Incorrect mRest duration assumption leads to pause in generated audio #1453
Comments
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The problem here is that a It should be: |
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@wergo the condition is correct. If you reimport the file into MuseScore (where it came from), it shows a whole measure rest too. |
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Should we really base an argument on the MusicXML import capabilities of MuseScore, that often that it is faulty? The xml pertinent snipped is this (with <measure number="4" width="171.46">
<print new-system="yes"/>
<note>
<rest/>
<duration>4</duration>
<voice>1</voice>
</note>
</measure>So, the |
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The musicxml specifies a whole measure rest (because type is undefined), and the whole measure is 1 quarter-note long. So I think we should create an mRest with dur and dur.ppq set appropriately... |
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Putting |
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@lpugin this is not an MusicXML issue, but one about mRest duration calculation. |
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(The MEI posted in #1481 does not contain any The result of the MusicXML conversion of the example above leaves me doubtful: <measure xml:id="measure-0000000347293321" right="invis" n="3">
<staff xml:id="staff-0000000269333995" n="1">
<layer xml:id="layer-0000000010344056" n="1">
<note xml:id="note-0000001551771701" dur.ppq="8" dur="2" oct="4" pname="g" stem.dir="up">
<verse xml:id="verse-0000000177835352" n="1">
<syl xml:id="syl-0000000247952080" con="d" wordpos="i">heav</syl>
</verse>
</note>
<note xml:id="note-0000000232489823" dur.ppq="4" dur="4" oct="4" pname="e" stem.dir="up">
<verse xml:id="verse-0000000941134656" n="1">
<syl xml:id="syl-0000001224484950" con="s" wordpos="t">en,</syl>
</verse>
</note>
</layer>
<layer xml:id="layer-0000000452441359" n="2">
<note xml:id="note-0000001851782662" dur.ppq="8" dur="2" oct="4" pname="e" stem.dir="down" />
<note xml:id="note-0000001886512702" dur.ppq="4" dur="4" oct="4" pname="c" stem.dir="down" />
</layer>
</staff>
<staff xml:id="staff-0000000494954418" n="2">
<layer xml:id="layer-0000000075432589" n="1">
<note xml:id="note-0000000324438461" dur.ppq="8" dur="2" oct="4" pname="c" stem.dir="up" />
<note xml:id="note-0000001459657811" dur.ppq="4" dur="4" oct="3" pname="g" stem.dir="up" />
</layer>
<layer xml:id="layer-0000000430161242" n="2">
<note xml:id="note-0000000937456504" dur.ppq="8" dur="2" oct="3" pname="c" stem.dir="down" />
<note xml:id="note-0000001052792774" dur.ppq="4" dur="4" oct="3" pname="c" stem.dir="down" />
</layer>
</staff>
</measure>
<sb xml:id="sb-0000000828106355" />
<measure xml:id="measure-0000001298228642" n="4">
<staff xml:id="staff-0000000890427094" n="1">
<layer xml:id="layer-0000000777033468" n="1">
<beam xml:id="beam-0000000906894824">
<note xml:id="note-0000001327870263" dots="1" dur.ppq="3" dur="8" oct="4" pname="g" stem.dir="up">
<verse xml:id="verse-0000000829096040" n="1">
<syl xml:id="syl-0000000336840856" con="s">what</syl>
</verse>
</note>
<note xml:id="note-0000000744896718" dur.ppq="1" dur="16" oct="4" pname="g" stem.dir="up">
<verse xml:id="verse-0000000803708960" n="1">
<syl xml:id="syl-0000001374662137" con="s">a</syl>
</verse>
</note>
</beam>
</layer>
</staff>
<staff xml:id="staff-0000001747086282" n="2">
<layer xml:id="layer-0000001383504811" n="1">
<mRest xml:id="mrest-0000000479382709" />
</layer>
</staff>
</measure>So, yes, the mRest calcutation in the MIDI output is wrong, but before we tweak it we need to make sure that this is an appropriate MEI encoding. I am not. |
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Consider the following example. The length of each measure changes. Adding notes works fine, but removing them adds an extra pause from the mRest in the second line. (Note, that no meter is given!) The problem in #1481 basically is the same: We have something that looks like a whole measure, while the <?xml version="1.0" encoding="UTF-8"?>
<?xml-model href="https://music-encoding.org/schema/4.0.0/mei-all.rng" type="application/xml" schematypens="https://relaxng.org/ns/structure/1.0"?>
<?xml-model href="https://music-encoding.org/schema/4.0.0/mei-all.rng" type="application/xml" schematypens="https://purl.oclc.org/dsdl/schematron"?>
<mei xmlns="https://www.music-encoding.org/ns/mei" meiversion="4.0.0">
<meiHead>
<fileDesc>
<titleStmt>
<title />
<respStmt />
</titleStmt>
<pubStmt />
</fileDesc>
</meiHead>
<music>
<body>
<mdiv>
<score>
<scoreDef>
<staffGrp>
<staffDef n="1" lines="5" ppq="1" clef.shape="G" clef.line="2" key.sig="2s">
<label>Violin</label>
</staffDef>
<staffDef n="2" lines="5" ppq="1" clef.shape="G" clef.line="2" key.sig="2s">
<label>Violin</label>
</staffDef>
</staffGrp>
</scoreDef>
<section>
<pb />
<measure>
<staff n="1">
<layer n="1">
<note dur.ppq="1" dur="4" oct="4" pname="c" accid.ges="s" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<rest dur.ppq="1" dur="4" />
</layer>
</staff>
<tempo place="above" staff="1" tstamp="1.000000" mm="92" mm.unit="4" />
</measure>
<measure n="1">
<staff n="1">
<layer n="1">
<note dur.ppq="1" dur="4" oct="4" pname="d" />
<note dur.ppq="1" dur="4" oct="4" pname="f" accid.ges="s" />
<note dur.ppq="1" dur="4" oct="4" pname="a" />
<note dur.ppq="1" dur="4" oct="4" pname="b" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<mRest />
</layer>
</staff>
</measure>
<measure n="2">
<staff n="1">
<layer n="1">
<note dur.ppq="1" dur="4" oct="4" pname="a" />
<note dur.ppq="1" dur="4" oct="4" pname="f" accid.ges="s" />
<note dur.ppq="1" dur="4" oct="4" pname="d" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<mRest />
</layer>
</staff>
</measure>
<measure n="3">
<staff n="1">
<layer n="1">
<note dur.ppq="1" dur="4" oct="4" pname="e" />
<note dur.ppq="1" dur="4" oct="4" pname="g" />
<note dur.ppq="1" dur="4" oct="4" pname="b" />
<note dur.ppq="1" dur="4" oct="5" pname="d" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<mRest />
</layer>
</staff>
</measure>
<measure n="4">
<staff n="1">
<layer n="1">
<note dur.ppq="1" dur="4" oct="5" pname="f" accid.ges="s" />
<note dur.ppq="1" dur="4" oct="5" pname="a" />
<note dur.ppq="1" dur="4" oct="5" pname="f" accid.ges="s" />
<note dur.ppq="1" dur="4" oct="5" pname="d" />
<note dur.ppq="1" dur="4" oct="4" pname="b" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<mRest />
</layer>
</staff>
</measure>
<measure n="5" metcon="false">
<staff n="1">
<layer n="1">
<note dur.ppq="1" dur="4" oct="4" pname="a" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<rest dur.ppq="1" dur="4" />
</layer>
</staff>
</measure>
</section>
</score>
</mdiv>
</body>
</music>
</mei>NB: A general break however would have to rely on a given meter. |
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Yes, to make your example complete, I would expect to have <scoreDef meter.unit="4" meter.count="3" meter.form="invis"/>with appropriate values and whenever necessary, wouldn't you? (PS there are no |
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(To help understanding) |
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To me it looks more like a |
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As I said, "with appropriate values", so I gave the example for measure 2 (the measure with
I am confused: are you talking about <?xml version="1.0" encoding="UTF-8"?>
<?xml-model href="https://music-encoding.org/schema/4.0.0/mei-all.rng" type="application/xml" schematypens="https://relaxng.org/ns/structure/1.0"?>
<?xml-model href="https://music-encoding.org/schema/4.0.0/mei-all.rng" type="application/xml" schematypens="https://purl.oclc.org/dsdl/schematron"?>
<mei xmlns="https://www.music-encoding.org/ns/mei" meiversion="4.0.0">
<meiHead>
<fileDesc>
<titleStmt>
<title />
<respStmt />
</titleStmt>
<pubStmt />
</fileDesc>
</meiHead>
<music>
<body>
<mdiv>
<score>
<scoreDef>
<staffGrp>
<staffDef n="1" lines="5" ppq="1" clef.shape="G" clef.line="2" key.sig="2s">
<label>Violin</label>
</staffDef>
<staffDef n="2" lines="5" ppq="1" clef.shape="G" clef.line="2" key.sig="2s">
<label>Violin</label>
</staffDef>
</staffGrp>
</scoreDef>
<section>
<measure n="1">
<staff n="1">
<layer n="1">
<note dur="4" oct="4" pname="d" />
<note dur="4" oct="4" pname="f" accid.ges="s" />
<note dur="4" oct="4" pname="a" />
<note dur="4" oct="4" pname="b" />
</layer>
</staff>
<staff n="2">
<layer n="1">
<rest dur="1" dur.ges="4"/>
<note dur="2" dots="1" oct="4" pname="d" />
</layer>
</staff>
</measure>
</section>
</score>
</mdiv>
</body>
</music>
</mei>
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Ok. I'm talking about mRests. |
It might be unquestionable in that example, but what if the notes in measure Since the MusicXML has the duration, I think we should try to use that. (Which would also make the conversion less lossy). (This doesn't mean that we shouldn't try to improve mRest duration calculation, just know that doing so won't solve all potential issues.) Next Steps:
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In the following MEI file, there is an mRest in the bass clef of a shortened measure.
When the audio is played back, it pauses for three extra beats, so there is a gap of silence between "what a" and "day". Measure 4 should be only one beat long, so the mRest should only be 1 beats. (Though I don't know how it ought to know that).
This was converted from musicXML:
MusicXML
MEI
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