dca: Convert dca_dmixtable to integers

Also include zero in the table, eliminating a special case in the
decoder.

Signed-off-by: Niels Möller <nisse@southpole.se>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

2 files changed, 42 insertions, 41 deletions

diff --git a/libavcodec/dcadata.h b/libavcodec/dcadata.h
index da3422e09b..28c40cf55e 100644
--- a/libavcodec/dcadata.h
+++ b/libavcodec/dcadata.h
@@ -7520,38 +7520,38 @@ DECLARE_ALIGNED(16, static const float, lfe_fir_128)[] =
  * 2) [-29.750 to -15] with resolution of 0.250 dB
  * 3) [-14.875 to   0] with resolution of 0.125 dB
  */
-static const float dca_dmixtable[241] = {
-    0.001000, 0.001059, 0.001122, 0.001189, 0.001259, 0.001334, 0.001413, 0.001496,
-    0.001585, 0.001679, 0.001778, 0.001884, 0.001995, 0.002113, 0.002239, 0.002371,
-    0.002512, 0.002661, 0.002818, 0.002985, 0.003162, 0.003350, 0.003548, 0.003758,
-    0.003981, 0.004217, 0.004467, 0.004732, 0.005012, 0.005309, 0.005623, 0.005957,
-    0.006310, 0.006683, 0.007079, 0.007499, 0.007943, 0.008414, 0.008913, 0.009441,
-    0.010000, 0.010593, 0.011220, 0.011885, 0.012589, 0.013335, 0.014125, 0.014962,
-    0.015849, 0.016788, 0.017783, 0.018836, 0.019953, 0.021135, 0.022387, 0.023714,
-    0.025119, 0.026607, 0.028184, 0.029854, 0.031623, 0.032546, 0.033497, 0.034475,
-    0.035481, 0.036517, 0.037584, 0.038681, 0.039811, 0.040973, 0.042170, 0.043401,
-    0.044668, 0.045973, 0.047315, 0.048697, 0.050119, 0.051582, 0.053088, 0.054639,
-    0.056234, 0.057876, 0.059566, 0.061306, 0.063096, 0.064938, 0.066834, 0.068786,
-    0.070795, 0.072862, 0.074989, 0.077179, 0.079433, 0.081752, 0.084140, 0.086596,
-    0.089125, 0.091728, 0.094406, 0.097163, 0.100000, 0.102920, 0.105925, 0.109018,
-    0.112202, 0.115478, 0.118850, 0.122321, 0.125893, 0.129569, 0.133352, 0.137246,
-    0.141254, 0.145378, 0.149624, 0.153993, 0.158489, 0.163117, 0.167880, 0.172783,
-    0.177828, 0.180406, 0.183021, 0.185674, 0.188365, 0.191095, 0.193865, 0.196675,
-    0.199526, 0.202418, 0.205353, 0.208329, 0.211349, 0.214412, 0.217520, 0.220673,
-    0.223872, 0.227117, 0.230409, 0.233749, 0.237137, 0.240575, 0.244062, 0.247600,
-    0.251189, 0.254830, 0.258523, 0.262271, 0.266073, 0.269929, 0.273842, 0.277811,
-    0.281838, 0.285924, 0.290068, 0.294273, 0.298538, 0.302866, 0.307256, 0.311709,
-    0.316228, 0.320812, 0.325462, 0.330179, 0.334965, 0.339821, 0.344747, 0.349744,
-    0.354813, 0.359956, 0.365174, 0.370467, 0.375837, 0.381285, 0.386812, 0.392419,
-    0.398107, 0.403878, 0.409732, 0.415671, 0.421697, 0.427809, 0.434010, 0.440301,
-    0.446684, 0.453158, 0.459727, 0.466391, 0.473151, 0.480010, 0.486968, 0.494026,
-    0.501187, 0.508452, 0.515822, 0.523299, 0.530884, 0.538580, 0.546387, 0.554307,
-    0.562341, 0.570493, 0.578762, 0.587151, 0.595662, 0.604296, 0.613056, 0.621942,
-    0.630957, 0.640103, 0.649382, 0.658795, 0.668344, 0.678032, 0.687860, 0.697831,
-    0.707107, 0.718208, 0.728618, 0.739180, 0.749894, 0.760764, 0.771792, 0.782979,
-    0.794328, 0.805842, 0.817523, 0.829373, 0.841395, 0.853591, 0.865964, 0.878517,
-    0.891251, 0.904170, 0.917276, 0.930572, 0.944061, 0.957745, 0.971628, 0.985712,
-    1.000000,
+static const uint16_t dca_dmixtable[242] = {
+    0,     33,    35,    37,    39,    41,    44,    46,
+    49,    52,    55,    58,    62,    65,    69,    73,
+    78,    82,    87,    92,    98,    104,   110,   116,
+    123,   130,   138,   146,   155,   164,   174,   184,
+    195,   207,   219,   232,   246,   260,   276,   292,
+    309,   328,   347,   368,   389,   413,   437,   463,
+    490,   519,   550,   583,   617,   654,   693,   734,
+    777,   823,   872,   924,   978,   1036,  1066,  1098,
+    1130,  1163,  1197,  1232,  1268,  1305,  1343,  1382,
+    1422,  1464,  1506,  1550,  1596,  1642,  1690,  1740,
+    1790,  1843,  1896,  1952,  2009,  2068,  2128,  2190,
+    2254,  2320,  2388,  2457,  2529,  2603,  2679,  2757,
+    2838,  2920,  3006,  3093,  3184,  3277,  3372,  3471,
+    3572,  3677,  3784,  3894,  4008,  4125,  4246,  4370,
+    4497,  4629,  4764,  4903,  5046,  5193,  5345,  5501,
+    5662,  5827,  5912,  5997,  6084,  6172,  6262,  6353,
+    6445,  6538,  6633,  6729,  6827,  6925,  7026,  7128,
+    7231,  7336,  7442,  7550,  7659,  7771,  7883,  7997,
+    8113,  8231,  8350,  8471,  8594,  8719,  8845,  8973,
+    9103,  9235,  9369,  9505,  9643,  9783,  9924,  10068,
+    10214, 10362, 10512, 10665, 10819, 10976, 11135, 11297,
+    11460, 11627, 11795, 11966, 12139, 12315, 12494, 12675,
+    12859, 13045, 13234, 13426, 13621, 13818, 14018, 14222,
+    14428, 14637, 14849, 15064, 15283, 15504, 15729, 15957,
+    16188, 16423, 16661, 16902, 17147, 17396, 17648, 17904,
+    18164, 18427, 18694, 18965, 19240, 19519, 19802, 20089,
+    20380, 20675, 20975, 21279, 21587, 21900, 22218, 22540,
+    22867, 23170, 23534, 23875, 24221, 24573, 24929, 25290,
+    25657, 26029, 26406, 26789, 27177, 27571, 27970, 28376,
+    28787, 29205, 29628, 30057, 30493, 30935, 31383, 31838,
+    32300, 32768,
 };
 
 static const float dca_default_coeffs[10][6][2] = {
diff --git a/libavcodec/dcadec.c b/libavcodec/dcadec.c
index c8877d6d1f..0727857bb6 100644
--- a/libavcodec/dcadec.c
+++ b/libavcodec/dcadec.c
@@ -1695,6 +1695,13 @@ static void dca_exss_parse_header(DCAContext *s)
      * from the asset header */
 }
 
+static float dca_dmix_code(unsigned code)
+{
+    int sign = (code >> 8) - 1;
+    code &= 0xff;
+    return ldexpf((dca_dmixtable[code] ^ sign) - sign, -15);
+}
+
 /**
  * Main frame decoding function
  * FIXME add arguments
@@ -1902,16 +1909,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
              */
             if (s->core_downmix && (s->core_downmix_amode == DCA_STEREO ||
                                     s->core_downmix_amode == DCA_STEREO_TOTAL)) {
-                int sign, code;
                 for (i = 0; i < num_core_channels + !!s->lfe; i++) {
-                    sign = s->core_downmix_codes[i][0] & 0x100 ? 1 : -1;
-                    code = s->core_downmix_codes[i][0] & 0x0FF;
-                    s->downmix_coef[i][0] = (!code ? 0.0f :
-                                             sign * dca_dmixtable[code - 1]);
-                    sign = s->core_downmix_codes[i][1] & 0x100 ? 1 : -1;
-                    code = s->core_downmix_codes[i][1] & 0x0FF;
-                    s->downmix_coef[i][1] = (!code ? 0.0f :
-                                             sign * dca_dmixtable[code - 1]);
+                    /* Range checked earlier */
+                    s->downmix_coef[i][0] = dca_dmix_code(s->core_downmix_codes[i][0]);
+                    s->downmix_coef[i][1] = dca_dmix_code(s->core_downmix_codes[i][1]);
                 }
                 s->output = s->core_downmix_amode;
             } else {