Re: [SoX-users] Generating multiple spectrograms

[Ulrich K. <ul...@ch...>]

Happy New Year to everyone! (I know, it's still 2012 in the Americas;  
just re-read it later if you live there. ;-) )

Peter Shute <ps...@nu...>:

> but it might be more generally useful if it supported numbered  
> spectrogram output files for use with trim and : newfile : restart  
> like it does with audio files, or even if it simply created them if  
> necessary.
> Are such future enhancements possible with SoX?

Possible, yes. This is a very specific task, however, and I doubt that  
the added complexity is worth it.

But, a new approach to your problem recently crossed my mind:
Make a text file like the attached spsp.txt. You might need to add  
more lines at the end if (some of) your audio files are longer than  
30*3 = 90 minutes. Then, run SoX like this:
   sox --effects-file spsp.txt test.wav -n
This is quite similar to the newfile-restart concept, just a little  
less elegant, since the spectrogram file names aren't chosen  
automatically. A particular advantage is that you can reuse the same  
spsp.txt and the same command line for different audio files. If the  
audio is only, say, 15 minutes long, the lines that aren't needed will  
be ignored.

By the way, if you don't already know about it, you might be  
interested in the -r option to the spectrogram effect ("raw"  
spectrogram, no legend). This would need to be added to each line in  
spsp.txt via search-and-replace.

[Imagemagick]
> That was my intention, although Ulrich has found it can't handle  
> 100,000 pixels.

I can't promise that. :-)  It didn't work for me, but it might have  
been an uncaught out-of-memory situation (thus work OK on a system  
with more memory), or a problem in the X display driver (thus work on  
Windows, or work when the result is written to a file and not  
displayed).

Ulrich