Support for plica

[grochat]

Following the discussion on ig-mensural list, here is a proposal of encoding for plicas, taking various situations into account:

• second note's pitch is determined
• second note's pitch is undetermined
• under a ligature (typically at its end)

It is a formalization of Karen's proposal with some amendments.

Since the plica is a figure of notes (essentially a neume), I would rather keep the @dur information of the plicated (main) note within <note> rather than moving it to <plica> which is but a container. And the fact that the second note has no @dur attribute reflects well that it is essentially a "grace" note.

What think ye?..
Robert

<!-- plica, determined pitch -->
<layer>
    <plica>
        <note dur="longa" oct="4" pname="d"/>
        <note oct="4" pname="e"/>
    </plica>
</layer>

<!-- plica, undetermined pitch, with @type (=ascending/descending) -->
<layer>
    <plica type="ascending">
        <note dur="brevis" oct="4" pname="d"/>
        <note/>
    </plica>
</layer>

<!-- plica at the end of a ligatura -->
<layer>
    <ligatura>
        <note dur="semibrevis" oct="4" pname="c"/>
        <note dur="semibrevis" oct="4" pname="d"/>
        <note dur="brevis" oct="4" pname="e"/>
        <plica type="ascending">
            <note dur="brevis" oct="4" pname="d"/>
            <note oct="4" pname="e"/>
        </plica>
    </ligatura>
</layer>

[martha-thomae]

From what I can see in the messages exchanged in the mailing list, we agreed on encoding plica as an attribute. Could you, please, rephrase your examples in terms of an attribute? It was definitely the direction the discussion was taking. Look at Karen's examples for encoding the interpretation of the plica (separated from the actual plica) by using the elements <orig> and <reg> within <choice>. I think all the examples you are providing here can be re-phased in terms of @plica and using <choice> with <orig> and <reg>.

[martha-thomae]

Here are Karen's examples (the ones in the google doc) rewritten with the plica encoded as an attribute (@plica), following the discussion in the Mensural-IG Mailing List.

For simple notes:

For our purposes for notae simplices (single notes not ligatures) the encoding would be as follows:

<note dur="longa" oct="5" pname="f" xml:id="n1" plica="desc"/>

And in realization, this:

<choice>
    <orig>
        <note dur="longa" oct="5" pname="f" xml:id="n1" plica="desc"/>
    </orig>
    <reg>
        <note dur="brevis" oct="5" pname="f" xml:id="n1r"/>
        <note dur="brevis" oct="5" pname="e" xml:id="n2r"/>
    </reg>
</choice>

For ligatures:

Here’s the basic encoding:

<ligature>
    <note dur="longa" oct="5" pname="a" xml:id="lig_1_n1"/>
    <note dur="brevis" oct="5" pname="g" xml:id="lig_1_n2"/>
    <note dur="longa" oct="5" pname="f" xml:id="lig_1_n3" plica="desc"/>
</ligature>

And if you want to realize the plica you could have this encoding:

<ligature>
    <note dur="longa" oct="5" pname="a" xml:id="lig_1_n1"/>
    <note dur="brevis" oct="5" pname="g" xml:id="lig_1_n2"/>
    <choice>
         <orig>
              <note dur="longa" oct="5" pname="f" xml:id="lig_1_n3" plica="desc"/>
         </orig>
         <reg>
             <note dur="brevis" oct="5" pname="f" xml:id="lig_1_n4r"/>
             <note dur="brevis" oct="5" pname="e" xml:id="lig_1_n4r" />
        </reg>
    </choice>
</ligature>

[martha-thomae]

Related to neumes:

Also indicated in the document:

In neume module they indicate the ancestor of the place - the liquescent - like this, as an element within a neume), for example:

<neume>
  <nc curve="c" pname="c" oct="4" tilt="n">
    <liquescent/>
  </nc>
</neume>

And this was part of the conversation in the Mensural-IG emails:

We could allow for @plica to be used within the <stem> element, allowing for encoding the length of the stroke. The conversation reads (June 5th, 2020):

The is encoding visual aspects, which Joshua seems to want to do here, whereas I'm more concerned with the semantic implications of knowing that a particular note is a plica (and for that, having plica as an attribute of note is fine).

There seems to be agreement in this proposed solution as can be seen from the answer given (same date).

[grochat]

Thanks for the context, Martha.
I really like the idea in your solution that the plica be just set as a single attribute (and with more verbosity, of course, in the realization).
(My solution, less symbolic, is clearly more verbose but this is because I did not want to lose the "note" nature of the second part of the plica.)

And sorry, by the way: I have just joined the mensural-IG group, and I did not even introduce myself! I am Robert, the developer of the "Medieval" plug-in for Finale, and I am currently adding a MEI-mensural to Medieval/Finale feature. I also work with Laurent Pugin as part of the "Chanter les motets de Philippe de Vitry" project to improve the mensural rendering in verovio (there is a new font, "Machaut", in development...)

[martha-thomae]

Hi Robert!
Very nice to meet you. I am glad you are joining us in the discussion of the encoding of plica. And thanks for submitting an issue with examples, that was the next step in the discussion, so this is perfect!

Nothing to be sorry about :)
I wasn't sure if you were up to date with the whole discussion, so I tried to summarize everything here.

I am glad you are joining the discussion and I am so happy with the news that Finale is going to have a "Medieval" plug-in. This is exciting! Same with the "Machaut" font! Thank you for sharing such great news.

As I said, I was just summarizing what has been discussed here and there (google document, mailing list, personal meeting at MEC, etc). The ideal people for this discussion would be @karend27 and Joshua (not sure which is his username in GitHub, sorry). As of now, both parties to be in agreement with going on the direction of encoding plicas as attributes. Of course, the discussion is open; and the idea is to provide encoding examples to determine the best way of encoding the plica so that a decision can be reached.

So, again, nice meeting you and welcome to the Mensural-IG!

[grochat]

Thanks, Martha! I am really happy to be now better acquainted to the realm of MEI. I surely will have other questions and suggestions.

For information, here is the link to the verovio-mensural fork.
Also, the Medieval Finale plug-in has actually existed for more than 20 years (already!). It is commercial project.

Robert

[martha-thomae]

Thank you very much for the links to these resources. And thanks for the information about the Medieval Finale plug-in, I didn't know about it. Looking forward to play around with it :)

[karend27]

Hi Robert - nice to meet you too and thanks for your comments on the plica. For Vitry, you might have seen the motets we've encoded here: http://www.measuringpolyphony.org.

And sorry, by the way: I have just joined the mensural-IG group, and I did not even introduce myself! I am Robert, the developer of the "Medieval" plug-in for Finale, and I am currently adding a MEI-mensural to Medieval/Finale feature. I also work with Laurent Pugin as part of the "Chanter les motets de Philippe de Vitry" project to improve the mensural rendering in verovio (there is a new font, "Machaut", in development...)