I've been converting my TV show DVDs into mkvs. Most of these DVDs have closed captions but no subtitles so I've been using CCExtractor to extract the captions to srt files. I want to play these on a WD TV Live Plus through an HDMI cable which is why I'm converting to srt since CC doesn't work through HDMI. TV show DVDs contain many episodes but the episodes don't match up to separate vobs for each episode. When you input multiple vobs in CCExtractor you end up with one long srt file containing the captions for all the episodes instead of an srt for each episode. I use PgcDemux to demux the video stream only (which contains the captions) for each episode and then input the demuxed video into CCExtractor which gives me individual srt files for each episode. This works well for getting the individual episode subs.

When I play the mkv files the subs are in sync for a while but gradually become out of sync so that by the end of each episode the subs are ahead of the audio by a couple of seconds. This happens when viewing on my pc or through WD TV Live Plus without fast forwarding or scrubbing (I watch it straight through.) If I watch the actual DVDs with a DVD player with CC enabled on my TV the captions stay in sync.

Why are these subs getting out of sync when the captions are in perfect sync? These are retail NTSC DVDs and not PAL/NTSC conversions. To correct this I've been opening the srt in Notepad and cutting the beginning text up to the point where it goes out of sync. I save the srt and use SrtTimeShifter to add time to the remaining text and then paste back the text I cut out and save the srt and repeat if necessary. Is there an easier way to correct this?

Thanks