[Ffmpeg-devel] Seg fault
Mon Nov 21 00:13:25 CET 2005
I am getting a segmentation fault in ByteSwap32 of bswap.h
All I did was exchange the diff_pixels_mmx routine with a new one and now I
get the segemntation fault in a totally unrelated area. On my test sequence it
occurs in the 7th frame, so all is okay for over 8,000 thousand blocks.
It occurs from put_bits being called from mpeg1_encode_block and occurs on
block number 5 of the macroblock.
It is either a subtle bug with ByteSwap32 or a compiler / linker problem. I
changed the optimisation level down to 1 and deleted the frame pointer removal
option but that didn't fix it. The new pixel_diff routine I am using is being
linked in from a Windows library but if there was some weird linker error I
doubt I would have managed to get through 8,000+ blocks before encountering a
problem that resulted from bad linkage.
The src of the ffmpeg code I crash in is:
static inline uint32_t ByteSwap32(uint32_t x)
#if __CPU__ > 386
"=r" (x) :
" rorl $16,%0\n"
" xchgb %b0,%h0":
LEGACY_REGS (x) :
I am using a P4 HT and gcc version 3.4.2 under MinGW.
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