Transposing scores are always encoded at sounding pitch in Humdrum
data, and instructions for transposing to written pitch are encoded
at the start of the part. In the following example, the second
spine encodes a B-flat clarinet part, with the transposition
*ITrd1c2 meaning that the written part is a diatonic
step up, equivalent to 2 semi-tone up.
See the transposing parts section of the documentation for more information.