Adjust timestamps in an SRT file

adjust-srt.rb

adjust_by = 48 # seconds
srt = File.read(File.expand_path("~/Downloads/EN.srt"))

new_srt = srt.
  split("\r\n\r\n").
  map {|s| s.split("\r\n")}.
  map do |i, times, *values|
    
    new_times = times.split(" --> ").map {|t| (Time.strptime(t, "%H:%M:%S,%L") + adjust_by).strftime("%H:%M:%S,%L")}.join(" --> ")

    [i, new_times, values.join("\r\n")].join("\r\n")
  end.join("\r\n\r\n")

File.write(File.expand_path("~/Downloads/EN-adjusted.srt"), new_srt)