Hi, In the encoder, there are two arrays in the function FrameCodeB() These need aligning or the sse2 crashes was (line 1929, or there abouts) int16_t dct_codes[6 * 64]; int16_t qcoeff[6 * 64]; needs changing to DECLARE_ALIGNED_MATRIX(dct_codes, 6, 64, int16_t, CACHE_LINE); DECLARE_ALIGNED_MATRIX(qcoeff, 6, 64, int16_t, CACHE_LINE); will provide working sse2 again Jim