Local key estimation from an audio signal relying on harmonic and metrical structures

In this paper, we present a method for estimating the progression of musical key from an audio signal. We address the problem of local key finding by investigating the possible combination and extension of different previously proposed approaches for global key estimation. In this work, key progression is estimated from the chord progression. Specifically, we introduce key dependency on the harmonic and the metrical structures. A contribution of our work is that we address the problem of finding an analysis window length for local key estimation that is adapted to the intrinsic music content of the analyzed piece by introducing information related to the metrical structure in our model. Key estimation is not performed on empirically chosen segments but on segments that are expressed in relationship with the tempo period. We evaluate and analyze our results on two databases of different styles. We systematically analyze the influence of various parameters to determine factors important to our model, we study the relationships between the various musical attributes that are taken into account in our work, and we provide case study examples.