diff --git a/resources/layouts/_default/page.iframe.twig b/resources/layouts/_default/page.iframe.twig
index 970f518ea..db2aac236 100644
--- a/resources/layouts/_default/page.iframe.twig
+++ b/resources/layouts/_default/page.iframe.twig
@@ -22,8 +22,8 @@
     {%- if page.videos is defined ~%}
     <video id="player" playsinline controls preload="auto"{% if page.poster|default(page.image|default) %} poster="{{ asset(page.poster|default(page.image|default)) }}"{% endif %}>
       {%- for video in page.videos ~%}
-      {%- set asset = asset(video) ~%}
-      <source src="{{ url(asset) }}" type="{{ asset.subtype }}"/>
+        {%- set asset_video = asset(video) ~%}
+      <source src="{{ url(asset_video) }}" type="{{ asset_video.subtype }}"/>
       {%- endfor ~%}
     </video>
     {%- else ~%}
diff --git a/resources/layouts/_default/page.oembed.twig b/resources/layouts/_default/page.oembed.twig
index 17d35e8b2..5205c5efb 100644
--- a/resources/layouts/_default/page.oembed.twig
+++ b/resources/layouts/_default/page.oembed.twig
@@ -30,7 +30,9 @@
   {%- endif ~%}
   "provider_name": "{{ site.title }}",
   "provider_url": "{{ url('/', {canonical: true}) }}",
+  {%- if author.name is defined ~%}
   "author_name": "{{ author.name }}",
+  {%- endif ~%}
   {%- if author.url is defined ~%}
   "author_url": "{{ author.url }}",
   {%- endif ~%}
@@ -38,6 +40,8 @@
   {%- if 'iframe' in page.output ~%}
   "embed_url": "{{ url(page, {canonical: true, format: 'iframe'}) }}",
   {%- endif ~%}
+  {%- if opengraph.description is defined ~%}
   "description": "{{ opengraph.description }}"
+  {%- endif ~%}
 }
 {% endblock %}
\ No newline at end of file
diff --git a/resources/layouts/partials/jsonld.js.twig b/resources/layouts/partials/jsonld.js.twig
index 3f0209b6d..cd5242e65 100644
--- a/resources/layouts/partials/jsonld.js.twig
+++ b/resources/layouts/partials/jsonld.js.twig
@@ -118,14 +118,16 @@
           "@context": "https://schema.org",
           "@type": "VideoObject",
           "name": "{{ title|default(page.title)|e }}",
+          {%- if page.description is defined ~%}
           "description": "{{ page.description|e }}",
-          {%- if page.poster is defined ~%}
+          {%- endif ~%}
           "thumbnailUrl": [
             "{{ url(asset(page.poster), {canonical: true}) }}"
           ],
-          {%- endif ~%}
           "uploadDate": "{{ page.date|date('Y-m-dTH:i:sP') }}",
-          "duration": "PT1M54S",
+          {%- if page.duration is defined ~%}
+          "duration": "{{ page.duration|duration_to_iso8601 }}",
+          {%- endif ~%}
           "contentUrl": "{{ url(opengraph.video, {canonical: true}) }}",
           "embedUrl": "{{ url(page, {canonical: true, format: 'iframe'}) }}"
         }
diff --git a/src/Renderer/Extension/Core.php b/src/Renderer/Extension/Core.php
index 50a7c108b..2e0907221 100644
--- a/src/Renderer/Extension/Core.php
+++ b/src/Renderer/Extension/Core.php
@@ -146,6 +146,8 @@ public function getFilters(): array
             new \Twig\TwigFilter('preg_match_all', [$this, 'pregMatchAll']),
             new \Twig\TwigFilter('hex_to_rgb', [$this, 'hexToRgb']),
             new \Twig\TwigFilter('splitline', [$this, 'splitLine']),
+            // date
+            new \Twig\TwigFilter('duration_to_iso8601', ['\Cecil\Util\Date', 'durationToIso8601']),
         ];
     }
 
diff --git a/src/Util/Date.php b/src/Util/Date.php
index 5baf6843e..ffcd423ad 100644
--- a/src/Util/Date.php
+++ b/src/Util/Date.php
@@ -50,4 +50,18 @@ public static function toDatetime($date): \DateTime
 
         return new \DateTime($date);
     }
+
+    /**
+     * Duration in seconds to ISO 8601.
+     * e.g.: '00:00:46.70' -> 'T0M46S'
+     */
+    public static function durationToIso8601(string $duration): string
+    {
+        $time = new \DateTime($duration);
+        $midnight = new \DateTime();
+        $midnight->setTime(0, 0);
+        $period = $midnight->diff($time);
+
+        return $period->format('T%iM%SS');
+    }
 }
diff --git a/tests/fixtures/website/layouts/video.html.twig b/tests/fixtures/website/layouts/video.html.twig
new file mode 100644
index 000000000..608d26362
--- /dev/null
+++ b/tests/fixtures/website/layouts/video.html.twig
@@ -0,0 +1,10 @@
+{% extends '_default/page.html.twig' %}
+
+{% block content %}
+  <video controls width="100%">
+  {%- for video in page.videos ~%}
+    {%- set asset_video = asset(video) ~%}
+    <source src="{{ url(asset_video) }}" type="{{ asset_video.subtype }}" />
+  {%- endfor ~%}
+  </video>
+{% endblock %}
\ No newline at end of file
diff --git a/tests/fixtures/website/pages/Assets/video.md b/tests/fixtures/website/pages/Assets/video.md
new file mode 100644
index 000000000..e9268ea28
--- /dev/null
+++ b/tests/fixtures/website/pages/Assets/video.md
@@ -0,0 +1,12 @@
+---
+title: Video
+image: video/poster.png
+
+duration: 00:00:13
+videos:
+  - video/test.mp4
+poster: video/poster.png
+
+output: [html, iframe, oembed]
+layout: video
+---
diff --git a/tests/fixtures/website/static/video/poster.png b/tests/fixtures/website/static/video/poster.png
new file mode 100644
index 000000000..f1765bad0
Binary files /dev/null and b/tests/fixtures/website/static/video/poster.png differ