Rework the x264 speedcontrol presets.

[nageru] / experiments / measure-x264.pl

diff --git a/experiments/measure-x264.pl b/experiments/measure-x264.pl
new file mode 100644 (file)
index 0000000..94f8715
--- /dev/null
+++ b/experiments/measure-x264.pl
@@ -0,0 +1,131 @@
+#! /usr/bin/perl
+
+#
+# A script to measure the quality and speed of the x264 presets used in speed control.
+#
+
+use strict;
+use warnings;
+use Time::HiRes;
+
+my $ssim_mode = 1;
+my $output_cpp = 1;
+my $flags = "--bitrate 4000 --frames 1000";
+my $override_flags = "--weightp 1 --mbtree --rc-lookahead 20";
+my $file = "elephants_dream_1080p24.y4m";  # https://media.xiph.org/video/derf/y4m/elephants_dream_1080p24.y4m
+
+if ($ssim_mode) {
+       # This can be run on a faster machine if you want to. It just measures SSIM;
+       # don't trust the timings, not even which modes are faster than others.
+       # The mode where $output_cpp=0 is just meant as a quick way to test new presets
+       # to see if they are good candidates.
+       $flags .= " --threads 40 --ssim";
+       $override_flags .= " --tune ssim";
+       open my $fh, "<", "presets.txt"
+               or die "presets.txt: $!";
+       my $preset_num = 0;
+       for my $preset (<$fh>) {
+               chomp $preset;
+               my ($ssim, $elapsed) = measure_preset($file, $flags, $override_flags, $preset);
+               if ($output_cpp) {
+                       output_cpp($file, $flags, $override_flags, $preset, $ssim, $preset_num++);
+               } else {
+                       printf "%sdb %.3f %s\n", $ssim, $elapsed, $preset;
+               }
+       }
+       close $fh;
+} else {
+       # Actual benchmarking.
+       my $repeat = 1;
+       $flags .= " --threads 4";
+       open my $fh, "<", "presets.txt"
+               or die "presets.txt: $!";
+       my $base = undef;
+       for my $preset (<$fh>) {
+               chomp $preset;
+               my $sum_elapsed = 0.0;
+               for my $i (1..$repeat) {
+                       my (undef, $elapsed) = measure_preset($file, $flags, $override_flags, $preset);
+                       $sum_elapsed += $elapsed;
+               }
+               my $avg = $sum_elapsed / $repeat;
+               $base //= $avg;
+               printf "%.3f %s\n", $avg / $base, $preset;
+       }
+       close $fh;
+}
+
+sub measure_preset {
+       my ($file, $flags, $override_flags, $preset) = @_;
+
+       my $now = [Time::HiRes::gettimeofday];
+       my $ssim;
+       open my $x264, "-|", "/usr/bin/x264 $flags $preset $override_flags -o /dev/null $file 2>&1";
+       for my $line (<$x264>) {
+               $line =~ /SSIM Mean.*\((\d+\.\d+)db\)/ and $ssim = $1;
+       }
+       close $x264;
+       my $elapsed = Time::HiRes::tv_interval($now);
+       return ($ssim, $elapsed);
+}
+
+sub output_cpp {
+       my ($file, $flags, $override_flags, $preset, $ssim, $preset_num) = @_;
+       unlink("tmp.h264");
+       system("/usr/bin/x264 $flags $preset $override_flags --frames 1 -o tmp.h264 $file >/dev/null 2>&1");
+       open my $fh, "<", "tmp.h264"
+               or die "tmp.h264: $!";
+       my $raw;
+       {
+               local $/ = undef;
+               $raw = <$fh>;
+       }
+       close $fh;
+
+       $raw =~ /subme=(\d+)/ or die;
+       my $subme = $1;
+
+       $raw =~ /me=(\S+)/ or die;
+       my $me = "X264_ME_" . uc($1);
+
+       $raw =~ /ref=(\d+)/ or die;
+       my $refs = $1;
+
+       $raw =~ /mixed_ref=(\d+)/ or die;
+       my $mix = $1;
+
+       $raw =~ /trellis=(\d+)/ or die;
+       my $trellis = $1;
+
+       $raw =~ /analyse=0x[0-9a-f]+:(0x[0-9a-f]+)/ or die;
+       my $partitions_hex = oct($1);
+       my @partitions = ();
+       push @partitions, 'I8' if ($partitions_hex & 0x0002);
+       push @partitions, 'I4' if ($partitions_hex & 0x0001);
+       push @partitions, 'P8' if ($partitions_hex & 0x0010);
+       push @partitions, 'B8' if ($partitions_hex & 0x0100);
+       push @partitions, 'P4' if ($partitions_hex & 0x0020);
+       my $partitions = join('|', @partitions);
+
+       $raw =~ /bframes=(\d+)/ or die;
+       my $bframes = $1;
+
+       my ($badapt, $direct);
+       if ($bframes > 0) {
+               $raw =~ /b_adapt=(\d+)/ or die;
+               $badapt = $1;
+               $raw =~ /direct=(\d+)/ or die;
+               $direct = $1;
+       } else {
+               $badapt = $direct = 0;
+       }
+
+       $raw =~ /me_range=(\d+)/ or die;
+       my $merange = $1;
+
+       print "\n";
+       print "\t// Preset $preset_num: ${ssim}db, $preset\n";
+       print "\t{ .time= 0.000, .subme=$subme, .me=$me, .refs=$refs, .mix=$mix, .trellis=$trellis, .partitions=$partitions, .badapt=$badapt, .bframes=$bframes, .direct=$direct, .merange=$merange },\n";
+
+#x264 - core 148 r2705 3f5ed56 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=34 lookahead_threads=5 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
+}