• Status Closed
  • Percent Complete
  • Task Type Bugs
  • Category User Interface → Themes
  • Assigned To No-one
  • Operating System All players
  • Severity Low
  • Priority Very Low
  • Reported Version Daily build (which?)
  • Due in Version Undecided
  • Due Date Undecided
  • Votes
  • Private
Attached to Project: Rockbox
Opened by DervishD - 2007-07-15
Last edited by nicolas_p - 2007-07-23

FS#7441 - Volume is not correctly computed when using %?pv instead of %pv

The volume is not “translated” correctly if you use %?pv. The current formula, obtained from the source code, is:

(Number of slots in conditional - 3) * (volume - MAXVOLUME)
----------------------------------------------------------- + 2
                   MAXVOLUME - MINVOLUME

Since any level above 0dB is forced to use the last slot in the conditional, 0dB is forced to use the next-to-last and MINVOLUME is forced to use slot 1, the formula is not right. For example, the iAudioX5 has MAXVOLUME 6, MINVOLUME -73, so the formula will be:

(N-3) * (vol + 73)
—————— +2

Thus, if N=80 (for 1:1 correspondence between different dB values including 0 and slots), the max slot used will be:

77 * (72)
——— + 2 = 72, and it should be 78


If we take into account the “forced” slots, then N=75, and the max slot used will be:

72 * (72)
——— + 2 = 67, and it should be 73


A correct formula can be this:

(N-3) * (vol - MIN - 1)
———————– + 2

  1. 1 - MIN

Any other formula in the form y=mx+b can be used to map the dB values to the slots in the conditional, as long as m is calculated as “Number of slots in the conditional - 3) / (real dB steps to map, ignoring the forced values that won’t be EVER mapped by this function)”. The one presented above is the first I’ve thought of, and of course it can be improved so it is computed faster. I have a quick’n’dirty test that shows the mappings for an iAUDIO, written in shell script (ouch!).

Please contact me if you want a patch instead of this.
Raúl Núñez de Arenas Coronado

Closed by  nicolas_p
2007-07-23 17:11
Reason for closing:  Fixed
Additional comments about closing:   Warning: Undefined array key "typography" in /home/rockbox/flyspray/plugins/dokuwiki/inc/parserutils.php on line 371 Warning: Undefined array key "camelcase" in /home/rockbox/flyspray/plugins/dokuwiki/inc/parserutils.php on line 407

The proposed fix is in SVN. Thanks for the detailed report :)


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