diff --git a/pack-vid b/pack-vid
index 6d7a6a7..6560ce2 100755
--- a/pack-vid
+++ b/pack-vid
@@ -22,6 +22,7 @@ $options = [
     'peak' => '10000',
     'fps' => '60',
     'size' => $maxBytes,
+    'quality' => 0.75,
 ];
 
 while ( count( $args ) > 0 && substr( $args[0], 0, 2 ) == '--' ) {
@@ -44,7 +45,8 @@ if ( count ( $args ) < 2 ) {
         "  --exposure=n   adjust exposure\n" .
         "  --peak=n       set HDR peak nits\n" .
         "  --fps=n        frame rate limit\n" .
-        "  --size=n       target file size in bytes (default 3.5M)\n"
+        "  --size=n       target file size in bytes (default 3.5M)\n" .
+        "  --quality=n    fraction of base bitrate to break on (deafult 0.75)\n"
     );
 }
 [ $src, $dest ] = $args;
@@ -148,13 +150,14 @@ function convert( $src, $dest, $options ) {
     }
 
     $mbits = 1000 * 1000;
-    if ( $bitrate < 1 * $mbits || $height < 480 ) {
+    $base = intval( $mbits * $options['quality'] );
+    if ( $bitrate < 1 * $base || $height < 480 ) {
         $frameWidth = 640;
         $frameHeight = 360;
-    } elseif ( $bitrate < 2 * $mbits || $height < 720) {
+    } elseif ( $bitrate < 2 * $base || $height < 720) {
         $frameWidth = 854;
         $frameHeight = 480;
-    } elseif ( $bitrate < 4 * $mbits || $height < 1080) {
+    } elseif ( $bitrate < 4 * $base || $height < 1080) {
         $frameWidth = 1280;
         $frameHeight = 720;
     } else {