MIDI->RTTTL converter for BLHeli_32 and BlueJay Quadcopter ESCs

ConvertTo-Rtttl.ps1

[CmdletBinding()]
param (
    [string]
    $midiFilePath,
    [string]
    $label = "Label",
    [int[]]
    $midiChannels = @(2),
    [int]
    $ticksPerQuarterNote = 192,
    [int]
    $transpose = 0
)

if ($midiFilePath -eq "") {
    $midiFilePath = Get-ChildItem $PWD *.mid | Out-GridView -PassThru | Select-Object -ExpandProperty FullName
}

# get tool at: https://www.fourmilab.ch/webtools/midicsv/#Download
if (Test-Path $midiFilePath) {
    if (!(Test-Path "./Midicsv.exe")) {
        Write-Warning "Midicsv.exe missing. Get it at https://www.fourmilab.ch/webtools/midicsv/#Download and put it next to this script!"
        Read-Host -Prompt "Press any key to quit." | Out-Null

        exit 1
    }
    $midiCsvFilePath = ($midiFilePath + ".csv")
    & ./Midicsv.exe $midiFilePath $midiCsvFilePath
} else {
    Write-Warning "Midi file `"" + $midiFilePath + "`" not found."
    Write-Host "If you need to create/edit a midi file to use, check out http://www.midieditor.org/index.php?category=download"
    Write-Host "For best results, quantize the midi file to 32nd notes or bigger."
    Read-Host -Prompt "Press any key to quit." | Out-Null

    exit 1
}

# write Custom CSV Header for correct labelling of fields:
$customCsvHeaderLine = "MidiChannel, Ticks, Header, TrackId, NoteNumber, Velocity, DurationInTicks, ContributingNoteValues, RtttlNoteName, RtttlNoteNotation"

$midiCsvTxt = Get-Content $midiCsvFilePath
$midiCsvTxt[0] = $customCsvHeaderLine
$midi = $midiCsvTxt | convertfrom-csv

$msPerQuarterNote = ($midi | Where-Object { $_.Header -eq "Tempo" } | Select-Object -ExpandProperty TrackId -First 1) / 1000
$bpm = [int](60 / ($msPerQuarterNote / 1000))
function Get-NoteName {
    param (
        [int]
        $noteNumber,
        [int]
        $transpose
    )
    $noteNames = @("c", "c#", "d", "d#", "e", "f", "f#", "g", "g#", "a", "a#", "b")
    $zeroedNoteNumber = $noteNumber - 12
    $noteName = $noteNames[$zeroedNoteNumber % 12]
    [int] $octave = $zeroedNoteNumber / 12 - 1 + $transpose

    $rttlNoteName = $noteName + $octave

    return $rttlNoteName
}

function Get-ContributingNoteValues {
    param (
        [int]
        $ticks,
        [int]
        $ticksPerQuarterNote
    )
    $noteValues = [string[]]@(
        "1",
        "2.",
        "2", 
        "4.",
        "4",
        "8.",
        "8", 
        "16.",
        "16",
        "32.",
        "32"
    )
    $noteValueTicks = [float[]]@(
        (1 / 1),
        (1 / 2 * 1.5),
        (1 / 2),
        (1 / 4 * 1.5),
        (1 / 4),
        (1 / 8 * 1.5),
        (1 / 8),
        (1 / 16 * 1.5),
        (1 / 16),
        (1 / 32 * 1.5),
        (1 / 32)
    )

    $ticksPerFullNote = $ticksPerQuarterNote * 4
    $contributingNoteValues = [System.Collections.ArrayList]@()

    while ($ticks -gt 0) {
        for ($i = 0; $i -lt $noteValues.count; $i++) {
            if ($ticks -ge ($ticksPerFullNote * $noteValueTicks[$i])) {
                $contributingNoteValues.Add([string]$noteValues[$i]) | Out-Null
                $ticks -= $ticksPerFullNote * $noteValueTicks[$i]
                break
            }
        }

        if ($ticks -lt ($ticksPerFullNote * $noteValueTicks[-1])) {
            if ($ticks -gt 0) {
                Write-Warning ("Tick unresolved. Remainder:" + $ticks)
            }
            break
        }
    }
    
    return @($contributingNoteValues)
} 

function Get-RtttlNoteNotation {
    param (
        [string]
        $noteName,
        [string[]]
        $contributingNoteValues
    )
    return ($contributingNoteValues | ForEach-Object { return ($_ + $noteName) -replace "(\d+)(\.)(\w\d*)", '$1$3$2' }) -join ","
}

[System.Collections.ArrayList]$finalNotes = [System.Collections.ArrayList]@(
    [System.Collections.ArrayList]@(),
    [System.Collections.ArrayList]@(),
    [System.Collections.ArrayList]@(),
    [System.Collections.ArrayList]@()
)

$notes = $midi | Where-Object { $midiChannels.Contains([int]$_.MidiChannel) -and ($_.Header -eq "Note_on_c" -or $_.Header -eq "Note_off_c") }
foreach ($note in $notes) {
    $note.Ticks = [int]$note.Ticks
    $note.Velocity = [int]$note.Velocity
    # note on events
    if ($note.Velocity -ne 0) {
        $track = -1

        for ($i = 0; $i -lt $finalNotes.Count -and $track -eq -1; $i++) {
            $queriedNote = $finalNotes[$i][-1]
            if ((-not $finalNotes[$i].Count -or $queriedNote.durationInTicks) -and $queriedNote.NoteNumber -eq $note.NoteNumber) {
                $track = $i
            }
        }

        for ($i = 0; $i -lt $finalNotes.Count -and $track -eq -1; $i++) {
            $queriedNote = $finalNotes[$i][-1]
            if (-not $finalNotes[$i].Count -or $queriedNote.durationInTicks) {
                $track = $i
            }
        }

        if ($track -gt -1) {
            $note.RtttlNoteName = Get-NoteName $note.NoteNumber $transpose

            $previousNoteEndInTicks = 0
            if ($finalNotes[$track].Count) {
                $previousNote = $finalNotes[$track][-1]
                if ($previousNote.NoteNumber -eq $note.NoteNumber) {
                    $previousNote.DurationInTicks -= $ticksPerQuarterNote * 4 * 1 / 32 # subtract 32nd note
                    $previousNote.ContributingNoteValues = (Get-ContributingNoteValues $previousNote.DurationInTicks $ticksPerQuarterNote)
                    $previousNote.RtttlNoteNotation = (Get-RtttlNoteNotation $previousNote.RtttlNoteName $previousNote.ContributingNoteValues)
                }
                $previousNoteEndInTicks = ($previousNote.Ticks + $previousNote.DurationInTicks)
            }

            $pauseLengthInTicks = $note.Ticks - $previousNoteEndInTicks

            if ($pauseLengthInTicks) {
                $pauseValues = @(Get-ContributingNoteValues $pauseLengthInTicks $ticksPerQuarterNote)
                $rtttlPause = (Get-RtttlNoteNotation "p" $pauseValues)
                $finalNotes[$track].Add([PSCustomObject]@{
                        Ticks             = $previousNoteEndInTicks
                        RtttlNoteNotation = $rtttlPause
                    }) | Out-Null
            }
            $finalNotes[$track].Add($note) | Out-Null
        }

    }
    # note off events
    else {
        $track = -1

        for ($i = 0; $i -lt $finalNotes.Count -and $track -eq -1; $i++) {
            $queriedNote = $finalNotes[$i][-1]
            if ($queriedNote.NoteNumber -eq $note.NoteNumber -and -not $queriedNote.durationInTicks) {
                $track = $i
            }
        }

        if ($track -gt -1) {
            $releasedNote = $finalNotes[$track][-1]
            $releasedNote.DurationInTicks = $note.Ticks - $releasedNote.Ticks + 1
            $releasedNote.ContributingNoteValues = @(Get-ContributingNoteValues ($releasedNote.DurationInTicks) $ticksPerQuarterNote)
            $releasedNote.RtttlNoteNotation = (Get-RtttlNoteNotation $releasedNote.RtttlNoteName $releasedNote.ContributingNoteValues)
        }
    }
}

$rttl = $finalNotes | ForEach-Object {
    $label + ":" + "b=" + $bpm + ",o=4,d=32:" + (($_.RtttlNoteNotation) -join ",")
}

Write-Host "Copy the following melodies to your Quad via https://esc-configurator.com/"
Write-Host ($rttl -join "`n`n")