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Subject: berzerk peak meter? Alpha testers wanted.
From: Philipp Pertermann (
Date: 2002-09-22

I still am fiddling with the volume meter. Now I've come to
a point where I have to make a decision concerning the
system load <-> precision.

The problem:
The MAS chip provides a 'quasi peak detector' that we can
read values from. It doesn't work very well. If a peak
happens in the music somewhen between two read outs we miss
it. Thus the more often we read values the higher ist the
probability that we actually hit a peak.
Reading out the MAS often is not a good idea in two
1.) it increases the power consumption
2.) it increases the system load. If the system load becomes
    high stops / skips might occur.

The solutions:
I've implemented two strategies for reading out the MAS

normal mode | berzerk mode
reads once per redraw | 1 - 20 reads per redraw
- lower precision | + higher precision
- clips undetectable | + clips detectable
+ lower power consumption | - higher power consumption
+ lower system load | - higher system load

In both modes the 'frame rate' is the same so you don't see
much difference unless you watch out for peaks.

I put an unofficial version on
In the menu General settings ->Display->Peak meter you can
switch berzerk mode on / off.

Now I want to know what you think: Do we need that berzerk
mode or is the normal mode enough? Do you encounter any
problems playing back mp3 in berzerk mode?


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