MATCH: A Music Alignment Tool Chest

We present MATCH, a toolkit for aligning audio recordings of different renditions of the same piece of music, based on an efficient implementation of a dynamic time warping algorithm. A forward path estimation algorithm constrains the alignment path so that dynamic time warping can be performed with time and space costs that are linear in the size of the audio files. Frames of audio are represented by a positive spectral difference vector, which emphasises note onsets in the alignment process. In tests with Classical and Romantic piano music, the average alignment error was 41ms (median 20ms), with only 2 out of 683 test cases failing to align. The software is useful for content-based indexing of audio files and for the study of performance interpretation; it can also be used in real-time for tracking live performances. The toolkit also provides functions for displaying the cost matrix, the forward and backward paths, and any metadata associated with the recordings, which can be shown in real time as the alignment is computed.