R/00_tuneR_funs.R
In moodymudskipper/midi: Work with midi Objects
#
#
# # convert to bytes the length of a track chunk
# # var_length_raw(380) # 82 7c
# var_length_raw <- function(n) {
# bytes <- n %% 128
# n <- n %/% 128
# while (n != 0) {
# bytes <- c(n %% 128, bytes)
# n <- n %/% 128
# }
# # add a bit to the left except for last one
# n_bytes <- length(bytes)
# bytes[-n_bytes] <- bytes[-n_bytes] + 128
# as.raw(bytes)
# }
#
# # returns the var length AND the number of bytes that contains it
# readVarLength_bkp <- function(con){
# # in principle should be recursive, but using 4 bytes is enough for practical uses
# b <- numeric(4)
# b[1] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 1
# if(b[1] > 127){
# b[1] <- (b[1]-128) * 2^7
# b[2] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 2
# if(b[2] > 127){
# b[2] <- b[2]-128
# b <- b*2^7
# b[3] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 3
# if(b[3] > 127){
# b[3] <- b[3]-128
# b <- b*2^7
# b[4] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 4
# }
# }
# }
# c(sum(b), bytes)
# }
#
# readMTrkEvent <- function(con, lastEventChannel = NA){
# DTtemp <- readVarLength(con)
# DT <- DTtemp[1]
# n_DT_bytes <- DTtemp[2]
#
# EventChannel <- readBin(con, raw(0), n = 1)
# # the first character of the byte is the first 4 bits
# event <- substr(EventChannel, 1, 1)
# backseeked <- 0
#
# # if it's less than 8 it means that the byte is less than 128
# # which means "running status"
# # this means the current byte doesn't describe the channel, we'll use the last
# # one instead, and re-position the cursor.
#
# # see http://midi.teragonaudio.com/tech/midispec/run.htm
#
# # the connection is re-positioned before our last read, so we can read the channel
# # from there
#
# if(event < "8"){
# seek(con, where = -1, origin = "current")
# EventChannel <- lastEventChannel
# event <- substr(EventChannel, 1, 1)
# backseeked <- 1
# }
#
# # Channel Voice Messages
#
# # This is this table, transcribed in quartet :
# # http://www.music.mcgill.ca/~ich/classes/mumt306/StandardMIDIfileformat.html#BMA1_
# eventName <- switch(event,
# "8" = "Note Off",
# "9" = "Note On",
# "a" = "Note Aftertouch",
# "b" = "Controller",
# "c" = "Program Change",
# "d" = "Channel Aftertouch",
# "e" = "Pitch Bend",
# "f" = "Meta or System")
#
# # The extra quartet will give the channel number, and the following bytes will give the data
# # (parameters), these should be encoded adhoc
# # if think the logic can be changed here, it's been organized to avoid copy and paste, and
# # params are generalized, event should instead be a list of params with relevant names and no NA
# #
#
# # Meta-Event Definitions
#
# if(EventChannel == "ff"){
# # In a MIDI file this is used as an escape to introduce <meta events>.
# type <- as.character(readBin(con, raw(0), n = 1))
# # FIXME: We need a special case for each possible meta event. A data.frame is not the best possible solution...,
# # probably define separate S4 classes?
# elength <- readVarLength(con)
# eventName <- switch(type,
# "00" = "Sequence Number",
# "01" = "Text Event",
# "02" = "Copyright Notice",
# "03" = "Sequence/Track Name",
# "04" = "Instrument Name",
# "05" = "Lyric",
# "06" = "Marker",
# "07" = "Cue Point",
# "08" = "Program Name",
# "09" = "Device Name",
# "20" = "MIDI Channel Prefix",
# "21" = "MIDI Port",
# "2f" = "End of Track",
# "51" = "Set Tempo",
# "54" = "SMPTE Offset",
# "58" = "Time Signature",
# "59" = "Key Signature",
# "7f" = "Sequencer Specific",
# "Meta")
#
# if(type > "00" && type < "10")
# eventData <- readChar(con, elength[1])
# else
# eventData <- paste(as.character(switch(type,
# "00" = readBin(con, integer(0), n = 1, size = elength[1], endian = "big", signed = FALSE),
# "20" = readBin(con, integer(0), n = 1, size = elength[1], endian = "big", signed = FALSE),
# "21" = readBin(con, integer(0), n = 1, size = elength[1], endian = "big", signed = FALSE),
# "51" = as.vector(readBin(con, integer(0), n = 3, size = 1, endian = "big", signed = FALSE) %*% c(256^2, 256, 1)),
# "58" = {temp <- readBin(con, integer(0), n = 4, size = 1, endian = "big", signed = FALSE)
# paste0(temp[1], "/", 2^temp[2], ", ", temp[3], " clocks/tick, ", temp[4], " 1/32 notes / 24 clocks")
# },
# "59" = {sharpflat <- readBin(con, integer(0), n = 1, size = 1, endian = "big")
# majorminor <- readBin(con, integer(0), n = 1, size = 1, endian = "big")
# ma <- paste(c("B (H)", "Gb", "Db", "Ab", "Eb", "Bb", "F", "C", "G", "D", "A", "E", "B (H)", "F#", "C#"), "major")
# mi <- paste(c("Ab","Eb", "Bb", "F", "C", "G", "D", "A", "E", "B (H)", "F#","C#","G#","D#", "A#"), "minor")
# if(majorminor == 1) mi[sharpflat+8] else ma[sharpflat+8]
# },
# readBin(con, raw(0), n = elength[1])
# )), collapse=" x ")
#
# return(list(deltatime=DT, event=eventName, type=type, channel = NA, parameter1=NA, parameter2=NA,
# parameterMetaSystem=eventData, bytes=2+sum(elength)+n_DT_bytes-backseeked, EventChannel=EventChannel))
# }
# if(event == "f"){
# eventName <- "System"
# elength <- readVarLength(con)
# seek(con, where = elength[1], origin = "current")
# return(list(deltatime=DT, event=eventName, type=NA, channel = NA, parameter1=NA, parameter2=NA,
# parameterMetaSystem=NA, bytes=1+sum(elength)+n_DT_bytes-backseeked, EventChannel=EventChannel))
# }
# channel <- as.numeric(rawShift(EventChannel, 4)) / 2^4
# parameter1 <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# parameter2 <- if(event %in% c("c", "d")) NA else readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
#
#
# return(list(deltatime=DT, event=eventName, type=NA, channel = channel, parameter1=parameter1, parameter2=parameter2,
# parameterMetaSystem=NA, bytes=2+n_DT_bytes+ !(event %in% c("c", "d"))-backseeked, EventChannel=EventChannel))
# }
#
# readMidi <- function(file){
# con <- file(description = file, open = "rb")
# on.exit(close(con))
# MThd <- readChar(con, 4)
# if(MThd != "MThd")
# stop("No Header Chunk in this Midi (?)")
# MThd_length <- readBin(con, integer(0), n = 1, size = 4, endian = "big")
# if(MThd_length != 6)
# stop("Unexpected Header Chunk size")
# MThd_format <- readBin(con, integer(0), n = 1, size = 2, endian = "big", signed = FALSE)
# if(!(MThd_format %in% 0:2))
# stop("Unexpected Mide file format")
# MThd_tracks <- readBin(con, integer(0), n = 1, size = 2, endian = "big", signed = FALSE)
#
# # FIXME: MThd_division < 0 can appear in Midi files with a very different interpretation!
# MThd_division <- readBin(con, integer(0), n = 1, size = 2, signed = TRUE, endian = "big")
# if(MThd_division < 0){
# stop("Midi representation of timing: Frames per second / ticks per frame not yet implemented, please ask the author")
# }
#
# allTracks <- list()
# for(track in 1:MThd_tracks){
# MTrk <- readChar(con, 4)
# if(MTrk != "MTrk")
# stop("No Track Chunk in this Midi")
# MTrk_length <- readBin(con, integer(0), n = 1, size = 4, endian = "big")
# MeventList <- list()
# bytes <- 0
# i <- 0
# while(bytes < MTrk_length){
# i <- i+1
# MeventList[[i]] <- readMTrkEvent(con, if(i>1) MeventList[[i-1]][["EventChannel"]] else NA)
# bytes <- bytes + MeventList[[i]][["bytes"]]
# }
# if( MeventList[[i]][["type"]] != "2f")
# stop("No end of track event after track length bytes")
# thisTrack <- do.call("rbind", lapply(MeventList, function(x) as.data.frame(x, stringsAsFactors=FALSE)))
# thisTrack <- thisTrack[,-(ncol(thisTrack)-(0:1))] # remove bytes and EventChannel information
# thisTrack[,1] <- cumsum(thisTrack[,1])
# names(thisTrack)[1] <- "time"
# thisTrack$track <- track
# allTracks[[track]] <- thisTrack
# }
# allTracks <- do.call("rbind", allTracks)
# allTracks$event[allTracks$event == "Note On" & allTracks$parameter2 == 0] <- "Note Off"
# allTracks$event <- factor(allTracks$event,
# levels = c("Note Off", "Note On", "Note Aftertouch", "Controller", "Program Change", "Channel Aftertouch",
# "Pitch Bend", "Meta", "System", "Sequence Number", "Text Event", "Copyright Notice",
# "Sequence/Track Name", "Instrument Name", "Lyric", "Marker", "Cue Point", "Program Name",
# "Device Name", "MIDI Channel Prefix", "MIDI Port",
# "End of Track", "Set Tempo", "SMPTE Offset", "Time Signature", "Key Signature", "Sequencer Specific"))
# allTracks
# }
moodymudskipper/midi documentation built on July 16, 2020, 1:54 a.m.
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#
#
# # convert to bytes the length of a track chunk
# # var_length_raw(380) # 82 7c
# var_length_raw <- function(n) {
# bytes <- n %% 128
# n <- n %/% 128
# while (n != 0) {
# bytes <- c(n %% 128, bytes)
# n <- n %/% 128
# }
# # add a bit to the left except for last one
# n_bytes <- length(bytes)
# bytes[-n_bytes] <- bytes[-n_bytes] + 128
# as.raw(bytes)
# }
#
# # returns the var length AND the number of bytes that contains it
# readVarLength_bkp <- function(con){
# # in principle should be recursive, but using 4 bytes is enough for practical uses
# b <- numeric(4)
# b[1] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 1
# if(b[1] > 127){
# b[1] <- (b[1]-128) * 2^7
# b[2] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 2
# if(b[2] > 127){
# b[2] <- b[2]-128
# b <- b*2^7
# b[3] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 3
# if(b[3] > 127){
# b[3] <- b[3]-128
# b <- b*2^7
# b[4] <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# bytes <- 4
# }
# }
# }
# c(sum(b), bytes)
# }
#
# readMTrkEvent <- function(con, lastEventChannel = NA){
# DTtemp <- readVarLength(con)
# DT <- DTtemp[1]
# n_DT_bytes <- DTtemp[2]
#
# EventChannel <- readBin(con, raw(0), n = 1)
# # the first character of the byte is the first 4 bits
# event <- substr(EventChannel, 1, 1)
# backseeked <- 0
#
# # if it's less than 8 it means that the byte is less than 128
# # which means "running status"
# # this means the current byte doesn't describe the channel, we'll use the last
# # one instead, and re-position the cursor.
#
# # see http://midi.teragonaudio.com/tech/midispec/run.htm
#
# # the connection is re-positioned before our last read, so we can read the channel
# # from there
#
# if(event < "8"){
# seek(con, where = -1, origin = "current")
# EventChannel <- lastEventChannel
# event <- substr(EventChannel, 1, 1)
# backseeked <- 1
# }
#
# # Channel Voice Messages
#
# # This is this table, transcribed in quartet :
# # http://www.music.mcgill.ca/~ich/classes/mumt306/StandardMIDIfileformat.html#BMA1_
# eventName <- switch(event,
# "8" = "Note Off",
# "9" = "Note On",
# "a" = "Note Aftertouch",
# "b" = "Controller",
# "c" = "Program Change",
# "d" = "Channel Aftertouch",
# "e" = "Pitch Bend",
# "f" = "Meta or System")
#
# # The extra quartet will give the channel number, and the following bytes will give the data
# # (parameters), these should be encoded adhoc
# # if think the logic can be changed here, it's been organized to avoid copy and paste, and
# # params are generalized, event should instead be a list of params with relevant names and no NA
# #
#
# # Meta-Event Definitions
#
# if(EventChannel == "ff"){
# # In a MIDI file this is used as an escape to introduce <meta events>.
# type <- as.character(readBin(con, raw(0), n = 1))
# # FIXME: We need a special case for each possible meta event. A data.frame is not the best possible solution...,
# # probably define separate S4 classes?
# elength <- readVarLength(con)
# eventName <- switch(type,
# "00" = "Sequence Number",
# "01" = "Text Event",
# "02" = "Copyright Notice",
# "03" = "Sequence/Track Name",
# "04" = "Instrument Name",
# "05" = "Lyric",
# "06" = "Marker",
# "07" = "Cue Point",
# "08" = "Program Name",
# "09" = "Device Name",
# "20" = "MIDI Channel Prefix",
# "21" = "MIDI Port",
# "2f" = "End of Track",
# "51" = "Set Tempo",
# "54" = "SMPTE Offset",
# "58" = "Time Signature",
# "59" = "Key Signature",
# "7f" = "Sequencer Specific",
# "Meta")
#
# if(type > "00" && type < "10")
# eventData <- readChar(con, elength[1])
# else
# eventData <- paste(as.character(switch(type,
# "00" = readBin(con, integer(0), n = 1, size = elength[1], endian = "big", signed = FALSE),
# "20" = readBin(con, integer(0), n = 1, size = elength[1], endian = "big", signed = FALSE),
# "21" = readBin(con, integer(0), n = 1, size = elength[1], endian = "big", signed = FALSE),
# "51" = as.vector(readBin(con, integer(0), n = 3, size = 1, endian = "big", signed = FALSE) %*% c(256^2, 256, 1)),
# "58" = {temp <- readBin(con, integer(0), n = 4, size = 1, endian = "big", signed = FALSE)
# paste0(temp[1], "/", 2^temp[2], ", ", temp[3], " clocks/tick, ", temp[4], " 1/32 notes / 24 clocks")
# },
# "59" = {sharpflat <- readBin(con, integer(0), n = 1, size = 1, endian = "big")
# majorminor <- readBin(con, integer(0), n = 1, size = 1, endian = "big")
# ma <- paste(c("B (H)", "Gb", "Db", "Ab", "Eb", "Bb", "F", "C", "G", "D", "A", "E", "B (H)", "F#", "C#"), "major")
# mi <- paste(c("Ab","Eb", "Bb", "F", "C", "G", "D", "A", "E", "B (H)", "F#","C#","G#","D#", "A#"), "minor")
# if(majorminor == 1) mi[sharpflat+8] else ma[sharpflat+8]
# },
# readBin(con, raw(0), n = elength[1])
# )), collapse=" x ")
#
# return(list(deltatime=DT, event=eventName, type=type, channel = NA, parameter1=NA, parameter2=NA,
# parameterMetaSystem=eventData, bytes=2+sum(elength)+n_DT_bytes-backseeked, EventChannel=EventChannel))
# }
# if(event == "f"){
# eventName <- "System"
# elength <- readVarLength(con)
# seek(con, where = elength[1], origin = "current")
# return(list(deltatime=DT, event=eventName, type=NA, channel = NA, parameter1=NA, parameter2=NA,
# parameterMetaSystem=NA, bytes=1+sum(elength)+n_DT_bytes-backseeked, EventChannel=EventChannel))
# }
# channel <- as.numeric(rawShift(EventChannel, 4)) / 2^4
# parameter1 <- readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
# parameter2 <- if(event %in% c("c", "d")) NA else readBin(con, integer(0), n = 1, size = 1, signed = FALSE, endian = "big")
#
#
# return(list(deltatime=DT, event=eventName, type=NA, channel = channel, parameter1=parameter1, parameter2=parameter2,
# parameterMetaSystem=NA, bytes=2+n_DT_bytes+ !(event %in% c("c", "d"))-backseeked, EventChannel=EventChannel))
# }
#
# readMidi <- function(file){
# con <- file(description = file, open = "rb")
# on.exit(close(con))
# MThd <- readChar(con, 4)
# if(MThd != "MThd")
# stop("No Header Chunk in this Midi (?)")
# MThd_length <- readBin(con, integer(0), n = 1, size = 4, endian = "big")
# if(MThd_length != 6)
# stop("Unexpected Header Chunk size")
# MThd_format <- readBin(con, integer(0), n = 1, size = 2, endian = "big", signed = FALSE)
# if(!(MThd_format %in% 0:2))
# stop("Unexpected Mide file format")
# MThd_tracks <- readBin(con, integer(0), n = 1, size = 2, endian = "big", signed = FALSE)
#
# # FIXME: MThd_division < 0 can appear in Midi files with a very different interpretation!
# MThd_division <- readBin(con, integer(0), n = 1, size = 2, signed = TRUE, endian = "big")
# if(MThd_division < 0){
# stop("Midi representation of timing: Frames per second / ticks per frame not yet implemented, please ask the author")
# }
#
# allTracks <- list()
# for(track in 1:MThd_tracks){
# MTrk <- readChar(con, 4)
# if(MTrk != "MTrk")
# stop("No Track Chunk in this Midi")
# MTrk_length <- readBin(con, integer(0), n = 1, size = 4, endian = "big")
# MeventList <- list()
# bytes <- 0
# i <- 0
# while(bytes < MTrk_length){
# i <- i+1
# MeventList[[i]] <- readMTrkEvent(con, if(i>1) MeventList[[i-1]][["EventChannel"]] else NA)
# bytes <- bytes + MeventList[[i]][["bytes"]]
# }
# if( MeventList[[i]][["type"]] != "2f")
# stop("No end of track event after track length bytes")
# thisTrack <- do.call("rbind", lapply(MeventList, function(x) as.data.frame(x, stringsAsFactors=FALSE)))
# thisTrack <- thisTrack[,-(ncol(thisTrack)-(0:1))] # remove bytes and EventChannel information
# thisTrack[,1] <- cumsum(thisTrack[,1])
# names(thisTrack)[1] <- "time"
# thisTrack$track <- track
# allTracks[[track]] <- thisTrack
# }
# allTracks <- do.call("rbind", allTracks)
# allTracks$event[allTracks$event == "Note On" & allTracks$parameter2 == 0] <- "Note Off"
# allTracks$event <- factor(allTracks$event,
# levels = c("Note Off", "Note On", "Note Aftertouch", "Controller", "Program Change", "Channel Aftertouch",
# "Pitch Bend", "Meta", "System", "Sequence Number", "Text Event", "Copyright Notice",
# "Sequence/Track Name", "Instrument Name", "Lyric", "Marker", "Cue Point", "Program Name",
# "Device Name", "MIDI Channel Prefix", "MIDI Port",
# "End of Track", "Set Tempo", "SMPTE Offset", "Time Signature", "Key Signature", "Sequencer Specific"))
# allTracks
# }
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