Author Topic: Adaptive styles (for nerds)  (Read 1471 times)

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Offline pjd

Adaptive styles (for nerds)
« on: August 10, 2021, 12:37:16 AM »
Thanks to Mark, I tool a quick look at the internals of an adaptive style.

The basic MIDI, CASM and OTS sections are there. I didn't find any MIDI magic like unknown SysEx or meta-data. I'm guessing the CASM and OTS chunks are the same format as before. (Emphasis on the word guess. There is too much to check.)

Yamaha added a new chunk type "Cmbi" which is a peer to the MIDI, CASM and OTS chunks. This is probably the honey-pot.

A Cmbi chunk has two major subsections: Main and Fill In. Each subsection has sixteen subchunks: CmSy or CmSp. There are thirteen CmSy subchunks -- same number as the adaptive section variations. Of course, the hard part, what do the CmSy data encode? The CmSp subchunks appear to unused spacers to round thirteen slots up to sixteen slots.

Unless software knows how to decode the Cmbi chunk, it should play the style in the regular, non-adaptive fashion.

Hope this helps somebody -- pj
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