Python對srt的解析

最過在看Desperate_Housewives_-_Season_1，奇藝上只有中文字幕，對於我等希望練習英語聽力的人來講是一大缺憾。網上遍尋不到合適的工具來顯示外掛字幕。正好最近在學習Python，於是心想求人不如求已，自已動手做一個得了。

凡事得有步驟，我的構想如下：
1. 分析SRT格式檔案；
2. 提取時間資訊和要顯示的字元，此為最重要的部分，最好的方式是調用Python的Regex來提取相關的資訊；
3. 調用pyosd顯示，類似於QQ音樂播放器的歌詞顯示功能；

關於SRT的說明，可以參考http://en.wikipedia.org/wiki/SubRip。不過因為工作中經常接觸外掛字幕，所以對於SRT也有一定的瞭解.
The SubRip file format is "perhaps the most basic of all subtitle formats."[10] SubRip files are named with the extension .srt, and contain formatted plain text. The time format used is hours:minutes:seconds,milliseconds. The decimal separator used is the comma, since the program was written in France. The line break used is often the CR+LF pair. Subtitles are numbered sequentially, starting at 1.

    Subtitle number　　　　　　　　　　//相當於index,標記subtitle的序號
    Start time --> End time　　　　　　  //開始與結束時間，duration可以據此計算出來　　
    Text of subtitle (one or more lines)     //字幕資訊
    Blank line[11][10] 　　　　　　　　  //空白行

以下是實現的代碼，很rough, 我還在修改中，只是實現了部分功能：

import reimport pyosdimport sysimport getoptimport timeclass srtParsing():    index = 0    #hour minute sec = 0    duration = 0    print time.time()        def srtGetIndex(self, line):reg = re.compile('\d')if(reg.search(line)):    print line    def srtGetTimeStamp(self, line):reg = re.compile('\-\-\>')p = pyosd.osd()if(reg.search(line)):    print line    time = line.split('-->')    #START TIME:    hour_end = time[1].split(':')    minute_end = int(hour_end[1])    sec_end = hour_end[2].split(',')    hour_end = int(hour_end[0])    mis_end = int(sec_end[1])    sec_end = int(sec_end[0])    print "end-->h:%d m:%d s:%d,mis:%d" %(hour_end, minute_end, sec_end, mis_end)    #END TIME:    hour_start = time[0].split(':')    minute_start = int(hour_start[1])    sec_start = hour_start[2].split(',')    hour_start = int(hour_start[0])    mis_start = sec_start[1]    sec_start = int(sec_start[0])    time_start = hour_start * 60 * 60 + minute_start * 60 + sec_start    print "start time :%d" %time_start    time_end = hour_end * 60 * 60 + minute_end * 60 + sec_end    print "end time:%d" %time_end    duration = time_end - time_start    print duration    p.set_timeout(duration)    def srtGetSubInfo(self, line):reg = re.compile(r'^[a-zA-Z]')p = pyosd.osd()p.set_pos(pyosd.POS_BOT)p.set_colour("YELLOW")p.set_align(1)#p.set_shadow_offset(10)p.set_vertical_offset(100)if(reg.search(line)):    print line    p.display(line)    p.wait_until_no_display()if __name__ == "__main__":    srt = srtParsing()    f=open("/home/workspace/subtitle/src/dh.srt")    for line in f:        srt.srtGetTimeStamp(line)        srt.srtGetSubInfo(line)

　　下一步工作是對時間的控制，需要從系統中擷取時間與標籤對比，從而精確控制顯示.