Encoding metrical times and durations in scores

[jonnybluesman]

Representing and manipulating metrical times

Main discussion thread to address the need of representing metrical duration consistently.

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Currently, as a temporary workaround to keep the original JAMS (audio) structure, we are collapsing [measure, offset] in a single value that can be used for the time (start) field. Duration is represented accordingly, but: (i) may not be consistent when time signature changes occur; (ii) may not support mathematical operations in base 10 when the offset is expressed in beats (e.g. 1.4 is almost 2 in 4/4).