ffmpeg-2.8.5

git-svn-id: svn://kolibrios.org@6147 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/ffmpeg/ffmpeg-2.8/libavcodec/celp_math.c

@@ -0,0 +1,126 @@
+/*
+ * Various fixed-point math operations
+ *
+ * Copyright (c) 2008 Vladimir Voroshilov
+ *
+ * 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
+ */
+
+#include <inttypes.h>
+#include <limits.h>
+
+#include "libavutil/avassert.h"
+#include "avcodec.h"
+#include "mathops.h"
+#include "celp_math.h"
+#include "libavutil/common.h"
+
+static const uint16_t exp2a[]=
+{
+     0,  1435,  2901,  4400,  5931,  7496,  9096, 10730,
+ 12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160,
+ 27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320,
+ 44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727,
+};
+
+static const uint16_t exp2b[]=
+{
+     3,   712,  1424,  2134,  2845,  3557,  4270,  4982,
+  5696,  6409,  7124,  7839,  8554,  9270,  9986, 10704,
+ 11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455,
+ 17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238,
+};
+
+int ff_exp2(uint16_t power)
+{
+    unsigned int result= exp2a[power>>10] + 0x10000;
+
+    av_assert2(power <= 0x7fff);
+
+    result= (result<<3) + ((result*exp2b[(power>>5)&31])>>17);
+    return result + ((result*(power&31)*89)>>22);
+}
+
+/**
+ * Table used to compute log2(x)
+ *
+ * tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32
+ */
+static const uint16_t tab_log2[33] =
+{
+#ifdef G729_BITEXACT
+      0,   1455,   2866,   4236,   5568,   6863,   8124,   9352,
+  10549,  11716,  12855,  13967,  15054,  16117,  17156,  18172,
+  19167,  20142,  21097,  22033,  22951,  23852,  24735,  25603,
+  26455,  27291,  28113,  28922,  29716,  30497,  31266,  32023,  32767,
+#else
+      4,   1459,   2870,   4240,   5572,   6867,   8127,   9355,
+  10552,  11719,  12858,  13971,  15057,  16120,  17158,  18175,
+  19170,  20145,  21100,  22036,  22954,  23854,  24738,  25605,
+  26457,  27294,  28116,  28924,  29719,  30500,  31269,  32025,  32769,
+#endif
+};
+
+int ff_log2_q15(uint32_t value)
+{
+    uint8_t  power_int;
+    uint8_t  frac_x0;
+    uint16_t frac_dx;
+
+    // Stripping zeros from beginning
+    power_int = av_log2(value);
+    value <<= (31 - power_int);
+
+    // b31 is always non-zero now
+    frac_x0 = (value & 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31]
+    frac_dx = (value & 0x03fff800) >> 11;
+
+    value = tab_log2[frac_x0];
+    value += (frac_dx * (tab_log2[frac_x0+1] - tab_log2[frac_x0])) >> 15;
+
+    return (power_int << 15) + value;
+}
+
+int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length)
+{
+    int i;
+    int64_t sum = 0;
+
+    for (i = 0; i < length; i++)
+        sum += MUL16(a[i], b[i]);
+
+    return sum;
+}
+
+float ff_dot_productf(const float* a, const float* b, int length)
+{
+    float sum = 0;
+    int i;
+
+    for(i=0; i<length; i++)
+        sum += a[i] * b[i];
+
+    return sum;
+}
+
+void ff_celp_math_init(CELPMContext *c)
+{
+    c->dot_productf   = ff_dot_productf;
+
+    if(HAVE_MIPSFPU)
+        ff_celp_math_init_mips(c);
+}