r - 如何在无声的地方分割音频文件

Question

如下代码可以拆分wav.file，但设置剪切音频文件的持续时间有一个限制。请问R中是否有任何解决方案可以在无声的地方分割音频文件？

 library(seewave)
 #your audio file (using example file from seewave package)
 data(tico)
 audio <- tico
 #the frequency of your audio file
 freq <- 22050
  # the length and duration of your audio file
 totlen <- length(audio)
 totsec <- totlen/freq

  # the duration that you want to chop the file into
  seglen <- 0.5

  # defining the break points
  breaks <- unique(c(seq(0, totsec, seglen), totsec))
  index <- 1:(length(breaks)-1)
  # a list of all the segments
  lapply(index, function(i) audio[(breaks[i]*freq):(breaks[i+1]*freq)])
  # the above final line is the only difference between this code and the 
   # code provided by @Jean V. Adams

Answer 1

seewave包包含timer函数，该函数可检测静音和信号在哪里。需要一些注意才能使阈值，平滑度和最小持续时间正确，但这是一个示例。

    library(seewave)
    # make some example data
    sine <- synth(cf=1000, f = 22050, d = 2, output = 'Wave')
    sinewithsilence <- addsilw(wave = sine, at = 'middle', output = 'Wave', d = 0.5)
    testsignal1 <- pastew(sinewithsilence, sinewithsilence, output = 'Wave')
    testsignal2 <- addsilw(wave = testsignal1, at = 'end', output = 'Wave', d = 0.5)

    # choose one wav to split - uncomment as necessary
    #signal <- tico
    #signal <- testsignal1
    signal <- testsignal2
    totsec <- length(signal@left)/signal@samp.rate
    periods <- timer(signal, plot = T, threshold = 1, msmooth = c(100,0), dmin=0.1)

    starts <- periods$s.start
    ends <- periods$s.end
    if (length(starts) > length(ends)) {
        ends <- c(ends, totsec)
    }
    periods.df <- data.frame(starts, ends)

    splits = lapply(1:nrow(periods.df), function(i) cutw(signal, from = periods.df$starts[i], to = periods.df$ends[i], output = 'Wave'))

> str(splits)
List of 3
 $ :Formal class 'Wave' [package "tuneR"] with 6 slots
  .. ..@ left     : num [1:22132] 0 0.281 0.54 0.754 0.909 ...
  .. ..@ right    : num(0) 
  .. ..@ stereo   : logi FALSE
  .. ..@ samp.rate: num 22050
  .. ..@ bit      : num 16
  .. ..@ pcm      : logi TRUE
 $ :Formal class 'Wave' [package "tuneR"] with 6 slots
  .. ..@ left     : num [1:44265] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..@ right    : num(0) 
  .. ..@ stereo   : logi FALSE
  .. ..@ samp.rate: num 22050
  .. ..@ bit      : num 16
  .. ..@ pcm      : logi TRUE
 $ :Formal class 'Wave' [package "tuneR"] with 6 slots
  .. ..@ left     : num [1:22133] -0.997 -0.979 -0.883 -0.715 -0.49 ...
  .. ..@ right    : num(0) 
  .. ..@ stereo   : logi FALSE
  .. ..@ samp.rate: num 22050
  .. ..@ bit      : num 16
  .. ..@ pcm      : logi TRUE