Description
It doesn't seem like this visualization.spectrum addon makes use of frequency information for its display.
The CVisualizationSpectrum::AudioData()
function makes no use of pFreqData
or iFreqDataLength
. Instead, a somewhat odd sampling of the amplitude information carried by pAudioData
is used instead:
visualization.spectrum/src/opengl_spectrum.cpp
Lines 455 to 482 in f3dceca
I found mention of this in a kodi.tv forum back in a 2014 thread:
https://forum.kodi.tv/showthread.php?tid=204991&pid=1846424#pid1846424
the spectrum viz doesn't use fft data... there are no vizes in mainline using the fft data. it's still borked, but that is NOT a way to test it.
Wow. No wonder it looks nothing like a spectrum analyser display...
I really think it should be using the fft data (well assuming the fft data is fixed).So it just uses a random subset of audio samples. That would explain why it looks like random noise.
and
well, it's amplitude bins for each data set. so not entirely random but surely not a proper spectrum.