[vox-tech] Marking Audio file based on Freq.

Bill Broadley bill at cse.ucdavis.edu
Thu Mar 13 22:10:24 PDT 2008


> Unfortunately I don't have any uncompressed samples of that species yet 
> or even know the real origin of that file. The devices I built are going 
> to deliver me flac files specifically because of that issue. (Cowon A3)

Nice.  Stereo or mono.

> After looking at the text dump some more and a spectrogram I actually 
> found the base frequency of the call is more in the 150-250 hz range, 
> but I need to play with it this weekend and run some real descriptive 
> stats and try those calculations.

Cool.  Certainly filtering out the unused frequencies will help on multiple
fronts (mostly CPU time and storage)

> The key to the playback part, is that I'm not the one who will be 
> listening to them. So it's important that I flag the spots of interest 
> and then pass the info on to less technical people who will listen to 
> each spot, and look at the graphs. So giving them and interface that I 
> don't have to write is relatively important.

I'm missing the don't have to write part.    Easy to use I get.

> You'll notice both Audacity 
> and Sonic have nice pretty color spectrogram options.

Right as does the cut and paste source code I pointed to.

I just figured it's easier to do something like:

for i in 0 to end_of_audio()
{
	if time[i][500]>40 # if 500 hz > -40gb
		queue_time(i)
}
for i in times:
	display_time(i)
	if (query_yes_or_no())
		record(yes,i)
	else
		record(no,i)

Seems like it would be as easy or easier than using an audio editing,
especially since it would handle the user answers instead of saying,
look at every sample I marked on track #3 and then record in a spreadsheet
which ones are real with a timestamp or sample number.


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