DirectVobSub sometimes not working [solved]

[Eric B]

I've ripped some DVDs and like to have the subtitles for watching movie on my PC. I do not want to spend the effort of OCR/SRT, thus using vobsub (tool from MeGUI).
I used to use vobsub and directvobsub for years. I am not encountering pb with the playback. I am using the old TCMP v4 or the latest MPC-HD as video player, updated directvobsub to v2.39 and still using the good old vobsub 2.23. Within both players, sometimes, the subtitles are properly displayed (either located nearby the mkv, or muxed within), sometimes, they are not displayed at all. I have no idea why. All the latest sub extracted are particularly not working. I've tried the file only (same name as video), the mux in mp4 and the mux in mkv. No change in behavior.
The sub files are there with the idx and weighting some 30MB+, so they seems to be ok.
I've tried to play arround with the settings of directvobsub, but I do not get anything better.
Any idea?

[Eric B]

I've solved the pb in a unexpected way: I am using cyberlink powerdvd7 as AVC decoder. I've updated it and now it works all fine with subtitles.
I've spend many time on understanding why some subtitle where not on sync, and the answer is simple: subtitle were not ripped on the correct angle: instead of using megui tool, I've reused vobsub configure and could choose the angle. Now the subtitle are sync all movie long.