James "Doc" Livingston doclivingston at
Thu Mar 27 06:17:34 PDT 2008

On Thu, 2008-03-27 at 12:25 +0100, Stanislav Brabec wrote:
> The specification looks nice, but currently a bit incomplete. Missing
> things:
> - Tracklist handling is a bit vague. Additionally, different
> applications may have different needs: implicit "playlist" 1-last when
> CD is inserted x no default playlist in mpd, Artist/Album/TrackNo-Song x
> Artist/Song.

As well as potential vagueness you mention, a chunk of the MPRIS API is
very 'tracklist-based' player oriented. As I mentioned a while back when
the MPRIS announcement was cross-posted to 10 or so mailing lists, those
parts of the API don't make a whole lot of sense to player which aren't

For example, I work on Rhythmbox which is a 'library-based' player, but
these comments would apply to several other similar players. For such
players, what should the tracklist refer to? The entire library, the
currently selected part of the library (maybe a playlist), a queue of
upcoming tracks (c.f. iTunes' party shuffle, for those player which have
such a thing)?

However, the tracklist parts to seem to be more cleanly separated than
last time I saw it, so just not implementing that part is certainly an
option for such players. Would it be better to not implement the
tracklist in a library-based player, or do the best implementation we
can, which might not have quite the same semantics as proper
tracklist-based players?

If this takes off, we could probably have some discussion about a common
interface to the libraries of players, which

> - Applications may want to broadcast "just started to play new
> song" (for example pidgin does the same when it gets new message and is
> configured so), "new medium was inserted".

That signal is part of the Player object in the MPRIS spec, so I guess
the application could implement that saying it doesn't support
next/previous, and not doing anything if the play/pause method is

That said, how many media players would want to send that signal without
having some basuc playback control?

> - Missing support for advanced mixer settings: Bass, Breble, 3D,
> External Amplifier power on/off.

This sounds much more like the properties of your sounds card's mixer
than part of a media player. I don't know of any media players which
turn your external amplifier on and off.


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