Re: calculating durations

[Erik Sandberg]

On Thursday 15 September 2005 20.48, address@hidden wrote:
> Hi all,
>
>   I am a new user of LilyPond and I am currently writing a program that
> transforms scores expressed in a piano-roll-like format into LilyPond
> scores, for the purpose of typesetting/printing.
>
>   In the source format, music is expressed (like Midi, I suppose) as
> strings of notes with absolute durations, without a notion of time
> signatures, barlines, ties, etc.  Is there a tried-and-true algorithm
> for converting such "notes" into their proper equivalents in LilyPond,
> given a time signature?

I have 2 ideas:
- You could go through MIDI (i.e. let your program convert from 
piano-roll-format to MIDI), and use lilypond's midi2ly program to create 
the .ly file
- If you are familiar with python, write a piano-roll-to-.ly converter based 
on midi2ly.py. In this case, you may only distribute the converter under the 
terms of the GNU GPL.

>   I'm especially thinking of how to resolve a note like "c3" (where 3
> means 3 quarter note beats) into Lilypond's "c2."  Any suggestions?  I
> suppose this problem relates to "quantization" but in this case, the
> input data is mostly "clean" and unambiguous.  I don't think the
> solution should be too compilcated.

This is done by midi2ly, so both the above solutions would fix this.

-- 
Erik