Also include zero in the table, eliminating a special case in the
decoder.
Signed-off-by: Niels Möller <[email protected]>
---
This is a small step towards integer decoding, needed for other work on
7.1 xll. I think it's fairly safe. Passes make fate-dts (any other easy
regression testing I can do?). Also has the nice effect of shrinking the
table from 964 to 484 bytes. The table values are copied from the spec
(thanks pdf2txt), not derived from the earlier float values.
libavcodec/dcadata.h | 64 ++++++++++++++++++++++++++--------------------------
libavcodec/dcadec.c | 19 ++++++++--------
2 files changed, 42 insertions(+), 41 deletions(-)
diff --git a/libavcodec/dcadata.h b/libavcodec/dcadata.h
index da3422e..28c40cf 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 c8877d6..0727857 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 {
--
1.8.3.2
--
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
Internet email is subject to wholesale government surveillance.
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