Thnaks

Jan 27, 2006 2 Replies
R

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.


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M

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
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T

(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
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