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authorRoman Shaposhnik <roman@shaposhnik.org>2003-10-25 00:32:54 +0000
committerRoman Shaposhnik <roman@shaposhnik.org>2003-10-25 00:32:54 +0000
commit48b1f80012102847fb961c8d3dfb846b5665681c (patch)
treef38f606cb0aa9f296051cd0487daed4f63e99231 /libavcodec/jfdctfst.c
parentb292469633752def3d03341edd956ffd542b777e (diff)
downloadffmpeg-48b1f80012102847fb961c8d3dfb846b5665681c.tar.gz
* adding integer/floating point AAN implementations for DCT 2-4-8
Originally committed as revision 2430 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/jfdctfst.c')
-rw-r--r--libavcodec/jfdctfst.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/libavcodec/jfdctfst.c b/libavcodec/jfdctfst.c
index 899768d361..acaf284cd2 100644
--- a/libavcodec/jfdctfst.c
+++ b/libavcodec/jfdctfst.c
@@ -228,6 +228,113 @@ fdct_ifast (DCTELEM * data)
}
}
+/*
+ * Perform the forward 2-4-8 DCT on one block of samples.
+ */
+
+GLOBAL(void)
+fdct_ifast248 (DCTELEM * data)
+{
+ DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ DCTELEM tmp10, tmp11, tmp12, tmp13;
+ DCTELEM z1, z2, z3, z4, z5, z11, z13;
+ DCTELEM *dataptr;
+ int ctr;
+ SHIFT_TEMPS
+
+ /* Pass 1: process rows. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[0] + dataptr[7];
+ tmp7 = dataptr[0] - dataptr[7];
+ tmp1 = dataptr[1] + dataptr[6];
+ tmp6 = dataptr[1] - dataptr[6];
+ tmp2 = dataptr[2] + dataptr[5];
+ tmp5 = dataptr[2] - dataptr[5];
+ tmp3 = dataptr[3] + dataptr[4];
+ tmp4 = dataptr[3] - dataptr[4];
+
+ /* Even part */
+
+ tmp10 = tmp0 + tmp3; /* phase 2 */
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[0] = tmp10 + tmp11; /* phase 3 */
+ dataptr[4] = tmp10 - tmp11;
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
+ dataptr[2] = tmp13 + z1; /* phase 5 */
+ dataptr[6] = tmp13 - z1;
+
+ /* Odd part */
+
+ tmp10 = tmp4 + tmp5; /* phase 2 */
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp6 + tmp7;
+
+ /* The rotator is modified from fig 4-8 to avoid extra negations. */
+ z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
+ z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
+ z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
+ z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
+
+ z11 = tmp7 + z3; /* phase 5 */
+ z13 = tmp7 - z3;
+
+ dataptr[5] = z13 + z2; /* phase 6 */
+ dataptr[3] = z13 - z2;
+ dataptr[1] = z11 + z4;
+ dataptr[7] = z11 - z4;
+
+ dataptr += DCTSIZE; /* advance pointer to next row */
+ }
+
+ /* Pass 2: process columns. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*1];
+ tmp1 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*3];
+ tmp2 = dataptr[DCTSIZE*4] + dataptr[DCTSIZE*5];
+ tmp3 = dataptr[DCTSIZE*6] + dataptr[DCTSIZE*7];
+ tmp4 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*1];
+ tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*3];
+ tmp6 = dataptr[DCTSIZE*4] - dataptr[DCTSIZE*5];
+ tmp7 = dataptr[DCTSIZE*6] - dataptr[DCTSIZE*7];
+
+ /* Even part */
+
+ tmp10 = tmp0 + tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ tmp13 = tmp0 - tmp3;
+
+ dataptr[DCTSIZE*0] = tmp10 + tmp11;
+ dataptr[DCTSIZE*4] = tmp10 - tmp11;
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
+ dataptr[DCTSIZE*2] = tmp13 + z1;
+ dataptr[DCTSIZE*6] = tmp13 - z1;
+
+ tmp10 = tmp4 + tmp7;
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp5 - tmp6;
+ tmp13 = tmp4 - tmp7;
+
+ dataptr[DCTSIZE*1] = tmp10 + tmp11;
+ dataptr[DCTSIZE*5] = tmp10 - tmp11;
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
+ dataptr[DCTSIZE*3] = tmp13 + z1;
+ dataptr[DCTSIZE*7] = tmp13 - z1;
+
+ dataptr++; /* advance pointer to next column */
+ }
+}
+
#undef GLOBAL
#undef CONST_BITS