anxvis: args for color customization
anxvis: make pygame preview optional
also makes text speed scale with video size
anxvis: ignore pygame warnings
if anxvis is run on an avx2 capable machine, pygame will complain about
itself not being compiled with support for avx2 on nix. this will
suppress that warning.
flake: include ffmpeg as dependency
anxvis: fix multi-channel audio
if an audio file contained more than one channel, numpy would declare
it as a NaN when calculating its mean on the row() function. this fixes
the issue by replacing the original input with the mean of all channels
(axis 1).
anxvis: switch to pillow-simd
anxvis: rix rms algorithm
it uselessly calculated it per sample, where as it should be calculating
it per chunk