Subject: Re: [linux-audio-dev] peakfiles and EDL's
From: Jarno Seppanen (jams_AT_cs.tut.fi)
Date: Tue Feb 27 2001 - 12:12:41 EET
Robert Schrem <Robert.Schrem_AT_WiredMinds.de> writes:
> If you take only min/max peak data, the peak data does not neccessarily
> correspond with the 'loudness' of the input singnal. One single
> sample, maybe a glitch, would trigger a whole block of 2048 samples
> at maximum volume. Maybe you want this, maybe not.
>
> And if you would view 30 minutes on a screen you would have to
> resample the peak data again. In the end you might get only
> min/max values that equal to the minimum and maximum range
> of the sample data values. You probably woun't see any meaningfull
> data at all.
Hi! I claim that the peak amplitudes really are about the only relevant
information when displaying PCM audio. They tell whether there is any sound
or not, how loud it (approximately) is and whether the sound is clipping or
not.
Now when you low-pass filter a signal, the peak amplitude values will
_change_, which makes the filtered peak amplitude information unreliable.
Additionally, the high computational cost of resampling vs. max/min peak
picking doesn't justify implementing it for visualisation purposes only.
My 0.02 euros!
-- -Jarno
This archive was generated by hypermail 2b28 : Tue Feb 27 2001 - 12:39:36 EET