), however, when using a mpv of a verified 5001 framecount, I noticed when using dvd2avi to create the d2v used in mpeg2source("b.d2v") that the framecount became 4998. So it is best to use the trim statement of a slightly smaller value to actually insure the exact frame count and double check it in VDub using file/information. I used mpeg2source("b.d2v").trim(0,4499) to give me an exact 4500 frames. I noticed lafungus has updated ssim to catch this framecount unbalance in the newer version he posted so maybe it will not slip past others like it did for me using the first version. Sidenote:I was gently pointed to the heavy thread in the dvd2avi forum dealing with this very subject where DG is putting in an enormous amount of effort dealing with framecount errors between dvd2avi and mpeg2dec. I don't read that forum much so I was unaware. Thanks! Last edited by DDogg; 11th September 2003 at 20:29.