Solved by vincentqb in post #2 
              
              
                The conventions we use for dimensions are given in the README. In particular, a waveform is (channel, time), and MFCC : (channel, time) -> (channel, mfcc, time), and so MFCC is applied per channel. Your original waveform must therefore have had 2 channels. 
In the datasets we provide, the number of …