Use memcpy() instead of a for loop in mdct512().

8% faster in function. Originally committed as revision 26027 to svn://svn.ffmpeg.org/ffmpeg/trunk
14 years ago · 9d8533368f
parent b6f6204db9
commit 9d8533368f
1 changed files with 1 additions and 2 deletions
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@ -339,8 +339,7 @@ static void mdct512(int32_t *out, int16_t *in)
    /* shift to simplify computations */
    for (i = 0; i < MDCT_SAMPLES/4; i++)
        rot[i] = -in[i + 3*MDCT_SAMPLES/4];
-    for (;i < MDCT_SAMPLES; i++)
-        rot[i] =  in[i -   MDCT_SAMPLES/4];
+    memcpy(&rot[MDCT_SAMPLES/4], &in[0], 3*MDCT_SAMPLES/4*sizeof(*in));

    /* pre rotation */
    for (i = 0; i < MDCT_SAMPLES/4; i++) {