小练习一则:将.srt格式的视频字幕文件中字幕向前或向后推移一段时间

.srt字幕格式如下：

1
00:00:48,860 --> 00:00:51,400
站好，你不喜欢你的工作吗？

2
00:01:00,160 --> 00:01:01,540
食物

3
00:01:06,090 --> 00:01:08,090
你要去哪里？

.......

ruby代码如下：

ruby 代码

# param: time_str : string with "00:01:08,123" like format
# param: offset : int, seconds to shift ahead
def offset(time_str, offset)
  new_time = Time.parse(time_str) - offset
  format("%02d:%02d:%02d,%03d", new_time.hour, new_time.min, new_time.sec, new_time.usec/1000)
end

def convert(src_file_path, dst_file_path, offset)
  open(dst_file_path, "w") do |dst_file|
    open(src_file_path, "r").each_line do |line|
      if line.include?(" --> ")
        new_line = line.split(" --> ").collect{ |time_str| offset(time_str, offset)}.join(" --> ")
        dst_file.puts new_line
        puts "line #{line} converted to #{new_line}"
      else
        dst_file.puts line
      end
    end
  end
end

convert "c:\\src.srt", "c:\\dst.srt", 90