[MPlayer-users] MPlayer pnm frame extraction and psnr-video.sh

[David Thompson]

Hello:

I have a question regarding MPlayer and frame extraction - particularly
for use in performing a psnr comparison via pnmpsnr - as in the
psnr-video.sh script included in tools in the MPlayer project.

I have two types of videos I am hoping to compare to each other via a
psnr comparison of each to the uncompressed source: These are H.264 MOV
and VC-1 WMV files encoded at 1920x1080 from a 1920x1080 source.

The problem is that the PNM frames extracted by MPlayer from both the
source and the Quicktime H.264 files are 1920x1084 in size, so although
these compare fine, the frames extracted from the WMV VC-1 file are
exactly 1920x1080.  Therefore, since they have a different number of
rows, they can't be compared via pnmpsnr.

Can anyone explain to me why the pnm frames extracted from the
uncompressed and quicktime videos are 1920x1084 in size, when the
uncompressed source in indeed 1920x1080 and the quicktime videos were
transcoded at 1920x1080 frame resolution?

Also, I would greatly appreciate any advice on how to possibly get
around this issue!

Cheers,

David