Exporting timing information out of lilypond

[Thomas Tensi]

Hello,


I'm trying to make MPEG-4 notation files from lilypond
output.  Each key frame is a score sheet (a PNG picture)
shown for a specific time, but it has to be synchronous with
the music played (also generated from lilypond).

To achieve that I need a list of play times per sheet and
the total number of sheets produced automatically.

One idea is to have lilypond put out some MIDI meta event
into its generated midi file whenever the page is broken.
When looking at the MIDI generation code, it seems that no
meta events are written at all, are they?

Another idea is to link into the page breaking via some
callback and to write a sequential file with the measures at
page breaks.  Together with the MIDI tempo track this should
help in finding the absolute time positions.

Is this possible or completely nonsensical?


         Best regards,

              Thomas