How to get audio frequency ?

[sonichy]

I want to draw frequency lines when play QMediaPlayer.

[mrjj]

Hi
maybe this can get you in right direction
http://blog.qt.io/blog/2010/05/18/qtmultimedia-in-action-a-spectrum-analyser/

I think the normal way is via
https://en.wikipedia.org/wiki/Fast_Fourier_transform
(as link also uses)