Update README.md

README.md

@@ -21,6 +21,36 @@ Translations (sorted by ISO name):
 
 This app does not require any server-side plugins.
 
+## Video Previews/Thumbnails
+The previews shown in the app are generated by the Nextcloud server. By default, Nextcloud server does not generate previews for video files. To enable this feature:
+1. Install `avconv` or `ffmpeg` on the server
+2. Modify `config.php` according to https://docs.nextcloud.com/server/latest/admin_manual/configuration_server/config_sample_php_parameters.html#previews
+    - The most important change is adding `OC\\Preview\\Movie` to `enabledPreviewProviders`
+    - If `enabledPreviewProviders` is missing in your `config.php`, the following snippet will preserve the default settings
+```
+<?php
+$CONFIG = array (
+  ...
+  'enabledPreviewProviders' =>
+  array (
+    0 => 'OC\\Preview\\BMP',
+    1 => 'OC\\Preview\\GIF',
+    2 => 'OC\\Preview\\JPEG',
+    3 => 'OC\\Preview\\MarkDown',
+    4 => 'OC\\Preview\\MP3',
+    5 => 'OC\\Preview\\PNG',
+    6 => 'OC\\Preview\\TXT',
+    7 => 'OC\\Preview\\XBitmap',
+    8 => 'OC\\Preview\\OpenDocument',
+    9 => 'OC\\Preview\\Krita',
+    10 => 'OC\\Preview\\Movie',
+  ),
+);
+```
+
+## HEIC Previews/Thumbnails
+Add `OC\\Preview\\HEIC` to `enabledPreviewProviders` in `config.php`. See [Video Previews/Thumbnails](#video-previewsthumbnails) for more details.
+
 ## Web Support
 Web support is **EXPERIMENTAL** and is provided on a best effort basis. It may be subject to change at any time without notice. Please read carefully the instructions listed below or else the app will likely fail to work.