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Brooke Vibber 2023-01-14 17:20:35 -08:00
commit 2a55fc989f
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163
pack-vid Executable file
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#!/usr/bin/env php
<?php
// Squishes given video input into 4000kb .mp4
// Crops to 16:9
// Picks bitrate to match
// Picks resolution based on bitrate target
// 2-pass encoding with libx264 veryslow
$args = $_SERVER['argv'];
$self = array_shift( $args );
if ( count ( $args ) < 2 ) {
die( "Usage: pack-vid.php <srcfile.mp4> <destfile.mp4>\n" );
}
[ $src, $dest ] = $args;
convert( $src, $dest );
exit(0);
//
function run( $cmd, $args ) {
$commandLine = implode( ' ',
array_merge(
[ escapeshellcmd( $cmd ) ],
array_map( 'escapeshellarg', $args )
)
);
echo "$commandLine\n";
$output = shell_exec( $commandLine );
if ( $output === false ) {
throw new Error( "Failed to run $cmd" );
}
return $output;
}
function ffprobe( $path ) {
$output = run( 'ffprobe', [
'-hide_banner',
'-show_format',
'-show_streams',
'-print_format',
'json',
'--',
$path
] );
$data = json_decode( $output );
if ( $data === null ) {
throw new Error( "Failed to read JSON from ffprobe: $output" );
}
return $data;
}
function evenize( $n ) {
$n = ceil( $n );
if ( $n & 1 ) {
$n++;
}
return $n;
}
function convert( $src, $dest ) {
$maxBits = 4000 * 1000 * 8; // fit in 4Mb
$maxBits = $maxBits * 7 / 8; // leave some headroom
$probe = ffprobe( $src );
$videoTracks = array_filter( $probe->streams, function ( $stream ) {
return $stream->codec_type === 'video';
} );
$track = $videoTracks[0];
$duration = floatval( $track->duration );
$width = $track->width;
$height = $track->height;
$hdr = $track->color_primaries === 'bt2020';
$keyframeInt = ceil( $duration * 60 );
$bitrate = floor( $maxBits / $duration );
$mbits = 1000 * 1000;
if ( $bitrate < 2 * $mbits ) {
$cropWidth = 854;
$scaleHeight = 480;
} else if ( $bitrate <= 4 * $mbits ) {
$cropWidth = 1280;
$scaleHeight = 720;
} else {
$cropWidth = 1920;
$scaleHeight = 1080;
}
$scaleWidth = evenize( $width * $scaleHeight / $height );
$filters = [ "scale=w=$scaleWidth:h=$scaleHeight" ];
if ( $hdr ) {
$filters[] = "zscale=t=linear:p=bt709";
$filters[] = "tonemap=hable";
$filters[] = "zscale=t=bt709:m=bt709:r=full";
}
$filters[] = "format=yuv420p";
$filters[] = "crop=w=$cropWidth";
$vf = implode( ',', $filters );
run( 'ffmpeg', [
'-i', $src,
'-f', 'null',
'-vf', $vf,
'-c:v', 'libx264',
'-b:v', $bitrate,
'-preset', 'veryslow',
'-pass', '1',
'-g', $keyframeInt,
'-an',
'-y', '/dev/null'
] );
run( 'ffmpeg', [
'-i', $src,
'-vf', $vf,
'-c:v', 'libx264',
'-b:v', $bitrate,
'-preset', 'veryslow',
'-pass', '2',
'-g', $keyframeInt,
'-an',
'-y', $dest
] );
}
/*
# <18s
ffmpeg \
-i "yikes.mp4" \
-f null \
-vf "zscale=t=linear:p=bt709,\
tonemap=hable,\
zscale=w=1146:h=480:t=bt709:m=bt709:r=full,format=yuv420p,\
crop=w=854" \
-vcodec libx264 \
-b:v 1250k \
-preset veryslow \
-pass 1 \
-g 1080 \
-an \
-y /dev/null && \
ffmpeg \
-i "yikes.mp4" \
-vf "zscale=t=linear:p=bt709,\
tonemap=hable,\
zscale=w=1146:h=480:t=bt709:m=bt709:r=full,format=yuv420p,\
crop=w=854" \
-vcodec libx264 \
-b:v 1250k \
-pass 2 \
-preset veryslow \
-g 1080 \
-ab 96k \
-movflags +faststart \
-y yikes-small-compat.mp4
*/