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JohnVo
JohnVo
Inspiring
May 16, 2017
Answered

calculate entire RMS of an audiofile ,are audio statistics accurate?

  • May 16, 2017
  • 1 reply
  • 3320 views

hi

about are the audtio statistics of an entire audio file accurate ?

reading a forum about it , i have read

it's impractical to calculate the true RMS of the entire file, so most algorithms do some time-windowing and take an average-of-RMS values (or maybe an RMS-of-RMS values if that makes sense mathematically). So... two different applications may report two slightly different RMS values.

&

and, the average may  also be an average-of-averages over the length of the file.

is it true?

thanks

This topic has been closed for replies.
Correct answer SteveG_AudioMasters_

Giovannivolontè  wrote

 

is it true?

Yes.

Now what?

1 reply

SteveG_AudioMasters_
Community Expert
SteveG_AudioMasters_Community ExpertCorrect answer
Community Expert
May 16, 2017

Giovannivolontè  wrote

 

is it true?

Yes.

Now what?

JohnVo
JohnVoAuthor
Inspiring
May 17, 2017

it's impractical to calculate the true RMS of the entire file

&

Yes.

Now what?

hi

so audtio statistics is almost unless

i use to find out the peak amplitude & the minimum rsm ampliture

these value are misleading aren't they?

for example i working on this audio , i watch the value with the red arrows

sIJ6xi3.png

thanks

SteveG_AudioMasters_
Community Expert
SteveG_AudioMasters_Community Expert
Community Expert
May 18, 2017

Why are you so surprised? All default settings in Audition are only starting points - you have to adapt them to suit your particular circumstances.

from adobe

Tolerance

Specifies the amplitude variation in clipped regions. A value of 0% detects clipping only in perfectly horizontal lines at maximum amplitude; 1% detects clipping beginning at 1% below maximum amplitude, and so on. (A value of 1% detects most clipping.)

if at tollerance 1% , for audition clipping is -3.97db L -6,12dB i really i don't understand it

2ypjgnS.png

Which declicker?

in the Diagnostics , there is delete silence, declipper,mark audio and declicker

i'm talking about it

There are three, although two of them are very similar.

1)automatic click remover

2) click/pop elimination

3) is the declicker in the Diagnostics ??

thanks SteveG


Giovannivolontè  wrote

if at tollerance 1% , for audition clipping is -3.97db L -6,12dB i really i don't understand it

Technically that's a bug, as in your example, the duration is zero and you can't have a clip lasting zero time! I suspect this has a lot to do with the rapid rate of change at the start of your selection. You will also note that in Amplitude Statistics it says Possibly Clipped Samples - strictly you need to consider the waveform either side of any given sample in order to estimate whether it's part of a clipped sequence. If you make a selection within a file, the rules say that you can only consider the selected part, but that you can't exclude the possibility that in a rapidly changing selection at the start, that the first sample could be a part of a clip in the section immediately prior to your selection - so basically it's playing safe (although I don't think that really, it should do this). But as it's not the easiest thing to detect, there is allowance for errors, and they aren't all obvious. For instance, it's quite possible to create sequences of samples that will overload the output of your sound device without technically clipping at all - by anything up to about 8.5dB. And you need, especially if you're going to normalize a file, to take account of this. Now, these sample sequences are actually legal - even though the clip detector would say they were clipped. So, this is not an exact science, and you have to use a bit of common sense with it.

No, I am not expecting you to take my word for the overload situation. Years ago I created a document (using Audition 1) showing how this can happen, and since this is all based on the Laws of Physics, nothing has changed. You may have a look at the document and its waveforms here: Dropbox - Audition_1.0_overshoot_doc.pdf

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