R/soundscapes_spectro.R

In audioblast/audioBlastAnalyse: Analysis service for audioBlast!

#' Generate spectra for soundscapes in one minute chunks
#'
#' @param db database connector
#' @param source Source
#' @param id id (unique within source)
#' @param file url to file
#' @param type MIME type
#' @param duration audio duration
#' @param tmp Location to download temp file
#' @param force If TRUE recalculates all values
#' @param verbose If TRUE outputs debugging information
#' @param save.path Path to save data
#' @export
#' @importFrom seewave spec
#' @importFrom utils write.csv
soundscapes_spectro <- function(db, source, id, file, type, duration, tmp,
                                force=FALSE, verbose=FALSE, save.path=".") {
  n <- ceiling(duration/60)
  if (force==TRUE) {
    deleteAllAnalyses(db, source, id, justR=TRUE)
  }

  if (duration == 0) {
    if (verbose) print("Provided duration is zero -- skipping")
    return()
  }

  for (i in (1:n)) {
    duration <- av_media_info(tmp)$duration

    from <- (i-1)*60
    to <- i*60
    complete <- 1

    if (duration < 60 || (duration - (i-1)*60) < 60) {
      complete <- 0
    }

    if (!complete || i*60 == duration) {
        w <- readAudio(tmp, from=from, units="seconds")
    } else {
      av::av_audio_convert(tmp, output="temp.wav")
      w <- readWave("temp.wav")
    }

    if (is.logical(w)) return()

    if (verbose) print(paste("Spectro startTime:",(i-1)*60))
    s <- spec(w, wl=256, plot=FALSE)

    #Hack as seewave spec doesn't always work
    ss <- seq(from=0, to=w@samp.rate/2, along.with=s[,2])
    v <- cbind(ss, s[,2])

    path <- paste(save.path, source, id, sep="/")
    if (!dir.exists(path)) {
      dir.create(path, recursive=TRUE)
    }
    write.csv(v, paste(path, paste0((i-1)*60,".spec.csv"), sep="/"), quote=FALSE, row.names=FALSE,
              col.names=FALSE)
  }
}