MPEG-7 low-level audio descriptors
I just did some research on existing implementations of the MPEG-7 audio descriptors and found the following implementations:


The official implementation of the 17 low-level descriptors (part 1 and part 2) (MATLAB).


Alghough the descriptors are implemented in MATLAB, it should not be a big issue to implement them in Python, based on the MATLAB code. Maybe the following resources are also of interest:


The Timbre Toolbox, which implements a number of features described in this JASA article, which include some of the MPEG-7 audio descriptors (MATLAB) and
An an online computation of all 17 audio descriptors with the MPEG-7 Low Level Descriptor Extractor of the TU Berlin.