[MEI-L] Music Addressability API draft

[Johannes Kepper]

Hi Raff,

it's great to hear about EMA again, and it seems like you've made a lot of progress (congrats!). There is one question I stumbled upon recently in the Freischütz context, which clearly falls into the scope of EMA as well, and I would like to hear your opinion about it. Since it (in my opinion) is an MEI question, I prefer to discuss it over here, instead of Github. Let's see where it leads us…

Let's assume we're in a simple 4/4 meter, and we want to encode a slur that ranges from the first to the last note in that measure. Now let's look at different examples in this setup. 

1)
We have four quarter notes. Our slur is 
<slur tstamp="1" tstamp2="0m+4"/>

2)
Let's consider we have a hairpin instead, which ranges from the first to the last quarter:
<hairpin tstamp="1" tstamp2="0m+4"/>

3)
Let's consider our hairpin stretches across the full measure, which contains just a whole note:
<hairpin tstamp="1" tstamp2="0m+4"/>

4)
Let's go back to a slur which stretches to the second of two eighth notes on the last beat. Our slur is 
<slur tstamp="1" tstamp2="0m+4.5"/>

5)
What does this mean to 3)? Should it be 
<hairpin tstamp="1" tstamp2="0m+4.5"/>
instead, to indicate that the hairpin really goes to the end of the measure? By definition, in MEI a tstamp="5" (in 4/4) denotes the right barline, so should we use something like "5", or perhaps "4.999" in this situation?

6)
To my understanding, a musical range in MEI should include all events which have an onset (=tstamp) that is between the range's starting tstamp and it's ending tstamp2. 

7)
If 6) is true, a valid encoding for 3) would be
<hairpin tstamp="1" tstamp2="0m+1"/>
This hairpin would cover all notes that start at tstamp="1", which is obviously true for a whole note. 

8)
However, this encoding obviously does not address the (graphical) aspect of the hairpin stretching the whole measure. I'm not sure if this is a problem – it could be addressed with other (more graphical) attributes instead. 

----

It all comes down to the question if 6) is correct, or if a tstamp2 denotes the absolute end of a range. In other words: Does the crescendo stop at the onset of the note at which hairpin/@tstamp2 is pointing, or does it also include the duration of that note (which would make it context dependent…)? In terms of EMA: Would you include the notes that start at the specified ending beat, or would you drop them, since they don't completely fit into the specified range?

I think MEI isn't clear enough on this, on EMA seems to be a perfect opportunity to discuss how people would interpret it, and if we should try to be more explicit on this. 

Best,
jo 




Am 03.11.2014 um 17:11 schrieb Raffaele Viglianti <raffaeleviglianti at gmail.com>:

> Dear List,
> 
> The idea behind the Enhancing Music Notation Addressability (EMA) project is to investigate ways to make it possible to link to specific parts of a music document available online. Being able to do so could be useful to quote passages, express analytical statements and annotations, or passing a selection of music notation on to another process for rendering, computational analysis, etc.
> 
> As part of the project, I've been working on a URL specification to express a selection of music notation based on measure, staves, and beats. I am also writing an API that describes how to process the URL and the music notation. 
> 
> You can find the URL specification and the API documentation here:
> https://github.com/umd-mith/ema/blob/master/docs/api.md
> 
> I am now working on an implementation of the API that works with MEI files. If you have used an image server before, you can imagine how this will work: given a URL specifying a zoom level and a region of an image, the server returns an image of the selected region. Likewise, this MEI-based implementation would return the region of an MEI file, according to the selection specified by the URL.
> 
> I would be very interested in hearing any comments and suggestions that you might have at this stage. Can you imagine that this system may be useful for your projects? Is the URL specification expressive enough? Are there other parameters that you would want the API to include?
> 
> If you are interested, I would encourage you to fork the GitHub repository and contributing!
> 
> Many thanks and all the best,
> Raff
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