Tuesday, November 28, 2006


The latest announcement of an XMPP based tool to support music fans communities got me thinking how easy this can be implemented by putting together the proper XEPs. Let us consider how to implement an XMPP internet music radio similar to Last.fm. Obviously we would want to put some "social" focus into it. So the scope is simple:

  • Broadcast music to anyone joining the service, even on a temporary basis.
  • Provide a music recommendation system.
  • Provide discussion spaces amongst listeners.

From a protocol standpoint, the basic extensions we would need to provide this type of service are MUC for the community part, and PEP for the announcement part, obviously complemented by the user tune extension.

A very straightforward implementation route would be to create a presence enabled service to which any users could subscribe. The service will expose a number of "stations" implemented as MUC rooms corresponding to musical subjects of interest for the en users. So you may have rooms such as acoustic, alternative, ambiance, classical, dance, dark, experimental, folk, funk, groove, hip-hop, instrumental, jazz, lounge, metal, pop, punk, rap, reggae, rock, ska, techno, world, [add your own genre here]… To add the required "social" trend, one can imagine a system where users are able to tag and rate the music pieces and rooms are automatically created and added from these user preferences.

…kind of a lite social network system, featuring chat and commenting throughout…

The service "identity" is provided through some kind of DJ bot. End users subscribe to the presence of the bot, and are also automatically subscribed to the bot's personal eventing notifications. The bot also request to be subscribed to the user's tune events. Whenever a user come online, then it will receive XEP-0118 notifications from the bot describing what is currently playing in each active room. Obviously each notification will be augmented to include the URI of the corresponding room, to allow creating a "stations" list for the user to choose from.

Tuning to a station boils down to joining the associated MUC room, providing instant conversation between music lovers with similar tastes. These MUC room are augmented to allow direct presence subscription in the case end users prefer to tune directly to specific musical genre. Every "station" has its own DJ bot to which participants in the room can make suggestion as to the next piece of music to be broadcasted. The DJ bot is also in charge of notifying the room participants of the currently playing piece. It does it by simply posting notification to the room and relies on the standard MUC mechanisms to take over the distribution. This has the advantage of having the "station" past program automatically handled through the room history. The notification will be extended with the information about the physical connection URI in order to enable listening to the current track using the user’s workstation features.

Scrobbling tracks is directly available when the user set's its own user tune state. The notification is sent to the service DJ bot for collection and update of the appropriate statistics.

Additional “social” features could be implemented at each “station” level through the appropriate use of mood and activity publications and notifications. If participants are also able to publish their current room information through XEP-0194, the service could be enriched to provide what Wikipedia describes as:

The most-used community feature within Last.fm is the formation of user groups between users with something in common (for example, membership of another internet forum). Last.fm will generate a group profile similar to the users' profiles, showing an amalgamated set of data and charting the group's overall tastes.

I have already mentioned the lack of interest by the web 2.0 crowd in leveraging XMPP killer features. As one can see from the above quick jotting down, many of the puzzle pieces are readily available. In addition, they can be used from standard XMPP clients supporting MUC and PEP, which will be mainstream this year end. Those wanting to add all the bells and whistle of a multimedia UI can do so by building a flash based client with embedded audio and video players, and they will be ready to compete in the Media 2.0 broadcasting space without much technology investment. XMPP has reached a stage where a large number of applications can be built from its existing features set. It is still just a matter of imagination and creativity

Technorati Tags: , , , , , ,

Labels: , ,