spumux gives brocken subs

I've used spumux to add .str subs into dvd file...

But in the result file some subs are brocken:

http://lj.shaplov.ru/2010/brocken_subs1.png
http://lj.shaplov.ru/2010/brocken_subs1.txt

http://lj.shaplov.ru/2010/brocken_subs2.png
http://lj.shaplov.ru/2010/brocken_subs2.txt

http://lj.shaplov.ru/2010/brocken_subs3.png
http://lj.shaplov.ru/2010/brocken_subs3.txt

$ ffmpeg -i src.vob

Seems stream 0 codec frame rate differs from container frame rate:
50.00 (50/1) -> 25.00 (25/1) Input #0, mpeg, from 'blond_step1.vob':
  Duration: 01:25:55.96, start: 0.500000, bitrate: 5424 kb/s

Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 16:15 DAR
4:3], 8500 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc 
Stream #0.1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s 
Stream #0.2[0x81]: Audio: ac3, 48000 Hz, stereo, s16, 448 kb/s 

$ cat subs-fr.xml
<subpictures>
  <stream>
   <textsub
filename="srt-fr.srt"
fontsize="28.0" font="arial.ttf" left-margin="0" right-margin="0"
             force="yes" movie-fps="25" subtitle-fps="25"
             movie-width="720" movie-height="576"
             horizontal-alignment="center"
   />
   </stream>
</subpictures>

$ spumux -s0 -m dvd subs-fr.xml <src.vob >dst.vob
Does not report any error.


Are there any way to solve this problem? Where to look for it?

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