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content from a web server. Having a direct HTTP link to the content also comes in handy when you want to
transfer a few media files to your laptop to view on the road.
Video from the Internet
Coherence has support for obtaining video data from the BBC, Movie trailers from Apple, video from Ted
Talks, and images from various photo sharing sites. At the time I tested the system, Apple did not work
through Coherence. The Ted Talks worked perfectly. Content from the BBC is mostly through MP3 audio
files, and some of those files are not available to users "outside of the UK." Adding these video and audio
sources to your Coherence server is as simple as adding the plugin to your configuration and telling
Coherence how often (in hours) to obtain updates from those services (Listing 2).
Listing 2: Adding Audio and Video Sources
01 [plugins]
02 ...
03 [[BBCStore]]
04 name = BBC
05 refresh = 1
06
07 [[AppleTrailersStore]]
08 name = Apple Trailers
09 refresh = 4
10
11 [[TEDStore]]
12 name = TEDtalks
13 refresh = 2
UPnP Ready Clients
Both Totem and Rhythmbox can consume content from UPnP servers. Install the totem-upnp and
rhythmbox-upnp packages, respectively. Totem (Figure 5) presents the content in a deeper tree view than
Rhythmbox (Figure 6), which might help you find the broadcast you are after, but Totem can't seek in large
video files. (I tested Totem version 2.26.3 using GStreamer 0.10.24 - later versions might improve this
situation.) As Rhythmbox is primarily an audio player, it doesn't show or play most video files from a UPnP
server. VLC allows seeking in video media from UPnP servers, but you have to wait for the content up to the
point you have seeked to be copied over the network. And even when running on gigabit networks, seeking in
a 10GB file by copying the intermediate content can make for an interesting test of patience. The Media
Streamer client for Maemo works reasonably well but has rather limited codec support. I had trouble playing
the BBC through Media Streamer, but Ted Talks came through just fine.
In the Stream 4
Figure 5: Listening to the BBC through Totem.
Figure 6: Listening to the BBC through Rhythmbox.
Final Words
Some common video and audio players already support UPnP. Remember, too, that UPnP AV has explicit
support for the separation of the controller from the content playback, so you should be able to run a controller
on a touch screen device like a maemo tablet to tell a video player such as VLC to start, stop, or skip the
current file.
INFO
[1] Universal Plug and Play: http://en.wikipedia.org/wiki/Universal_Plug_and_Play
[2] Coherence: http://coherence.beebits.net/
THE AUTHOR
Ben Martin has worked on filesystems for more than 10 years. He offers consulting services focused on
libferris, filesystems, and search solutions.
In the Stream 5
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