Document the new DLNA DMS integration (#21624)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

source/_integrations/dlna_dms.markdown

@@ -0,0 +1,60 @@
+---
+title: DLNA Digital Media Server
+description: Instructions on how to access media stored on a DLNA DMS device with Home Assistant.
+ha_category:
+  - Media Source
+ha_release: 2022.3
+ha_iot_class: Local Polling
+ha_config_flow: true
+ha_codeowners:
+  - '@chishm'
+ha_domain: dlna_dms
+ha_platforms:
+  - media_source
+ha_ssdp: true
+---
+
+The DLNA Digital Media Server integration allows you to browse and play media from a [DLNA Digital Media Server](https://www.dlna.org/). Configured DMS devices act as a [Media Source](/integrations/media_source/) and can be browsed in the Media panel.
+
+{% include integrations/config_flow.md %}
+
+## Renaming
+
+The name/title of the DMS device is the same as the title of the config entry. It can be changed on the Integrations Configuration page from the three-dot menu.
+
+## Media source URIs
+
+Media source URIs for DLNA DMS look like `media-source://dlna_dms/<source_id>/<media_identifier>`.
+
+Here `<source_id>` is the slugified name of the DMS device. For example, "DLNA Server" becomes "dlna_server". If multiple DMS devices have the same name, an underscore and a unique number will be appended to the end of some of them, e.g., "server", "server_1", "server_2".
+
+The `<media_identifier>` can have one of three forms:
+
+- `path/to/file` or `/path/to/file`: Slash-separated path through the Content Directory. This must refer to a unique media item.
+- `:ObjectID`: Colon followed by a server-assigned ID for an object.
+- `?query`: Question mark followed by a query string to search for, see [DLNA ContentDirectory SearchCriteria](http://www.upnp.org/specs/av/UPnP-av-ContentDirectory-v1-Service.pdf) for the syntax. The first result found will be used.
+
+URIs generated while browsing will look like the Object ID form above. However, all three forms will work with the [media_player.play_media service](integrations/media_player/#service-media_playerplay_media).
+
+### Examples
+
+Using a path URI:
+
+```yaml
+service: media_player.play_media
+target:
+  entity_id: media_player.living_room_tv
+data:
+  media_content_id: "media-source://dlna_dms/my_server/videos/favourites/Epic Sax Guy 10 Hours.mp4"
+```
+
+Using a query URI:
+
+```yaml
+service: media_player.play_media
+target:
+  entity_id: media_player.living_room_tv
+data:
+  media_content_id: 'media-source://dlna_dms/my_server/?dc:title="Big Buck Bunny"'
+```
+