* Resolved an issue with the ESP8266 where gamma correction would be
performed twice. Changed GAMMA_CORRECTION to SOFTWARE_GAMMA_CORRECTION
to make a distinction between software and firmware gamma correction.
The ESP8266 does firmware gamma correction and dithering, while the
Raspberry Pi uses slightly more inferior software gamma correction.
Changed the software gamma table to match the gamma table used in the
ESP8266 firmware.
* Improved the spectrum visualization by using one of the color channels
to visualize the absolute value of the temporal derivative of the
spectrum. Also added a feature to reject the "common mode" spectral
components, which is analogous to the spectral DC component.
* Signficantly improved the GUI and added a frequency adjustment slider.
Adjusting the frequency range has a big impact on the visualization
output. Recommend using a high frequency range (something like 4 kHz -
10 kHz) when running the scrol visualization.
This commit adds support for the Raspberry Pi, which allows users to
create a completely standalone music visualization system. The Raspberry
Pi should be connected directly to a ws2812b LED strip. A PWM-capable
GPIO pin should be connected to the data line of the LED strip. A USB
audio input device should be connected to one of the Raspberry Pi's USB
ports.
It is recommended that the GUI and FPS output be disabled when running
the visualization on the Raspberry Pi. These features can degrade
performance on the already computationally limited Raspberry Pi.
Changes to config.py:
> Increased STFT rolling window size
> Added configurable options for setting the max and min FFT frequency
Changes to dsp.py:
> Significantly improved the normalized weighted phase deviation code.
This noticeably improves the onset detection accuracy.
> Logarithmic partitioning of the FFT bins now happens after onset
detection instead of before onset detection. This improves onset
detection accuracy at the expense of CPU time.
> Fixed a bug in the log_partition function which would sometimes cause
out of bounds errors
> Refactored and removed some functions that aren't needed anymore
Changes to sandbox.py:
> Sweeping changes to the visualization functions. The onset detection
functions are now combined after applying Gaussian blur to each onset
function individually. This improves the overall agreement between the
onset functions.
> Hyperbolic tan function is used to map saturated pixels to the range
[0, 1]
> Added a new rainbow generation function with more options than the old
one.
> Refactored most of the led update functions.
> The LED brightness is now being plotted instead of onsets
* Moved all module settings to a new config.py file
* Completely overhauled visualize.py and added a new radiate effect that
colours the radiative beats according the beat frequency.
* Improved some constants like the decay constant to be parametric so
that they scale to any led strip size
* Added temporal dithering to Beat.update_pixels() so that it now
supports fractional speed values. Being limited to integral values was
starting to become a problem.
* Overhauled and simplified the LED module.
* When updating pixels, the LED module no longer sends UDP packets for
pixels that have not changed. This optimization reduces the packet load
significantly and should allow for higher refresh rates.
* Renamed lookup_table.npy to gamm_table.npy to better reflect that the
table is used for gamma correction of the LED strip
