4 # A script to measure the quality and speed of the x264 presets used in speed control.
13 my $flags = "--bitrate 4000 --frames 1000";
14 my $override_flags = "--weightp 1 --mbtree --rc-lookahead 20 --b-adapt 1 --bframes 3";
15 my $file = "elephants_dream_1080p24.y4m"; # https://media.xiph.org/video/derf/y4m/elephants_dream_1080p24.y4m
18 # This can be run on a faster machine if you want to. It just measures SSIM;
19 # don't trust the timings, not even which modes are faster than others.
20 # The mode where $output_cpp=0 is just meant as a quick way to test new presets
21 # to see if they are good candidates.
22 $flags .= " --threads 40 --ssim";
23 $override_flags .= " --tune ssim";
24 open my $fh, "<", "presets.txt"
25 or die "presets.txt: $!";
27 for my $preset (<$fh>) {
29 my ($ssim, $elapsed) = measure_preset($file, $flags, $override_flags, $preset);
31 output_cpp($file, $flags, $override_flags, $preset, $ssim, $preset_num++);
33 printf "%sdb %.3f %s\n", $ssim, $elapsed, $preset;
38 # Actual benchmarking.
40 $flags .= " --threads 4";
41 open my $fh, "<", "presets.txt"
42 or die "presets.txt: $!";
44 for my $preset (<$fh>) {
46 my $sum_elapsed = 0.0;
47 for my $i (1..$repeat) {
48 my (undef, $elapsed) = measure_preset($file, $flags, $override_flags, $preset);
49 $sum_elapsed += $elapsed;
51 my $avg = $sum_elapsed / $repeat;
53 printf "%.3f %s\n", $avg / $base, $preset;
59 my ($file, $flags, $override_flags, $preset) = @_;
61 my $now = [Time::HiRes::gettimeofday];
63 open my $x264, "-|", "/usr/bin/x264 $flags $preset $override_flags -o /dev/null $file 2>&1";
64 for my $line (<$x264>) {
65 $line =~ /SSIM Mean.*\(\s*(\d+\.\d+)db\)/ and $ssim = $1;
68 my $elapsed = Time::HiRes::tv_interval($now);
69 return ($ssim, $elapsed);
73 my ($file, $flags, $override_flags, $preset, $ssim, $preset_num) = @_;
75 system("/usr/bin/x264 $flags $preset $override_flags --frames 1 -o tmp.h264 $file >/dev/null 2>&1");
76 open my $fh, "<", "tmp.h264"
77 or die "tmp.h264: $!";
85 $raw =~ /subme=(\d+)/ or die;
88 $raw =~ /me=(\S+)/ or die;
89 my $me = "X264_ME_" . uc($1);
91 $raw =~ /ref=(\d+)/ or die;
94 $raw =~ /mixed_ref=(\d+)/ or die;
97 $raw =~ /trellis=(\d+)/ or die;
100 $raw =~ /analyse=0x[0-9a-f]+:(0x[0-9a-f]+)/ or die;
101 my $partitions_hex = oct($1);
103 push @partitions, 'I8' if ($partitions_hex & 0x0002);
104 push @partitions, 'I4' if ($partitions_hex & 0x0001);
105 push @partitions, 'P8' if ($partitions_hex & 0x0010);
106 push @partitions, 'B8' if ($partitions_hex & 0x0100);
107 push @partitions, 'P4' if ($partitions_hex & 0x0020);
108 my $partitions = join('|', @partitions);
110 $raw =~ /direct=(\d+)/ or die;
113 $raw =~ /me_range=(\d+)/ or die;
117 print "\t// Preset $preset_num: ${ssim}db, $preset\n";
118 print "\t{ .time= 0.000, .subme=$subme, .me=$me, .refs=$refs, .mix=$mix, .trellis=$trellis, .partitions=$partitions, .direct=$direct, .merange=$merange },\n";
120 #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