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Subject: Extending the metronome plugin

Extending the metronome plugin

From: Thomas Orgis <>
Date: Thu, 19 Jun 2014 08:19:15 +0200


I would like to start a new attempt at improving the metronome plugin
in Rockbox. There are two main points:

1. Support config files with programmed songs (sequences of patterns
with different meters / tempi). I guess it would make sense to use the
"tempo map" format of for this.

2. Have an optical mode, flashing the display (or parts of it) instead
of or in addition to playing a sound.

An Editor for these tempo maps inside the plugin would be bonus, but
for starters I would consider the maps coming from elsewhere. My
platform is a Sansa Clip+. My questions for the seasoned Rockbox devs
are these:

1. Is there an API call to get a file selection dialog or should the
plugin instead register as handler/codec for tempo map files to be started
from the main "files" menu? Excuse me for not finding that answer
myself, I didn't find an obvious place where API/plugin design is
documented. Pointers welcome, of course.

2. Is using the display as flashing indicator LED feasible? I guess it
should be for the Clip+, as it's just a little grid of OLEDs. But the
question would be if it can be done quickly in a timely manner to serve
as metronome (thinking of switching the whole upper or lower half for
opposing tick/tock). Since there is no background illumination, it
should be rather power conservative to have all black pixels most of
the time, right? And regarding the speed/latency: I remember running
Doom on that display, so that should technically work;-)

I'm a seasoned C developer (some might recognize me for maintaining
mpg123 over the last 8 years) and am confident to get the job done for
giving Rockbox an awesome metronome, once I got the starting points. I
did read the source of the existing metronome plugin and would start
from there.

Alrighty then,


Received on 2014-06-19

Page was last modified "Jan 10 2012" The Rockbox Crew