libutaust

Parsing and writing UST (UTAU Sequence Text) files in C.

This is one of the subprojects under Synthesizer V that I had to implement in order to make use of the vast amount of community-sourced lyric-embedded music scores for the testing of the said software.

• BSD license.

• No dependency other than the standard library.

• Does not yet support the parsing of attribute Envelope, VBR, etc. These attributes are stored as strings in structure utaust_note.

• Note duration and position are stored in double-precision floating points. Use of utaust_iterator to compute the onset time of a note is recommended since it implements high-accuracy Kahan summation algorithm; accumulated summation/subtraction errors are on the order of O(1). However, errors will accumulate linearly if the calling program switches back and forth between utaust_iterator_next and utaust_iterator_prev.

• You may need to tweak compiler optimization settings if you see an error greater than 1e-15 sec when running the test. I highly doubt if the accumulated error would ever be an issue though, and writing this explanation is taking probably longer than what it took to implement the sum algorithm.