wimmel3 said:
> > I'm glad to hear that these kinds of things are being
> planned. But >what exactly is meant by "draw a box around a
> signal"? If you mean drawing on a spectrogram then I'm
> certainly in favour of that.
>
> Not completely sure what Elias meant of course, but I took it
> to mean exactly that. One of the obvious uses would be to
> annotate different species or sound types in a recording.
That would be a very exciting development, and something I've been trying t=
o do for myself anyway.
> > Where do the spectrograms I see on Xeno Canto come from?
> Are they auto generated.
>
> They are generated by the web server during uploading.
Does the person uploading the file have any control over the parameters of =
the spectrogram, i.e. FFT window size, horizontal and vertical scale, bring=
htness and contrast? For some species, the spectrogram shows them up much b=
etter with particular settings, and of course the brightness and contrast o=
ften need tweaking to make them even visible.
And example I've recently come across is Little Button-quail (I think). The=
y're around 400Hz, so hard to see at the bottom of the image if the scale g=
oes up to 15kHz, and the call is long and slow. If the horizontal scale is =
too stretched out they appear on the spectrogram almost as a horizontal lin=
e, but if a more compressed scale is used (about a minute per screen width)=
then they become very obvious little horse-shoe shapes.
> > How would you deal with spectrograms for half hour recordings?
>
> Half an hour is a bit extreme, but the problem is not so much
> in generating them I think, but in the presentation.
> That will have to be tackled before the annotation.
> Here is an example of a long spectrogram:
> http://www.xeno-canto.org/sounds/uploaded/WOEAFQRMUD/ffts/XC62
> 894-full.png
Only 67 seconds and already the image is almost too long and skinny to disp=
lay. Are you considering presenting them in pages? Or displaying a cursor a=
s the recording is played?
> > Are you encouraging the uploading of ambient recordings
> with lots of species in them?
>
> Oh yes. Especially if you know which species can be heard.
> Such recordings bind the collection together nicely. Of
> course to upload them you would need to be able to identify
> at least one species :-) The recording belonging to the long
> sonogram I just mentioned, notes a number of "background
> species": www.xeno-canto.org/62894
It looks like you're only displaying the first 9 seconds of the spectrogram=
. How did you get to the full image?
Peter Shute
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