Fix subtitles in srt format

Small helper script to add time offset to entire entries in subtitle file:

 import sys  
 assert(len(sys.argv[1]) > 3)  
 fin  = open(sys.argv[1], 'r')  
 fout = open(sys.argv[2], 'w')  
 delta = int(sys.argv[3])  
 def updClock(m, s):  
   while s >= 60:  
     s -= 60  
     m += 1  
   while s < 0:  
     s += 60   
     m -= 1  
   return m,s    
 def adddelta(time, dt):  
   # 00:00:37,149  
   h,m,s_ms = time.split(':')  
   s,ms = s_ms.split(',')  
   m,s = updClock(int(m), int(s) + dt)  
   h,m = updClock(int(h), int(m))  
   return '%d:%d:%d,%s'%(h,m,s,ms)     
 for line in fin.readlines():  
   # 00:00:37,149 --> 00:00:39,083  
   parts = line.split(' --> ')  
   if len(parts) <= 1:  
     fout.write(line)  
     continue  
   fout.write(adddelta(parts[0], delta) + ' --> ' + adddelta(parts[1], delta))  
 fout.close()  

Usage: python