[linux-audio-user] Re: Analyzing ogg files

[Mark Knecht]

On Tue, 2003-12-02 at 13:06, Andrew Burgess wrote:
> >> Is there a DC offset which the cheap card is eating?
> 
> >A DC offset is an interesting idea. How would I test for that?
> 
> sox <file> -e stat
> 
> displays midline amplitude.
> 
> Or try a highpass filter, just as a test.
> 

More data, but I'm not sure there's an answer there yet. The first file
creates a very loud glitch sound, which the second one doesn't. The
midline value seems better on the first, assuming this represents DC
offset.

bash-2.05b$ sox gmc2.ogg -e stat
Samples read:          26972160
Length (seconds):    305.806803
Scaled by:         2147483647.0
Maximum amplitude:     0.999969
Minimum amplitude:    -1.000000
Midline amplitude:    -0.000015
Mean    norm:          0.138033
Mean    amplitude:     0.000003
RMS     amplitude:     0.189967
Maximum delta:         0.959961
Minimum delta:         0.000000
Mean    delta:         0.093997
RMS     delta:         0.128996
Rough   frequency:         4766
Volume adjustment:        1.000

bash-2.05b$ sox examplesustain.ogg -e stat
Samples read:          11361130
Length (seconds):    128.810998
Scaled by:         2147483647.0
Maximum amplitude:     0.649841
Minimum amplitude:    -0.661896
Midline amplitude:    -0.006027
Mean    norm:          0.069344
Mean    amplitude:     0.002177
RMS     amplitude:     0.092420
Maximum delta:         0.784546
Minimum delta:         0.000000
Mean    delta:         0.072115
RMS     delta:         0.095279
Rough   frequency:         7235
Volume adjustment:        1.511
bash-2.05b$