Compressibility test perl script

[echo]

There was a perl script that evade had made in this thread. (http://forum.doom9.org/showthread.php?t=73124) I've been using it a lot but unfortunately I've lost it somewhere and the link that evade had provided doesn't work anymore. Does anyone have it? (are you still around evade?)

Thanks.

[Sco0by]

Hi everybody!
Here you go, I added some features, thanks evade :D :


#!/usr/bin/perl # Supply one argument a quoted string to complete the mencoder comand e.g. "-vf crop=720:352:0:60 stream.dump"

# Uncomment the following line for an XviD-Compress-Test:
$encoptions="-ovc xvid -xvidencopts fixed_quant=2:trellis:quant_type=mpeg:qpel:chroma_me:max_bframes=3:vhq=1:min_iquant=1:max_iquant=31:min_pquant=1:max_pquant=31:min_bquant=1:max_bquant=31";
# Uncomment for an x264-Compress-Test:
#$encoptions="-ovc x264 -x264encopts qp_constant=19:cabac:deblock:frameref=3:bframes=2:b_adapt:qp_step=4:4x4mv:weight_b:chroma_me";

$second=0;
$cnt=0;
$tk=0;
$k=1;
until ( $k == "" ) { $k=`mencoder -nosound $encoptions -o /dev/null -ss ${second} -endpos 00:03 $ARGV[0] 2> /dev/null | grep 'Video stream'`;
$k =~ s/Video stream..//g;
$k =~ s/\..*\n//g;
$tk=${tk}+${k};
$cnt++;
$second=${second}+60;
printf "\rPosition: %02d:%02d", ($second/60), $second%60; }
$cnt--;
$ak=${tk}/${cnt};
$tb=${ak}*2/3;
print "\nAverage kbits/s = ${ak}. Go for ${tb}\n";


Save this to an file (e.g. comptest.pl) and use it like:
perl comptest.pl "-vf pp=de,crop=688:560:16:10 myTestFile.vob"

This compresses 3 seconds in intervals of 1 minute (=5% of the movie) using mencoder. Evades original used 6 seconds every 2 minutes, but some testing showed me, that the results using 3/60 sec are closer to those mencoder gives as average bitrate encoding the whole movie at fixed_quant=2.
Surprisingly, the "GKnot Windows-method" (14 out of 280 frames) gave a very high deviation from the value mencoder prints for the whole movie.

You can also do a x264-compress-test by using the corresponding settings (uncomment the line with $encoptions=... for x264).
Both, XviD and x264-settings, are from the "Doom9 Windows guides".

Please make your suggestions (settings, need and purpose of x264-compress-test, ...)

[echo]

Thank you so much! I have to say all these changes are very welcome! :)

[six6]

I agree, these changes are welcome. I will incorporate some incarnation of this into bitterbpp (http://www.derekfrye.com/bitterbpp), if it's under the GPL.

[evade]

Yeah: free as in free speech, Include away.