This avoids a crash when the next slice is not a start slice and thus
pkt->data is still NULL.
This probably only happens with broken or unsupported files like
http://samples.mplayerhq.hu/real/multirate/JustaSpa1937_64kb.rm
that need further fixes, but keeping vst state consistent is still a good idea.
Originally committed as revision 19830 to svn://svn.ffmpeg.org/ffmpeg/trunk
pkt->size = vst->videobufpos + 8*(vst->cur_slice - vst->slices);
pkt->pts = AV_NOPTS_VALUE;
pkt->pos = vst->pktpos;
+ vst->slices = 0;
return 0;
}