From 96f4cf2f72a4d56cbb0b0f35a24fba90a01eea2f Mon Sep 17 00:00:00 2001
From: Brooke Vibber <bvibber@pobox.com>
Date: Wed, 1 Oct 2025 12:44:09 -0700
Subject: [PATCH] retooling a bit

* allow setting vcodec
* remove the min/max bitrate caps
* allow a non-square-output with --stretch
* cleanup bitrate setup
* don't force audio channels
* allow setting audio sample rate
* don't force preset
---
 pack-vid | 226 ++++++++++++++++++++++++++-----------------------------
 1 file changed, 106 insertions(+), 120 deletions(-)

diff --git a/pack-vid b/pack-vid
index 2ad6b7d..7ca7fa8 100755
--- a/pack-vid
+++ b/pack-vid
@@ -21,10 +21,11 @@ $options = [
     'letterbox' => false,
     'no-audio' => false,
     'audio-bitrate' => 96000,
-    'audio-channels' => 2,
+    'audio-rate' => false,
+    'audio-channels' => false,
     'exposure' => '0', // stops
     'peak' => '1000', // '10000' is max
-    'preset' => 'medium',
+    'preset' => false,
     'fps' => '60',
     'size' => $maxBytes,
     'quality' => 1.0,
@@ -41,6 +42,8 @@ $options = [
     'crop-top' => false,
     'tonemap' => 'hable',
     'color-temperature' => false,
+    'vcodec' => 'libx264',
+    'stretch' => false,
 ];
 
 while ( count( $args ) > 0 && substr( $args[0], 0, 2 ) == '--' ) {
@@ -153,8 +156,6 @@ function extractTracks( $streams, $type ) {
 }
 
 function convert( $src, $dest, $options ) {
-    $maxBits = 8 * sizify( $options['size'] );
-
     $probe = ffprobe( $src );
 
     $videoTracks = extractTracks( $probe->streams, 'video' );
@@ -198,9 +199,14 @@ function convert( $src, $dest, $options ) {
         $keyframeInt = intval( ceil( $duration * 60 ) );
     }
 
-    $bitrate = floor( $maxBits / $duration );
     if ( $options['bitrate'] ) {
         $bitrate = sizify( $options['bitrate'] );
+    } else if ( $options[ 'size' ] ) {
+        $maxBits = 8 * sizify( $options['size'] );
+        $bitrate = floor( $maxBits / $duration );
+    } else {
+        // Calculate a target bitrate from the size later
+        $bitrate = null;
     }
 
 
@@ -208,127 +214,93 @@ function convert( $src, $dest, $options ) {
         $audio = [ '-an' ];
     } else {
         $audioBitrate = $options[ 'audio-bitrate' ];
-        $audioChannels = $options[ 'audio-channels' ];
         $audio = [
-            '-ac', $audioChannels,
             '-b:a', $audioBitrate,
         ];
+        if ( $options['audio-channels'] ) {
+            $audio[] = '-ac';
+            $audio[] = $options[ 'audio-channels' ];
+        }
+        if ( $options[ 'audio-rate' ] ) {
+            $audio[] = '-ar';
+            $audio[] = $options[ 'audio-rate' ];
+        }
         $bitrate -= $audioBitrate;
     }
 
-    $bitrate = max( $bitrate, 16000 );
-    $mbits = 1000 * 1000;
-    $base = intval( $mbits * floatval( $options['quality'] ) );
-    if ( $bitrate < 0.125 * $base || $height < 144 ) {
-        $frameWidth = 256;
-        $frameHeight = 144;
-        $bitrate = min( $bitrate, $base * 0.25 );
-    } elseif ( $bitrate < 0.25 * $base || $height < 180 ) {
-        $frameWidth = 320;
-        $frameHeight = 180;
-        $bitrate = min( $bitrate, $base * 0.5 );
-    } elseif ( $bitrate < 0.5 * $base || $height < 288 ) {
-        $frameWidth = 512;
-        $frameHeight = 288;
-        $bitrate = min( $bitrate, $base * 0.5 );
-    } elseif ( $bitrate < 1 * $base || $height < 480 ) {
-        $frameWidth = 640;
-        $frameHeight = 360;
-        $bitrate = min( $bitrate, $base );
-    } elseif ( $bitrate < 2 * $base || $height < 540) {
-        $frameWidth = 854;
-        $frameHeight = 480;
-        $bitrate = min( $bitrate, $base * 2 );
-    } elseif ( $bitrate < 2.5 * $base || $height < 720) {
-        $frameWidth = 960;
-        $frameHeight = 540;
-        $bitrate = min( $bitrate, $base * 2.5 );
-    } elseif ( $bitrate < 4 * $base || $height < 1080) {
-        $frameWidth = 1280;
-        $frameHeight = 720;
-        $bitrate = min( $bitrate, $base * 4 );
-    } elseif ( $bitrate < 8 * $base || $height < 1440) {
-        $frameWidth = 1920;
-        $frameHeight = 1080;
-        $bitrate = min( $bitrate, $base * 8 );
-    } elseif ( $bitrate < 16 * $base || $height < 2160) {
-        $frameWidth = 2560;
-        $frameHeight = 1440;
-        $bitrate = min( $bitrate, $base * 16 );
+    if ( $options[ 'width' ] && $options[ 'height' ] ) {
+        // Use exact given dimensions.
+        $frameWidth = intval( $options[ 'width' ] );
+        $frameHeight = intval( $options[ 'height' ] );
     } else {
-        $frameWidth = 3840;
-        $frameHeight = 2160;
-        $bitrate = min( $bitrate, $base * 32 );
+        // Select target resolution from the target bitrate...
+        if ( !$bitrate ) {
+            // If we didn't get given one, default to 5Mbits 1080HD
+            $bitrate = 5000000;
+        }
+        $mbits = 1000 * 1000;
+        $base = intval( $mbits * floatval( $options['quality'] ) );
+        if ( $bitrate < 0.125 * $base || $height < 144 ) {
+            $frameWidth = 256;
+            $frameHeight = 144;
+        } elseif ( $bitrate < 0.25 * $base || $height < 180 ) {
+            $frameWidth = 320;
+            $frameHeight = 180;
+        } elseif ( $bitrate < 0.5 * $base || $height < 288 ) {
+            $frameWidth = 512;
+            $frameHeight = 288;
+        } elseif ( $bitrate < 1 * $base || $height < 480 ) {
+            $frameWidth = 640;
+            $frameHeight = 360;
+        } elseif ( $bitrate < 2 * $base || $height < 540) {
+            $frameWidth = 854;
+            $frameHeight = 480;
+        } elseif ( $bitrate < 2.5 * $base || $height < 720) {
+            $frameWidth = 960;
+            $frameHeight = 540;
+        } elseif ( $bitrate < 4 * $base || $height < 1080) {
+            $frameWidth = 1280;
+            $frameHeight = 720;
+        } elseif ( $bitrate < 8 * $base || $height < 1440) {
+            $frameWidth = 1920;
+            $frameHeight = 1080;
+        } elseif ( $bitrate < 16 * $base || $height < 2160) {
+            $frameWidth = 2560;
+            $frameHeight = 1440;
+        } else {
+            $frameWidth = 3840;
+            $frameHeight = 2160;
+        }
     }
 
     $aspect = $width / $height;
     $pixels = $width * $height;
 
-    // canonical min rate is 0.125 megabit at 144p
-    $bitrate = max( $bitrate, 0.125 * $base );
-
-    /*
-    $minWidth = 640;
-    $minHeight = 360;
-
-    $baseWidth = 854;
-    $baseHeight = 480;
-    $pixelsPerBit = ( $baseWidth * $baseHeight ) / $base;
-
-    $maxWidth = 1920;
-    $maxHeight = 1080;
-    $maxrate = $base * ( $maxWidth * $maxHeight ) / ( $baseWidth * $baseHeight );
-
-    $pixels = $bitrate * $pixelsPerBit;
-    $frameHeight = evenize( sqrt( $pixels / $aspect ) );
-    $frameWidth = evenize( $frameHeight * $aspect );
-
-    if ( $aspect > 16 / 9 ) {
-        if ( $frameWidth < $minWidth ) {
-            $frameWidth = $minWidth;
-            $frameHeight = evenize( $frameWidth / $aspect );
-        } elseif ( $frameWidth > $maxWidth ) {
-            $frameWidth = $maxWidth;
-            $frameHeight = evenize( $frameWidth / $aspect );
-            $bitrate = min( $bitrate, $maxrate );
-        }
+    if ( $options[ 'stretch' ] ) {
+        // Use this option when making non-square output
+        $scaleWidth = $frameWidth;
+        $scaleHeight = $frameHeight;
     } else {
-        if ( $frameHeight < $minHeight ) {
-            $frameHeight = $minHeight;
-            $frameWidth = evenize( $frameHeight * $aspect );
-        } elseif ( $frameWidth > $maxWidth ) {
-            $frameHeight = $maxHeight;
-            $frameWidth = evenize( $frameHeight * $aspect );
-            $bitrate = min( $bitrate, $maxrate );
-        }
-    }
-    */
-
-    if ( $options['width'] ) {
-        $frameWidth = intval( $options['width'] );
-    }
-    if ( $options['height'] ) {
-        $frameHeight = intval( $options['height'] );
-    }
-
-    $wide = $aspect > ( $frameWidth / $frameHeight );
-    $crop = boolval( $options['crop'] );
-    $letterbox = boolval( $options['letterbox'] );
-    if ( $crop ) {
-        if ( $wide ) {
-            $scaleHeight = $frameHeight;
-            $scaleWidth = evenize( $frameHeight * $aspect );
+        // Assumes square pixels
+        $wide = $aspect > ( $frameWidth / $frameHeight );
+        $crop = boolval( $options['crop'] );
+        $letterbox = boolval( $options['letterbox'] );
+        if ( $crop ) {
+            if ( $wide ) {
+                $scaleHeight = $frameHeight;
+                $scaleWidth = evenize( $frameHeight * $aspect );
+            } else {
+                $scaleWidth = $frameWidth;
+                $scaleHeight = evenize( $frameWidth / $aspect );
+            }
         } else {
-            $scaleWidth = $frameWidth;
-            $scaleHeight = evenize( $frameWidth / $aspect );
-        }
-    } else {
-        if ( $wide ) {
-            $scaleWidth = $frameWidth;
-            $scaleHeight = evenize( $frameWidth / $aspect );
-        } else {
-            $scaleHeight = $frameHeight;
-            $scaleWidth = evenize( $frameHeight * $aspect );
+            if ( $wide ) {
+                $scaleWidth = $frameWidth;
+                $scaleHeight = evenize( $frameWidth / $aspect );
+            } else {
+                $scaleHeight = $frameHeight;
+                $scaleWidth = evenize( $frameHeight * $aspect );
+            }
         }
     }
 
@@ -376,7 +348,22 @@ function convert( $src, $dest, $options ) {
 
     $fps = $options['fps'];
 
-    $preset = $options['preset'];
+    if ( $options['preset'] ) {
+        $preset = [ '-preset', $options[ 'preset' ] ];
+    } else {
+        $preset = [];
+    }
+
+    $extension = pathinfo( $dest )[ 'extension' ];
+    if ( $extension === 'mp4' || $extension === 'mov' ) {
+        $format = [ '-movflags', '+faststart' ];
+    } else if ( $extension === 'webm' || $extension === 'mkv' ) {
+        $format = [ '-cues_to_front', 1 ];
+    } else {
+        $format = [];
+    }
+
+    $vcodec = $options['vcodec'];
 
     $tempPrefix = 'pack-vid-passlog' . rand(0,1 << 31);
     $passlog = tempnam( '.', $tempPrefix );
@@ -386,13 +373,13 @@ function convert( $src, $dest, $options ) {
             '-f', 'mp4',
             '-fpsmax', $fps,
             '-vf', $vf,
-            '-c:v', 'libx264',
+            '-c:v', $vcodec,
             '-b:v', $bitrate,
-            '-preset', $preset,
+        ], $preset, [
             '-pass', '1',
             '-passlogfile', $passlog,
             '-g', $keyframeInt,
-        ], $audio, [
+            '-an',
             '-y', '/dev/null'
         ] )
     );
@@ -401,14 +388,13 @@ function convert( $src, $dest, $options ) {
             '-i', $src,
             '-vf', $vf,
             '-fpsmax', $fps,
-            '-c:v', 'libx264',
+            '-c:v', $vcodec,
             '-b:v', $bitrate,
-            '-preset', $preset,
+        ], $preset, [
             '-pass', '2',
             '-passlogfile', $passlog,
             '-g', $keyframeInt,
-        ], $audio, [
-            '-movflags', '+faststart',
+        ], $audio, $format, [
             '-y', $dest
         ] )
     );