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Topic: Pathological example of a intersample peak, 11dB (Read 3397 times) previous topic - next topic

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  • Rescator
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Pathological example of a intersample peak, 11dB
Pathological example of a intersample peak that was artificially created:

~0dB peak, ~20dBFS RMS (squarewave), +10.87dB intersample peak, 44.1KHz, 32bit float.


Discussion thread for this sample: http://www.hydrogenaudio.org/forums/index....showtopic=98753

The red line is 0dBFS, the white line is -1dBFS, even without oversampling one can see the intersample peak is at ~+8.5dBFS, and settles on +10.87dBFS after 2x (or more) oversampling.
  • Last Edit: 09 January, 2013, 10:45:54 PM by Rescator

  • bandpass
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Pathological example of a intersample peak, 11dB
Reply #1
Probably not a big problem for the test you are doing, but your input sample is a bit weird -- not even vaguely symmetrical.  Here's a way to generate a clean input sample:

sox -r 44100 -n InterSamplePeak2.wav synth 220501s 0 25 sin 22050 repeat 1 fade h 5 10 5

  • Rescator
  • [*][*]
Pathological example of a intersample peak, 11dB
Reply #2
Here is a CSV with the result from a scan I did.
The MD5 and CSV was created by a quick tool I made myself, the actual stats was gathered with Sox using the following params. (thanks again bandpass for your sox knowhow).

sox.exe file.wav -n stats upsample 4 sinc -a 40 -t 8k -24k stats

The two stats (peak and rms of the first stats, and the peak from second stats with a +12.04 adjustment to counter the attenuation during the upsampling in sox)

Here follows just one example of the numbers you can do on the attached csv data. Have fun. (PS! the MD5 id is local to the scan/csv file only)
CSV format is: id,peak,rms,isp
peak and rms and isp are all relative to 0 dBFS (0dBFS = +1.0 or -1.0 floating point).


5824 tracks.
Peak -1.18 dBFS (Min -28.03, Max 0.00)
ISP -0.45 dBFS (Min -28.02, Max 9.54)
ISP/Peak Delta -1.63 dB (Min -56.05, Max 9.54)
RMS -16.89 dBFS (Min -46.18, Max -6.34)

27.59% ISP <-1 dBFS
72.41% ISP >-1 dBFS

44.33% ISP -1 to 0 dBFS
19.95% ISP 0 to 1 dBFS
3.71% ISP 1 to 2 dBFS
0.79% ISP 2 to 3 dBFS
0.21% ISP 3 to 4 dBFS
0.34% ISP 4 to 5 dBFS
0.31% ISP 5 to 6 dBFS
1.56% ISP 6 to 7 dBFS
1.18% ISP 7 to 8 dBFS
0.00% ISP 8 to 9 dBFS
0.02% ISP 9> dBFS