[DLNA] Debugging a UPnP / DLNA Media Server

Post by **rednoah** » 14 Jun 2024, 05:46

First and foremost, please use the dlna.groovy script to discover all the media servers on the local network and to print the content directory tree for inspection and debugging purposes:

Shell: Select all

filebot -script fn:dlna --output ./Result

Here's how a DLNA client connects to a DLNA media server:

Use SSDP (Simple Service Discovery Protocol) to send a M-SEARCH * HTTP/1.1 request to every device on the local network:
http: Select all
```
M-SEARCH * HTTP/1.1
HOST: 239.255.255.250:1900
MAN: "ssdp:discover"
MX: 5
ST: urn:schemas-upnp-org:device:MediaServer:1
```

Each media server on the network will then respond with the LOCATION of its device descriptor:

http: Select all

HTTP/1.1 200 OK
...
LOCATION: http://192.168.0.10:50001/desc/device.xml
...
ST: urn:schemas-upnp-org:device:MediaServer:1

The device descriptor will then tell us the controlURL of the ContentDirectory service:

xml: Select all

<root xmlns="urn:schemas-upnp-org:device-1-0">
	...
	<device>
		<deviceType>urn:schemas-upnp-org:device:MediaServer:1</deviceType>
		<modelDescription>Synology DLNA/UPnP Media Server</modelDescription>
		...
		<serviceList>
			...
			<service>
				<serviceType>urn:schemas-upnp-org:service:ContentDirectory:1</serviceType>
				...
				<controlURL>/ContentDirectory/control</controlURL>
				...
			</service>
		</serviceList>
	</device>
</root>

We can then send a SOAP request for ObjectID=0 (i.e. root directory) to the controlURL via a HTTP POST request:

Shell: Select all

curl "http://192.168.0.10:50001/ContentDirectory/control" -A "DLNADOC/1.50" \
-H 'SOAPACTION: "urn:schemas-upnp-org:service:ContentDirectory:1#Browse"' \
-H 'Content-Type: text/xml; charset="utf-8"' -d '<?xml version="1.0"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:Browse xmlns:u="urn:schemas-upnp-org:service:ContentDirectory:1"><ObjectID>0</ObjectID><BrowseFlag>BrowseDirectChildren</BrowseFlag><StartingIndex>0</StartingIndex><RequestedCount>100</RequestedCount><SortCriteria></SortCriteria></u:Browse></s:Body></s:Envelope>'

http: Select all

POST /ContentDirectory/control HTTP/1.1
HOST: 192.168.0.10:50001
...
SOAPACTION: "urn:schemas-upnp-org:service:ContentDirectory:1#Browse"
USER-AGENT: DLNADOC/1.50

xml: Select all

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
	<s:Body>
		<u:Browse xmlns:u="urn:schemas-upnp-org:service:ContentDirectory:1">
			<ObjectID>0</ObjectID>
			<BrowseFlag>BrowseDirectChildren</BrowseFlag>
			<Filter>*</Filter>
			<StartingIndex>0</StartingIndex>
			<RequestedCount>5000</RequestedCount>
			<SortCriteria></SortCriteria>
		</u:Browse>
	</s:Body>
</s:Envelope>

The SOAP response will give us the Result as XML text element:

xml: Select all

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
	<s:Body>
		<u:BrowseResponse xmlns:u="urn:schemas-upnp-org:service:ContentDirectory:1">
			<Result>&lt;DIDL-Lite ... &lt;/DIDL-Lite&gt;</Result>
			<NumberReturned>3</NumberReturned>
			<TotalMatches>3</TotalMatches>
			<UpdateID>10</UpdateID>
		</u:BrowseResponse>
	</s:Body>
</s:Envelope>

After decoding and parsing the Result element as XML we can now see the root directory listing:

xml: Select all

<DIDL-Lite xmlns="urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:upnp="urn:schemas-upnp-org:metadata-1-0/upnp/" xmlns:sec="http://www.sec.co.kr/" xmlns:dlna="urn:schemas-dlna-org:metadata-1-0/">
	...
	<container id="33" parentID="0" restricted="1">
		<dc:title>Video</dc:title>
		<upnp:class>object.container.storageFolder</upnp:class>
	</container>
</DIDL-Lite>

Each directory listing will tell us the container id for each subfolder, so we can then recursively request and traverse the entire folder structure on the media server.

Let's have a look at a specific directory listing for a video folder that a DLNA client might be working with:

Console Output: Select all

$ filebot -script fn:dlna --output ./Result --q "33" --db "http://192.168.0.10:50001/desc/device.xml"
[ObjectID=33$@3286] The Man from Earth (2007)
└─ albumArtURI [profileID=JPEG_TN] http://192.168.0.10:50002/transcoder/jpegtnscaler.cgi/vfolderart/3286.jpg
└─ res [duration=1:27:11.000, nrAudioChannels=6, protocolInfo=http-get:*:video/x-matroska:DLNA.ORG_OP=01;DLNA.ORG_FLAGS=01700000000000000000000000000000, sampleFrequency=48000, size=9756560873, bitrate=1864868, resolution=1920x1080] http://192.168.0.10:50002/v/NDLNA/3286.mkv
└─ res [protocolInfo=http-get:*:image/jpeg:DLNA.ORG_PN=JPEG_TN;DLNA.ORG_FLAGS=00f00000000000000000000000000000] http://192.168.0.10:50002/transcoder/jpegtnscaler.cgi/vfolderart/3286.jpg

xml: Select all

<DIDL-Lite xmlns="urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:upnp="urn:schemas-upnp-org:metadata-1-0/upnp/" xmlns:sec="http://www.sec.co.kr/" xmlns:dlna="urn:schemas-dlna-org:metadata-1-0/">
	<item id="33$@3286" parentID="33" restricted="1">
		<dc:title>The Man from Earth (2007)</dc:title>
		<upnp:class>object.item.videoItem</upnp:class>
		<dc:date>2024-06-14T00:00:00</dc:date>
		<upnp:albumArtURI dlna:profileID="JPEG_TN">http://192.168.0.10:50002/transcoder/jpegtnscaler.cgi/vfolderart/3286.jpg</upnp:albumArtURI>
		<res protocolInfo="http-get:*:video/x-matroska:DLNA.ORG_OP=01;DLNA.ORG_FLAGS=01700000000000000000000000000000" resolution="1920x1080" size="9756560873" bitrate="1864868" duration="1:27:11.000" nrAudioChannels="6" sampleFrequency="48000">http://192.168.0.10:50002/v/NDLNA/3286.mkv</res>
		<res protocolInfo="http-get:*:image/jpeg:DLNA.ORG_PN=JPEG_TN;DLNA.ORG_FLAGS=00f00000000000000000000000000000">http://192.168.0.10:50002/transcoder/jpegtnscaler.cgi/vfolderart/3286.jpg</res>
	</item>
</DIDL-Lite>