metadata help doc

[seunggookim]

metadata of a sequence (coded_vec) contains $keysig (a signed integer) and $mode (integer, mostly 0 or 9?) but their mappings are not explained anywhere. It would be useful if I can use $keysig to transpose pitch class chords with respect to a reference pitch class (e.g., C=0) but the relationship between the $keysig value and the actual key is unclear (e.g., 'bach-chor001', which seems to be Riemenschneider No.1 (BWV 269), has a $keysig=1 but is in G major. A clear explanation would be much appreciated.

[seunggookim]

Now I think $keysig is the number of sharps in a positive integer or the number of flats in a negative integer (e.g., For F major, $keysig=-1, $mode=0). A very interesting notation! Is there a function to convert this into a pitch class code?