Re: [LAU] USB device gives wrong data?

Fons,

   Thanks for the response.

   What you suggested is what I did but I only use one 'silence byte'. That
is definable to match the 'silence byte' for different devices. It seems
to work OK.

   Do you think that a range of 'silence bytes' would work better?

William Estrada
MrUmunhum@email-addr-hidden
Mt-Umunhum-Wireless.net ( http://Mt-Umunhum-Wireless.net )
Ymessenger: MrUmunhum

Fons Adriaensen wrote:
> On Mon, Oct 22, 2007 at 10:17:50AM -0700, william estrada wrote:
>
>> Yes, the format is U8, it is a simple recording program to make '.wav'
>> files. The filtering does work when adjusting the 'silence byte'. It
>> appears that the device drivers are not consistent with this value?
>> So I will be adding an option to change the value of the 'silence byte'.
>>
>> How do I use the RMS value to remove noise? A URL that I could read?
>
> It's probably not worth the effort for 8 bits. What you see is a simple
> DC offset. Probably the easy approach is to consider a range of values
> e.g. 0x7E...0x82 as silence. Any value outside the range starts the
> recording, until you find a long series of samples within the silence
> range.
>
> So the algo would be:
>
> If you find a value in the silence range, increment a counter.
> If the counter reaches a certain value, stop.
> If you find a value outside the range, start and reset the
> counter.
>
> You could also use a counter to avoid too many false starts.
>
> Ciao
>
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Received on Wed Oct 24 00:15:04 2007