LWLibavSource don't output frames in correct time order

[MonoS]

since a couple of months i'm encountering a bug into lsmash using vapoursynth for m2ts and m2ts muxed in mkv, i tried a lot to reproduce this issues but is impossible, it's random AFAIK.

It happens using lsmash and mdegrain [tried with tr=2] together [only lsmash or using another source filter don't seems to cause the problem] and consist of wrong decoding sequences or duplicated frames [for example ABDCE... or ABBDE...].

I've tried setting threads to 1 thinking it was a race condition but without success.

As i stated, i cannot offer a raw sample because it's random and usually appear on the middle of the encode [even cutting the precise scene in which this happens i was unable to reproduce this].

This is the most i can give you http://www.mediafire.com/watch/2mg9wec9616kvjj/test_lsmash.mkv