OBRAMUS: A System for Object-Based Retouch of Amateur Music∗

In the more recent past, the area of semantic audio has become object of special attention due to the increase in attractiveness of signal representations which allow manipulations of audio on a symbolic level. The semantics usually refer to audio objects, such as instruments, or musical entities, such as chords or notes. On this view, we present a system for making minor corrections to amateur piano recordings based on a nonnegative matrix factorization. Acting as middleman between the signal and the user, the system enables a simple form of musical recomposition by altering pitch, timbre, onset and offset of distinct notes. The workflow is iterative, that is the result improves stepwise through user intervention.