diff --git a/src/Map.php b/src/Map.php
index 787a2f6..b427110 100644
--- a/src/Map.php
+++ b/src/Map.php
@@ -6,6 +6,9 @@ class Map
 {
     protected MappableMedia $media;
     protected string $path;
+    /** @var Stream[] */
+    protected array $streams = [];
+    protected array $metadata = [];
 
     public function __construct(MappableMedia $media)
     {
@@ -25,4 +28,31 @@ class Map
 
         return $this;
     }
+
+    public function addMetadata(array|string $keyOrData, string $value = null): static
+    {
+        if (is_array($keyOrData)) {
+            array_walk($keyOrData, fn($v, $k) => $this->addMetadata($k, $v));
+
+            return $this;
+        }
+
+        $this->metadata[$keyOrData] = $value;
+
+        return $this;
+    }
+
+    public function buildCommand(): array
+    {
+        $commands = [];
+        foreach ($this->streams as $idx => $stream) {
+            array_push($commands, ...$stream->buildCommand($idx));
+        }
+        foreach ($this->metadata as $k => $v) {
+            array_push($commands, '-metadata', "{$k}={$v}");
+        }
+        $commands[] = $this->path;
+
+        return $commands;
+    }
 }
diff --git a/src/MappableMedia.php b/src/MappableMedia.php
index c4881ad..c25530b 100644
--- a/src/MappableMedia.php
+++ b/src/MappableMedia.php
@@ -322,9 +322,11 @@ class MappableMedia extends AbstractMediaType
      */
     protected function buildMaps(array $maps): array
     {
-        $out = [];
-        // @todo
+        $commands = [];
+        foreach($maps as $map) {
+            array_push($commands, ...$map->buildCommand());
+        }
 
-        return $out;
+        return $commands;
     }
 }