Re: [SoX-users] SoX Stats: add peak position? (N Arora)

[nitin a. <nit...@gm...>]

I think with a different speed recordings you could calculate the ratio of
time difference between Max/Min for both recordings and still figure out the
speed change and get yourself "back home" so to speak.

Anyway, I was playing around with that awesome code you wrote up.

I've pasted my results with three files.
But basically:
I got statistics with Sony Sound Forge 9 and SoX 14.3.1's "stat" effect per
your modification.
The Sony appears to be scaling at (-100 to 100) range and the SoX at (-1 to
1) range. Hence, the difference of 2 decimal places between the two outputs.

I might be getting cross-eyed, but this is what I think I'm seeing:

With the "monotest" mono file I used, the location of the Min position was
different between the 2 reports. Max position was identical.
With the stereo tests, the SoX "stat" mod was giving sample values 2x that
of the Sony. That is to say the Sox stat was retrieving 2x the Sony sample
value of the channel with the lowest value for Min.
And it was retrieving 2x the Sony sample value of the channel with the
higher Max value.

I'm getting a little lost on the "stat" output vs Sony since the Sony is per
channel with non mono files.
I guess the same code modification could be done to the "stats" effect to
get the values per channel, a la the Sony.

peace,


Sound Forge 9
monotest.wav
    Cursor position (Samples)            0
    Sample value at cursor (%)           0.000
    Minimum sample position (Samples)    95,230
    Minimum sample value (%)             -25.115
    Maximum sample position (Samples)    125,499
    Maximum sample value (%)             25.117
    RMS level (%)                        10.203
    Average value (%)                    0.000
    Zero crossings (Hz)                  866.06


SoX
monotest.wav
    Samples read:            145530
    Length (seconds):      3.300000
    Scaled by:         2147483647.0
    Maximum amplitude:     0.251174 (sample 125499)
    Minimum amplitude:    -0.251149 (sample 108460)
    Midline amplitude:     0.000012
    Mean    norm:          0.067352
    Mean    amplitude:     0.000003
    RMS     amplitude:     0.102034
    Maximum delta:         0.040679
    Minimum delta:         0.000000
    Mean    delta:         0.010884
    RMS     delta:         0.015914
    Rough   frequency:         1094
    Volume adjustment:        3.98

*the max position matches
* min position doesn't match
-----------------------------------------------------------

Sound Forge 9
stereotest.wav
                                        Left Channel            Right
Channel
    Cursor position (Samples)            0
0
    Sample value at cursor (%)           -0.389
0.000
    Minimum sample position (Samples)    308,076
95,230
    Minimum sample value (%)             -53.473
-25.115
    Maximum sample position (Samples)    2,031,260
125,499
    Maximum sample value (%)             51.904
25.117
    RMS level (%)                        7.375
2.527
    Average value (%)                    0.018
0.000
    Zero crossings (Hz)                  1,329.93
53.11



SoX
stereotest.wav
    Samples read:           4745664
    Length (seconds):     53.805714
    Scaled by:         2147483647.0
    Maximum amplitude:     0.519044 (sample 4062520)
    Minimum amplitude:    -0.534734 (sample 616152)
    Midline amplitude:    -0.007845
    Mean    norm:          0.023978
    Mean    amplitude:     0.000088
    RMS     amplitude:     0.055126
    Maximum delta:         0.534734
    Minimum delta:         0.000000
    Mean    delta:         0.046961
    RMS     delta:         0.077968
    Rough   frequency:         9926
    Volume adjustment:        1.870

* SoX min pos = Sony sample value of 308.076 * 2
* SoX max pos = Sony sample value of 2031260 * 2

-----------------------------------------------------------

Sound Forge 9
stereoswaptest.wav (this is the same as the stereotest.wav file but with the
channels swapped)

                                        Left Channel            Right
Channel
    Cursor position (Samples)            666,112
666,112
    Sample value at cursor (dB)          -Inf.
-23.970
    Minimum sample position (Samples)    95,230
308,076
    Minimum sample value (dB)            -12.001
-5.437
    Maximum sample position (Samples)    125,499
2,031,260
    Maximum sample value (dB)            -12.000
-5.696
    RMS level (dB)                       -31.948
-22.645
    Average value (dB)                   -138.474
-75.074
    Zero crossings (Hz)                  53.11
1,329.93

SoX
stereoswaptest.wav
    Samples read:           4745664
    Length (seconds):     53.805714
    Scaled by:         2147483647.0
    Maximum amplitude:     0.519044 (sample 4062521)
    Minimum amplitude:    -0.534734 (sample 616153)
    Midline amplitude:    -0.007845
    Mean    norm:          0.023978
    Mean    amplitude:     0.000088
    RMS     amplitude:     0.055126
    Maximum delta:         0.534734
    Minimum delta:         0.000000
    Mean    delta:         0.046960
    RMS     delta:         0.077965
    Rough   frequency:         9926
    Volume adjustment:        1.870

SoX min pos = Sony sample value of 308.076 * 2 + 1
SoX max pos = Sony sample value of 2031260 * 2
-----------------------------------------------------------
Nitin Arora
nitaro74 (at) gmail (dot) com
"Hope always, expect never."

humaneguitarist.org
blog.humaneguitarist.org