Here is a snippet on how to play with the **fix_fft** in winamp. The reason for this is, it gives a good idea if it's worth the effort to implement in the Esp8266 ( which I think it is ;-). It's just a quick & dirty hack... to get a feeling.

Current goal :

* Sample with Esp8266 ADC in approximate 10kHz

* 8 bit fix_fft: 16 fft bin is enough ( but I'll probably calculate more, or use a filter ;-)

* Predict beat

Track active frequencies with histogram - predict beat

This-Is-Your-Brain-On-Music

A different way to visualize rhythm - John Varney

Beat detection C++

Beatbots

* Make something fun..."synchronized party stuff"

Download Video as MP4

// http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=960&lngWId=3
// By: David Overton
// vis_spectrum.cpp
winampVisModule waModule = {
...
1, // spectrumNch
1, // waveformNch
...
};
char g_real[600];
char g_imag[600];
OnPluginRender
int n=0;
for( int i=0; i<576; i+=4 /* play with sample rate 1-9 */)
{
g_real[n]=mod->waveformData[0][i];
++n;
}
fix_fft(g_real, g_imag, 6, 0);
for (int i=0; i<32/* number of bins = FFT points/2 */; i++)
{
// just a "scale factor" not much thought put into it.....
g_real[i] = 8.6*( (sqrt((float)g_real[i] * (float)g_real[i] + (float)g_imag[i] * (float)g_imag[i])));
}
HBRUSH NewBrush = CreateSolidBrush(RGB(255, 255, 255));
HBRUSH hbrushOld = (HBRUSH)SelectObject(Plugin.hMemDC, NewBrush);
int x=7;
int y;
/* just hard coded values without respect of actual size */
for( int i=0; i<16/* number of bins to display*/; ++i )
{
y=118-g_real[i];
if( y<8 )
y=8;
Rectangle(Plugin.hMemDC, x, y, x+16, 118);
x+=16; /* bar width*/
}
SelectObject(Plugin.hMemDC, hbrushOld);
DeleteObject (NewBrush) ;
..... // Blit all to hDC

i think APA107 LED source is better choice

Datasheet: https://issuu.com/newstarleds/docs/apa107_led