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Thnaks

Thanks guys its all been very helpful.

Its better now with a running average and also doing a log() of the result.

Still not great as I can not achieve a high sample rate, too much going on in the processor!

Thansk all!

From: "Richard Sloan" Subject: VU meters on LCD Date: Wednesday, January 25, 2006 1:47 PM

I am having difficulty displaying nice VU meter on a character display, right now I have allowed for 8 segments per channel, which I may make into

40 as you get 5 dots across per character.

Now the issue is the bars and very jumpy, either showing a couple or all of them....

I sample the audio every 1/10s and display the bars, I can sample more, but refreshing the display at a high rate is hard due to the fact I need to keep streaming MP3 data and can not miss any.

I also know audio is more logrithmic than what I am doing...

The difference from the softest to loudest on the ADC right now is 80 counts.

I would think I could make a nicer looking VU meter that "follows" the music better.

Any thoughts?

Thanks, Richard.

Reply to
Richard Sloan
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I have lots of experience in products for the television broadcast and post- production industries. The video is usually considered the sexy part but I expect that you now have a better appreciation for the fact that it's the audio that usually present the most challenge.

--
========================================================================
          Michael Kesti            |  "And like, one and one don't make
                                   |   two, one and one make one."
    mrkesti at comcast dot net     |          - The Who, Bargain
Reply to
Michael R. Kesti

(top posting fixed)

Dunno what processor you're using, but unless it's a Pentium you can do a faster approximation of a log using a table look-up or a piecewise-linear approximation. There's been articles about this, and other clever techniques specific to the log function, in Embedded Systems Programming magazine.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Reply to
Tim Wescott

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