Electronic Arts TGQ/TQI/MAD IDCT algorithm

Originally committed as revision 15790 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 87 insertions, 0 deletions

diff --git a/libavcodec/eaidct.c b/libavcodec/eaidct.c
new file mode 100644
index 0000000000..8a243508f5
--- /dev/null
+++ b/libavcodec/eaidct.c
@@ -0,0 +1,87 @@
+/*
+ * Electronic Arts TGQ/TQI/MAD IDCT algorithm
+ * Copyright (c) 2007-2008 Peter Ross <pross@xvid.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file eaidct.c
+ * Electronic Arts TGQ/TQI/MAD IDCT algorithm
+ * @author Peter Ross <pross@xvid.org>
+ */
+
+#include "dsputil.h"
+
+#define ASQRT 181 /* (1/sqrt(2))<<8 */
+#define A4    669 /* cos(pi/8)*sqrt(2)<<9 */
+#define A2    277 /* sin(pi/8)*sqrt(2)<<9 */
+#define A5    196 /* sin(pi/8)<<9 */
+
+#define IDCT_TRANSFORM(dest,s0,s1,s2,s3,s4,s5,s6,s7,d0,d1,d2,d3,d4,d5,d6,d7,munge,src) {\
+    const int a1 = (src)[s1] + (src)[s7]; \
+    const int a7 = (src)[s1] - (src)[s7]; \
+    const int a5 = (src)[s5] + (src)[s3]; \
+    const int a3 = (src)[s5] - (src)[s3]; \
+    const int a2 = (src)[s2] + (src)[s6]; \
+    const int a6 = (ASQRT*((src)[s2] - (src)[s6]))>>8; \
+    const int a0 = (src)[s0] + (src)[s4]; \
+    const int a4 = (src)[s0] - (src)[s4]; \
+    const int b0 = (((A4-A5)*a7 - A5*a3)>>9) + a1+a5; \
+    const int b1 = (((A4-A5)*a7 - A5*a3)>>9) + ((ASQRT*(a1-a5))>>8); \
+    const int b2 = (((A2+A5)*a3 + A5*a7)>>9) + ((ASQRT*(a1-a5))>>8); \
+    const int b3 =  ((A2+A5)*a3 + A5*a7)>>9; \
+    (dest)[d0] = munge(a0+a2+a6+b0); \
+    (dest)[d1] = munge(a4+a6   +b1); \
+    (dest)[d2] = munge(a4-a6   +b2); \
+    (dest)[d3] = munge(a0-a2-a6+b3); \
+    (dest)[d4] = munge(a0-a2-a6-b3); \
+    (dest)[d5] = munge(a4-a6   -b2); \
+    (dest)[d6] = munge(a4+a6   -b1); \
+    (dest)[d7] = munge(a0+a2+a6-b0); \
+}
+/* end IDCT_TRANSFORM macro */
+
+#define MUNGE_NONE(x) (x)
+#define IDCT_COL(dest,src) IDCT_TRANSFORM(dest,0,8,16,24,32,40,48,56,0,8,16,24,32,40,48,56,MUNGE_NONE,src)
+
+#define MUNGE_8BIT(x) av_clip_uint8((x)>>4)
+#define IDCT_ROW(dest,src) IDCT_TRANSFORM(dest,0,1,2,3,4,5,6,7,0,1,2,3,4,5,6,7,MUNGE_8BIT,src)
+
+static inline void ea_idct_col(DCTELEM *dest, const DCTELEM *src) {
+    if ((src[8]|src[16]|src[24]|src[32]|src[40]|src[48]|src[56])==0) {
+        dest[0]  =
+        dest[8]  =
+        dest[16] =
+        dest[24] =
+        dest[32] =
+        dest[40] =
+        dest[48] =
+        dest[56] = src[0];
+    }else
+        IDCT_COL(dest, src);
+}
+
+void ff_ea_idct_put_c(uint8_t *dest, int linesize, DCTELEM *block) {
+    int i;
+    DCTELEM temp[64];
+    block[0] += 4;
+    for (i=0; i<8; i++)
+        ea_idct_col(&temp[i], &block[i]);
+    for (i=0; i<8; i++)
+        IDCT_ROW( (&dest[i*linesize]), (&temp[8*i]) );
+}