[MEI-L] Fwd: MEI Customisation

[Andrew Hankinson]

Hi James,

I'm forwarding your message to the W3C list to MEI-L to answer your questions. I don't really want to spam their list...

I'll answer inline below, prefixed with AH for my responses.


> Hi Zoltan, All,
> 
>> Tido's recently published MEI customization <http://tido.github.io/mei-customization/> sparked a lively discussion...
> and
>> For more information on MEI Go! please keep an eye on the MEI-L mailing list for updates <https://lists.uni-paderborn.de/pipermail/mei-l/2016/001796.html> and discussions. While it may not be the solution that the Community Group is looking for, I would like to draw attention to this effort as point of reference.
> 
> I joined the MEI-L mailing list yesterday.
> MEI customization <http://tido.github.io/mei-customization/> says
>> We hope that this customisation can also be the starting point for a common basic MEI customisation to be shared between several projects in future. We welcome comments and suggestions through GitHub issues.
> I've decided to post my comments and suggestions (questions actually) here, rather than on GitHub. Please repost there and/or to MEI-L if you think that's a good idea.
> 
> I'm a beginner with MEI customisation, and need some help:
> 
> Briefly: My problem with current encodings of CWMN is that they all assume that duration symbols have fixed meanings in a score, and that measures therefore "add up" at the symbol level. This ignores the performance practice tradition that is always associated with any humanly readable notation. In Mozart, for example, the last quaver under a slur is never played in the same way as the first. Ignoring performance practice traditions goes back at least to the invention of the metronome in the 19th century. I'm old enough to remember how awful the first computer renditions of Bach sounded in the early 1980s...
> I also think that the famous collapse around 1900 had more to do with the disintegration of fixed tempi, than with the exhaustion of harmonic possibilities. The notation collapsed because the conventions make no sense in the absence of humanly perceptible tempo.

AH: MEI makes no such assumptions. For rhythm and duration we differentiate between "@dur" (written duration) and "@dur.ges" (performed duration). Both of these are available on note and rest objects.

> 
> Whether this analysis is correct or not is, however, immaterial. :-)
> 
> I want to make an MEI customisation that uses most of the symbols that are used by CWMN, but without assuming tempo. If there is no tempo, then neither tuplets nor grace-notes make sense. It should also be possible for the description of more than one temporal instantiation to be stored inside the XML elements that represent the score's graphics.

AH: I'm not sure I understand this. Tempo is generally expressed by a playback mechanism. It can be hinted at in the encoding, but most systems have controls for overriding it. 

> I think that CWMN (as defined by both MusicXML and your project) could be regarded as a superset of such a customisation. If the default temporal realisation of such a score defined all the duration symbols to have fixed meanings, then <measures> could be made to add up at the symbol level by adding tuplet symbols (as annotations) and turning some notes into grace-notes.

AH: We like to think of it in the opposite: MEI is a superset of everything that is possible in notation, while CWMN is one subset of this. 

I'm really not sure where you're going with the duration symbols and fixed meanings, though. Why would you be adding gracenotes and tuplets?

> 
> One advantage of having a tempo-less customisation would be that lossless transcriptions of recordings can be made, without going through "quantisation". I compose with milliseconds...

AH: MEI doesn't assume tempo. In fact, MEI doesn't assume anything. The "@dur.ges" attribute on note objects allows you to record duration on "time-consuming" elements (primarily notes and rests) in terms of "ppq (MIDI clicks and MusicXML 'divisions'), Humdrum **recip values, beats, seconds, or mensural duration values."

> 
> So my initial questions are:
> 1. Can <measure> elements be redefined so that they do not have to add up at the symbol level? The different <layer>s in the measure must however add up in real time (milliseconds) in any one temporal realisation stored in the score.

AH: Yes-ish. Measures do not have a performed duration, they're just assumed to be the performed duration of the "time-consuming" child elements.

> 2. Can you imagine such a hierarchy of customisations? I'm also thinking of the container hierarchy that could become part of the W3C standard for describing any polyphonic music notation.

AH: A customization is not arranged in a hierarchy. The primary reason for a customization is to produce a schema that will validate an encoding. 

> 
> All the best,
> James
> 
> -- 
> http://james-ingram-act-two.de <http://james-ingram-act-two.de/>
> https://github.com/notator <https://github.com/notator>

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