Fast way to Delete MIDI Notes from specific channel

[daniellumertz]

Hi People I am using in my MIDI Transfer script a function to delete MIDI Notes with the objective to solo a Channel.

The problem is that it is too slow for huge amount of MIDI it takes a lot of time.

In my test a item with 5600 MIDI notes took 10 second to run. I need to run this more than one time in the script so...

I am wondering if there is a better solution. Here the function I am using

 
function SoloChannel(take, ch) 
    local retval, notecnt, ccevtcnt, textsyxevtcnt = reaper.MIDI_CountEvts( take )
    --NOTES
    for i = notecnt, 1, -1  do
        local retval, selected, muted, startppqpos, endppqpos, chan, pitch, vel = reaper.MIDI_GetNote(take, i-1)
        if ch ~= 0 and chan ~= (ch-1) then
            reaper.MIDI_DeleteNote(take, i-1)
        end
    end
    --CC
    for i = ccevtcnt, 1, -1  do
        local retval, selected, muted, ppqpos, chanmsg, chan, msg2, msg3 = reaper.MIDI_GetCC( take, i-1 )
        if ch ~= 0 and chan ~= (ch-1) then
            reaper.MIDI_DeleteCC( take, i-1 )
        end
    end
end

[Malfunction]

function deletechannel(ch) 
    local gotAllOK
    local MIDIstring 
    gotAllOK, MIDIstring = reaper.MIDI_GetAllEvts(take, "") 
    MIDIlen = MIDIstring:len()  
    tableEvents = {}  
    stringPos = 1  
 
    while stringPos < MIDIlen do 
       offset, flags, ms, stringPos = string.unpack("i4Bs4", MIDIstring, stringPos) 
       if ms:len() == 3 and (ms:byte(1)>>4 == 9 or ms:byte(1)>>4 == 8) then 
        channel = ms:byte(1)&0x0F 
        if channel == ch-1 then ms="" end 
       end 
       table.insert(tableEvents, string.pack("i4Bs4", offset, flags, ms))  
    end 
    reaper.MIDI_SetAllEvts(take, table.concat(tableEvents)) 
 end 

hwnd = reaper.MIDIEditor_GetActive()
take = reaper.MIDIEditor_GetTake(hwnd)
deletechannel(1)

[juliansader]

As Malfunction advised, MIDI_Get/SetAllEvts is the fastest way to edit many thousands of events. However, if you prefer to use the older functions MIDI_Delete/SetNote/CC, then you should always use MIDI_DisableSort at the start, and MIDI_Sort at the end. This will speed up your script by orders of magnitude. (When using DisableSort, take into account that your note and CC indices will not change while you edit them.)

[daniellumertz]

hey thanks people for the suggestions I made some bench here:

 
function SoloChannel(ch) 
    local retval, MIDIstring = reaper.MIDI_GetAllEvts(take, "") 
    local MIDIlen = MIDIstring:len()
    local tableEvents = {}
    local stringPos = 1
    --local pos=0 
    while stringPos < MIDIlen do 
        offset, flags, ms, stringPos = string.unpack("i4Bs4", MIDIstring, stringPos) -- Unpack the MIDI[stringPos] event 
        --pos=pos+offset -- For keeping track of the Postion of the notes in Ticks
        if ms:len() == 3 and (ms:byte(1)>>4 == 9 or ms:byte(1)>>4 == 8) then -- if ms:len == 3 means it have 3 messages(Notes, CC,Poly Aftertouch, Pitchbend )  (ms:byte(1)>>4 == 9 or ms:byte(1)>>4 == 8) note on or off
            local channel = ms:byte(1)&0x0F -- 0x0F = 0000 1111 in binary . ms is decimal. & is an and bitwise operation "have to have 1 in both to be 1". Will return channel as a decimal number
            if channel ~= ch-1 then ms="" end 
        end 
        table.insert(tableEvents, string.pack("i4Bs4", offset, flags, ms))
    end 
    reaper.MIDI_SetAllEvts(take, table.concat(tableEvents)) 
end 


function SoloChannelSort(take, ch) 
    reaper.MIDI_DisableSort( take )
    local retval, notecnt, ccevtcnt, textsyxevtcnt = reaper.MIDI_CountEvts( take )
    --NOTES
    for i = notecnt, 1, -1  do
        local retval, selected, muted, startppqpos, endppqpos, chan, pitch, vel = reaper.MIDI_GetNote(take, i-1)
        if ch ~= 0 and chan ~= (ch-1) then
            reaper.MIDI_DeleteNote(take, i-1)
        end
    end
    --CC
    for i = ccevtcnt, 1, -1  do
        local retval, selected, muted, ppqpos, chanmsg, chan, msg2, msg3 = reaper.MIDI_GetCC( take, i-1 )
        if ch ~= 0 and chan ~= (ch-1) then
            reaper.MIDI_DeleteCC( take, i-1 )
        end
    end
    reaper.MIDI_Sort( take )
end


function SoloChannelNoSort(take, ch) 
    local retval, notecnt, ccevtcnt, textsyxevtcnt = reaper.MIDI_CountEvts( take )
    --NOTES
    for i = notecnt, 1, -1  do
        local retval, selected, muted, startppqpos, endppqpos, chan, pitch, vel = reaper.MIDI_GetNote(take, i-1)
        if ch ~= 0 and chan ~= (ch-1) then
            reaper.MIDI_DeleteNote(take, i-1)
        end
    end
    --CC
    for i = ccevtcnt, 1, -1  do
        local retval, selected, muted, ppqpos, chanmsg, chan, msg2, msg3 = reaper.MIDI_GetCC( take, i-1 )
        if ch ~= 0 and chan ~= (ch-1) then
            reaper.MIDI_DeleteCC( take, i-1 )
        end
    end
end

function print(val)
    reaper.ShowConsoleMsg(tostring(val).."\n")
end

hwnd = reaper.MIDIEditor_GetActive()
take = reaper.MIDIEditor_GetTake(hwnd)
time1 = reaper.time_precise()
--SoloChannel(2) -- 0.028 s
--SoloChannelOriSort(take,2) -- 7s
SoloChannelOri(take,2) -- 95s

print(reaper.time_precise()-time1)

the results in a MIDI with 15k MIDI notes are
1. SoloChannel 0.028s +-
2. SoloChannelSort 7s
3 SoloChannelNoSort 98s

[daniellumertz]

I wonder if there is a problem deleting all CC using this:

(because of CC that even Reaper don't let the user edit like CC123)

function DelCC(take, ch) 
    local retval, MIDIstring = reaper.MIDI_GetAllEvts(take, "") 
    local MIDIlen = MIDIstring:len()
    local tableEvents = {}
    local stringPos = 1
    --local pos=0 
    while stringPos < MIDIlen do 
        offset, flags, ms, stringPos = string.unpack("i4Bs4", MIDIstring, stringPos) -- Unpack the MIDI[stringPos] event 
        --pos=pos+offset -- For keeping track of the Postion of the notes in Ticks
        if ms:len() == 3 and ms:byte(1)>>4 == 11 then -- if ms:len == 3 means it have 3 messages(Notes, CC,Poly Aftertouch, Pitchbend )  (ms:byte(1)>>4 == 9 or ms:byte(1)>>4 == 8) note on or off
            ms=""
        end 
        table.insert(tableEvents, string.pack("i4Bs4", offset, flags, ms))
    end 
    reaper.MIDI_SetAllEvts(take, table.concat(tableEvents)) 
end

[juliansader]

Originally Posted by daniellumertz

I wonder if there is a problem deleting all CC using this:

(because of CC that even Reaper don't let the user edit like CC123)

Yes, there will be a problem. The loop should end before the final All-Notes-Off CC.

If REAPER doesn't find an A-N-O CC at the end of a take, it will automatically insert one, but the new A-N-O will likely be at a different position (directly after the last event), thereby changing the source length of your take.

[daniellumertz]

Ok I will make it quit the loop from MIDI CC 120 to match reaper preferences

[_Stevie_]

A little follow up here, do we actually need MIDIsort for SetAllEvts?

[daniellumertz]

In the function I made with Set All Events I haven't used MIDI Sort. So I don't think so (?)

[_Stevie_]

Great, that's what I hoped