sourceフォルダに48kHzのwavファイルを放り込むとdestにラウドネスノーマライズされて出てくるやつ（ITU−R BS1770,1771準拠）/ Loudness normalize 48kHz wav files from 'source' into 'dest'(based on ITU−R BS1770,1771)

norm_loudness.R

library(tuneR)

library(signal)

if(!is.na(commandArgs(T)[1])){
  isPrenormalize = commandArgs(T)[1] == "-normalize"
}else{
  isPrenormalize=FALSE
}

print(paste("Pre-normalize: " ,isPrenormalize))

prefilter1 <- Arma(c(1.53512485958697,-2.69169618940638,1.19839281085285),c(1,-1.69065929318241,0.73248077421585))

prefilter2 <- Arma(c(1.0,-2.0,1.0),c(1,-1.99004745483398,0.99007225036621))

meansq <- function(array){
  return(mean(array^2))
}

apply_kfilter <- function(array){
  applied <- filter(prefilter1,array)
  applied <- filter(prefilter2,applied)
  return(applied)
}


measureloudness <- function(filename ,prenormalize=TRUE){
  print(paste("measuring loudness of ",filename,"..."))
  src_path <- paste('source/',filename,sep = "")
  wavobj <- readWave(src_path)
  print(wavobj)
  if(wavobj@samp.rate!=48000){
    print("SR isn't 48000.")
    return(FALSE);
  }
  norm <- normalize(wavobj,unit = "1",pcm = FALSE,rescale = prenormalize)
  left <- norm@left
  left<- apply_kfilter(left)
  meansq_left <-meansq(left)
  if(wavobj@stereo){
    right <- norm@right
    right <- apply_kfilter(right)
    meansq_right <-meansq(right)
    loudness <- meansq_left+meansq_right
  }else{
    loudness <- meansq_left
  }

  lkfs <- -0.691 + 10*log(loudness,10)
  print(paste(lkfs,"LKFS"))
  return(lkfs)

}



dbtoa <- function(db){
  return(10^(db/20))
}
applygain <- function(filename,loudness,min_loudness,prenormalize=TRUE){
  print(paste("normalizing " , filename,"..."))
  g_difference <- loudness- min_loudness
  print(paste("gain diffrence : " , g_difference))
  src_path <- paste('source/',filename,sep = "")
  wavobj <- readWave(src_path)
  # print(wavobj)
  norm <-  normalize(wavobj,unit = "1",pcm = FALSE,rescale = prenormalize)
  g <- dbtoa(-g_difference)
  print(paste("gain coefficient is ",g))
  newleft <- as.integer(norm@left * g * (2^23-1))
  if(norm@stereo){
  newright<- as.integer(norm@right * g * (2^23-1))
  newwav <- Wave(left =newleft,right=newright,samp.rate = 48000,bit = 24,pcm = TRUE)
  writeWave(newwav,paste("dest/",filename,sep = ""))
  print(paste("wrote ",filename,"."))
}else{
  newwav <- Wave(left =newleft,samp.rate = 48000,bit = 24,pcm = TRUE)
  writeWave(newwav,paste("dest/",filename,sep = ""))
  print(paste("wrote ",filename,"."))
}
}
# start

files <- list.files('source','*.wav')

lkfsarray <- c()

for (f in files){
 lkfs <- measureloudness(f,isPrenormalize)
 lkfsarray <-c(lkfsarray,lkfs)
}

frame <- data.frame(FILE = files,LOUDNESS= lkfsarray)
print(frame)
minlkfs <- min(lkfsarray)
print(paste("minimum loudness is ",minlkfs,"LKFS"))

for(i in 1: length(files)){
  applygain(frame$FILE[i],frame$LOUDNESS[i],minlkfs,isPrenormalize)
}
print("end all sequence")