srt Subtitle file time move

srt_time_move.lua

#!/usr/bin/lua

local MOVEMS = 1500

local line = io.read('*l')
while line do
  --local m = {string.match(line, '^([0-9][0-9]):([0-9][0-9]):([0-9][0-9]),([0-9]+) %-%-> ([0-9][0-9]):([0-9][0-9]):([0-9][0-9]),([0-9]+)$')}
  local mat = {string.match(line, "^(%d%d):(%d%d):(%d%d),(%d+) %-%-> (%d%d):(%d%d):(%d%d),(%d+)\r$")}
  if mat[1] then
    local d = {}
    local h, m, s, ms
    h = tonumber(mat[1])
    m = tonumber(mat[2])
    s = tonumber(mat[3])
    ms = tonumber(mat[4])

    ms = ms + MOVEMS

    while ms >= 1000 do
      ms = ms - 1000
      s = s + 1
    end
    while s >= 60 do
      s = s - 60
      m = m + 1
    end
    while m >= 60 do
      m = m - 60
      h = h + 1
    end

    table.insert(d, string.format('%02d:%02d:%02d,%d', h, m, s, ms))

    table.insert(d, ' --> ')

    h = tonumber(mat[5])
    m = tonumber(mat[6])
    s = tonumber(mat[7])
    ms = tonumber(mat[8])

    ms = ms + MOVEMS

    while ms >= 1000 do
      ms = ms - 1000
      s = s + 1
    end
    while s >= 60 do
      s = s - 60
      m = m + 1
    end
    while m >= 60 do
      m = m - 60
      h = h + 1
    end

    table.insert(d, string.format('%02d:%02d:%02d,%d', h, m, s, ms))

    table.insert(d, "\r")

    print(table.concat(d, ''))
  else
    print(line)
  end
  line = io.read('*l')
end