Hi, The recent svn version of h264 added ff_h264_idct8_add_sse2, but the mb field of H264Context is still 8-byte aligned. +DECLARE_ALIGNED_16(DCTELEM, mb[16*24]); -DECLARE_ALIGNED_8(DCTELEM, mb[16*24]); will make it happy on SSE2 CPUs. -- netex at 163.com