i have a MPEG2 file and i am trying to convert it with x264 but in first pass it always crashes between encoding 20-21 minute of video. my original file is 720*576@25 fps. however when i resize video to any other size say 720*480@25 fps while keeping the other settings same, it converts video succesfully but i don't wanna resize my video . My System is Athlon 64 3200+, WinXP SP3, and using MediaCoder to convert my files . following is the excerpt of crash dump.

        00bf2479 4c               dec     esp
        00bf247a 2418             and     al,0x18
        00bf247c 8b54241c         mov     edx,[esp+0x1c]
        00bf2480 8b5c2420         mov     ebx,[esp+0x20]
        00bf2484 8b742424         mov     esi,[esp+0x24]
        00bf2488 8b7c2428         mov     edi,[esp+0x28]
        00bf248c 29d6             sub     esi,edx
        00bf248e 8d2c1e           lea     ebp,[esi+ebx]
        00bf2491 0f6f02           movq    mm0,qword ptr [edx]
        00bf2494 0f6f0c1a         movq    mm1,qword ptr [edx+ebx]
FAULT ->00bf2498 0fe00432 pavgb mm0,qword ptr [edx+esi] ds:0023:03675103=????????????????
        00bf249c 0fe00c2a         pavgb   mm1,qword ptr [edx+ebp]
        00bf24a0 0f7f00           movq    qword ptr [eax],mm0
        00bf24a3 0f7f0c08         movq    qword ptr [eax+ecx],mm1
        00bf24a7 83ef02           sub     edi,0x2
        00bf24aa 8d145a           lea     edx,[edx+ebx*2]
        00bf24ad 8d0448           lea     eax,[eax+ecx*2]
        00bf24b0 7fdf             jg      mencoder+0x7f2491 (00bf2491)
        00bf24b2 5d               pop     ebp
        00bf24b3 5f               pop     edi
        00bf24b4 5e               pop     esi
AFAIK the crashing instruction is one of the MMX instruction.

Any help appreciated.