[MPlayer-dev-eng] [PATCH] countquant.pl

[Loren Merritt]

On Mon, 20 Sep 2004, Diego Biurrun wrote:

> Loren Merritt writes:
>>
>> 1) See those entries in divx2pass.log that look like "q:236"?
>> Those are lagrange multipliers, and 236 is the lambda used then you
>> select vqscale=2. (That space used to contain quantizers, which is why
>> it's labelled "q" and why countquant.pl is obsolete.)
>
> Does it really  have no use at all anymore?  I'll remove it then.

I didn't say it was useless, only out of date.

Here's the script I use, if you want to update it.
(works on psnr.log, not divx2pass.log)

--Loren Merritt
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#!/usr/bin/env perl
# counts quantizer and psnr statistics from the log generated by mencoder/lavc
$^W=1;
use strict;

my $usage = "usage:  countquant.pl psnr_??????.log [...]\n";
if(grep {$_ eq '-h'} @ARGV) {
    die $usage;
}
# show $mult fractional qp partitions.
# (framewise qp may be fractional with qprd or *_mask).
my $mult = 1;
if(@ARGV and $ARGV[0] =~ /^-(\d+)$/) {
    $mult = $1;
    shift @ARGV;
}

sub mse2psnr($) {
    my $d = shift;
    return "inf" if !$d;
    return -10*log($d)/log(10);
}
sub psnr2mse($) {
    my $p = shift;
    return 0 if $p eq "inf";
    return 10**(-$p/10);
}

sub proc_file($) {
    my $fh = shift;
    my(%count, @qp_count, %qp_avg, %mse, $size);
    %count = %qp_avg = (I=>0, P=>0, B=>0, A=>0);
    @qp_count = (0) x (31*$mult);

    # parse input file
    while(<$fh>) {
        /^\s*(\d+),\s+(\d+\.\d+),\s+(\d+), (\S+), (\S+), (\S+), (\S+) ([IPB])/ or next;
        $count{$8} ++;
        $qp_count[int($2*$mult+.5)] ++;
        $qp_avg{$8} += $2;
        $size += $3;
        $mse{$8}{Y} += psnr2mse($4);
        $mse{$8}{U} += psnr2mse($5);
        $mse{$8}{V} += psnr2mse($6);
    }
    close($fh);

    # compute stat averages
    foreach my $t (qw(I P B)) {
        $count{$t} or next;
        $count{A} += $count{$t};
        $qp_avg{A} += $qp_avg{$t};
        $mse{$t}{A} = (4*$mse{$t}{Y} + $mse{$t}{U} + $mse{$t}{V}) / 6;
        for(qw(Y U V A)) {
            $mse{A}{$_} += $mse{$t}{$_};
        }
    }
    foreach my $t (qw(I P B A)) {
        $count{$t} or next;
        $qp_avg{$t} /= $count{$t};
        for(qw(Y U V A)) {
            $mse{$t}{$_} /= $count{$t};
        }
    }

    if(!$count{A}) {
        warn "no frames found\n";
        die $usage;
    }

    # print stats
    for(0 .. 31*$mult) {
        next unless $qp_count[$_] or ($_>0 and $qp_count[$_-1] and $qp_count[$_+1]);
        printf( ($mult == 1 ? "q%2d" : "q%4.1f") . ": %6d (%4.1f%%)\n",
                $_/$mult, $qp_count[$_], 100*$qp_count[$_]/$count{A} );
    }
    print "\n";

    my $count_digits = int(log($count{A}+1)/log(10))+2;
    $count_digits += 2 if $mult>1;
    foreach my $t (qw(I P B)) {
        printf "$t:   %${count_digits}d (%4.1f%%)  q:%5.2f  psnr: %5.2f\n",
               $count{$t}, 100*$count{$t}/$count{A}, $qp_avg{$t}, mse2psnr($mse{$t}{A});
    }
    printf "All: %${count_digits}d          q:%5.2f  psnr: %5.2f (Y:%5.2f Cb:%5.2f Cr:%5.2f)\n",
           $count{A}, $qp_avg{A}, (map {mse2psnr($mse{A}{$_})} qw(A Y U V));
    print "\n";
    
    printf "total size: %d = %.1f MiB = %.2f kbps @ 23.976 fps\n",
        $size, $size/2**20, (8*24/1001)*$size/$count{A};
}

# decompress a file if it's compressed, otherwise just open it
sub openz($) {
    my $fn = shift;
    my $fh;
    if($fn =~ /\.bz2$/) {
        open $fh, "-|", "bzcat", $fn
            or warn "can't bunzip2 '$fn': $!\n" and return undef;
    } elsif($fn =~ /\.gz$/) {
        open $fh, "-|", "zcat", $fn
            or warn "can't zcat '$fn': $!\n" and return undef;
    } else {
        open $fh, "<", $fn
            or warn "can't open '$fn': $!\n" and return undef;
    }
    return $fh;
}

if(@ARGV) {
    foreach(@ARGV) {
        print "\n$_:\n" if @ARGV > 1;
        proc_file(openz($_)||next);
    }
} else {
    proc_file(*STDIN);
}