FS#12824 - Malfunctioning FFT plugin in Sansa Clip Zip

Attached to Project: Rockbox
Opened by Tomasz Papiez (electric_indigo) - Thursday, 14 February 2013, 15:30 GMT
Last edited by Michael Sevakis (MikeS) - Friday, 22 February 2013, 01:22 GMT
Task Type Bugs
Category Plugins
Status Closed
Assigned To No-one
Operating System Sansa AMSv2
Severity Low
Priority Normal
Reported Version Daily build (which?)
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No


Since December 2012 (or January 2013, I can't remember) the FFT plugin for Sansa Clip Zip displays constant, excessive levels in two separate, narrow bands, whereas for all other frequencies the shown level is zero. It happens regardless of sound changes, type of scale (linear/log), type of window or chosen view.
This task depends upon

Closed by  Michael Sevakis (MikeS)
Friday, 22 February 2013, 01:22 GMT
Reason for closing:  Fixed
Additional comments about closing:  5fc82f0
Comment by Rafaël Carré (funman) - Wednesday, 20 February 2013, 17:07 GMT
Culprit found:

commit a6409c868663a90673147e6f778ea310f08d4f24
Author: Michael Sevakis <>
Date: Tue Dec 18 20:32:23 2012 -0500

Adapt FFT plugin to use floating on-screen display.

Helps appearance especially with the spectrogram view since it no longer
must be scrolled out of the way to avoid artifacts.

Additionally, allow settings to be saved and clean up some misellaneous
stuff to help graphics performance.

Still other "pointless" work to do on it... :-)

Change-Id: Iff2f725b0237ffb430e85f591675c2062b159abc

apps/plugins/fft/fft.c | 1235 +++++++++++++++++++++++++++++++++++++++----------------------------------
1 file changed, 652 insertions(+), 583 deletions(-)

Note: this commit also makes the zip sim crash when loading fft
Comment by Michael Sevakis (MikeS) - Wednesday, 20 February 2013, 19:16 GMT
Where does it crash? Is there anything peculiar about the clip zip display?
Comment by Michael Sevakis (MikeS) - Friday, 22 February 2013, 00:07 GMT
The sim produces these errors always:
SDL_WaitEvent() error
Segmentation fault

I get this stuff with stack issues. MPEGPlayer won't run in the sim and produces similar obnoxiousness unless thread stacks are larger. I haven't any other ideas at the moment.

Straight git build never shows anything. Removing kiss_fft call on line 1042 allows me to view the lines and bars but it still crashes the sim on spectrogram view.
Comment by Michael Sevakis (MikeS) - Friday, 22 February 2013, 01:09 GMT
LOL...silly me. I forgot to init the plot varable when FFT_FREQ_SCALE key is not defined. Will fix. Will also assign a key for it the this target. (Still needs it for many targets)