Re: [LAD] meterbridge 0.9.2 IEC-scale bug & fix

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To: <linux-audio-dev@...>
Date: Wednesday, September 26, 2012 - 3:39 pm

On Wed, Sep 26, 2012 at 12:08:00PM +0100, Chris Cannam wrote:

> On 11 June 2012 18:47, Robin Gareus wrote:

There is more to fix.

The meterbridge website still claims that those meters 'almost' conform
to some standards while in fact they even don't come close.

According to the standard, a VU measures the average of the absolute
value. For a steady input signal around 1 kHz, it must rise to 99% of
the real value in 300ms and overshoot it by 1 to 1.5% before falling
back to 100%. The one from meterbridge measures RMS and rises to the
final value in around 5.3ms, that is more than 50 times too fast (at
a sample rate of 48 kHz, and worse for higher sample rates).

According to the standards, a PPM or IEC meter must have a controlled
rise time of 5 or 10ms (depending on the standard). The one from
meterbridge indicates peak sample values instead.

Ciao,

--
FA

A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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Messages in current thread:
[LAD] meterbridge 0.9.2 IEC-scale bug &amp; fix, Robin Gareus, (Mon Jun 11, 5:47 pm)
Re: [LAD] meterbridge 0.9.2 IEC-scale bug &amp; fix, Chris Cannam, (Wed Sep 26, 11:08 am)
Re: [LAD] meterbridge 0.9.2 IEC-scale bug & fix, Fons Adriaensen, (Wed Sep 26, 3:39 pm)
Re: [LAD] meterbridge 0.9.2 IEC-scale bug &amp; fix, Chris Cannam, (Wed Sep 26, 8:13 pm)
Re: [LAD] meterbridge 0.9.2 IEC-scale bug &amp; fix, Gene Heskett, (Wed Sep 26, 5:24 pm)
Re: [LAD] meterbridge 0.9.2 IEC-scale bug &amp; fix, Fons Adriaensen, (Wed Sep 26, 7:28 pm)
Re: [LAD] meterbridge 0.9.2 IEC-scale bug &amp; fix, Gene Heskett, (Thu Sep 27, 3:57 am)