Spectrum Behaviour

[Cefn Hoile]

>
> The fft is running in floating point precision and is not using any
> hardware acceleration (like SS2). Allowing it to optionally use integer
> fft routines (which we do have) could be worth trying. Alternatively
> trying to apply ORC optimizations to the butterfly operation of the FFT
> library would speed it up.
>
> Both are not trivial things to do ...
>
> Stefan
>
>
Thanks for the suggestions, Stefan.

For interest, here's the result. I was just about able to run the Gstreamer
spectrum element on this eleven year-old Compaq Presario 700 as part of a
shrimping project, now immortalised in video.
https://vimeo.com/44535515

Unfortunately when I try to launch anything substantial on the machine,
like open a browser, the CPU time this takes away from gstreamer somehow
causes pulseaudio to halt altogether until I kill the python script which
launched the pipeline. Basically once there's an underrun it seems to be
terminal.

As I think you guessed, I was looking for a low-effort way to reduce load,
so I didn't get into rewriting the core logic of the spectrum element. I
was surprised that the CPU load of the FFT doesn't depend on some other
factors like the sample rate, which I might be able to reduce cheaply. For
now, it works, and that's good enough!

Cefn
http://cefn.com
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