aboutsummaryrefslogblamecommitdiffstats
path: root/libavcodec/g723_1.c
blob: e1dc431d0e7d6e5fc6a2b1621d0c1259842d4ec9 (plain) (tree)
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181



























































                                                                               









                                                                     



















































































                                                                                


                                               
                                 
                                                 











































                                                                              
                                           










                                                                          




                        
                                   


             


                                                         


















                                                                       
                                             















































































                                                                                
                    
























































































































































































































                                                                              
                                                                 






















                                                                              
                                                            
































































































                                                                        
                                                          


                                                                
                                                    


                                                                  
                                                    


























































                                                                           
                                                             





                                                         
                                                   























































































































































                                                                               
                                                           
                                                               
                                                       



































































































































































                                                                                 






































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                  
                                                                      
































                                                                              
/*
 * G.723.1 compatible decoder
 * Copyright (c) 2006 Benjamin Larsson
 * Copyright (c) 2010 Mohamed Naufal Basheer
 *
 * 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
 * G.723.1 compatible decoder
 */

#include "avcodec.h"
#define ALT_BITSTREAM_READER_LE
#include "get_bits.h"
#include "acelp_vectors.h"
#include "celp_filters.h"
#include "celp_math.h"
#include "lsp.h"
#include "libavutil/lzo.h"
#include "g723_1_data.h"

typedef struct g723_1_context {
    G723_1_Subframe subframe[4];
    FrameType cur_frame_type;
    FrameType past_frame_type;
    Rate cur_rate;
    uint8_t lsp_index[LSP_BANDS];
    int pitch_lag[2];
    int erased_frames;

    int16_t prev_lsp[LPC_ORDER];
    int16_t prev_excitation[PITCH_MAX];
    int16_t excitation[PITCH_MAX + FRAME_LEN];
    int16_t synth_mem[LPC_ORDER];
    int16_t fir_mem[LPC_ORDER];
    int     iir_mem[LPC_ORDER];

    int random_seed;
    int interp_index;
    int interp_gain;
    int sid_gain;
    int cur_gain;
    int reflection_coef;
    int pf_gain;                 ///< formant postfilter
                                 ///< gain scaling unit memory

    int16_t prev_data[HALF_FRAME_LEN];
    int16_t prev_weight_sig[PITCH_MAX];


    int16_t hpf_fir_mem;                   ///< highpass filter fir
    int     hpf_iir_mem;                   ///< and iir memories
    int16_t perf_fir_mem[LPC_ORDER];       ///< perceptual filter fir
    int16_t perf_iir_mem[LPC_ORDER];       ///< and iir memories

    int16_t harmonic_mem[PITCH_MAX];
} G723_1_Context;

static av_cold int g723_1_decode_init(AVCodecContext *avctx)
{
    G723_1_Context *p  = avctx->priv_data;

    avctx->sample_fmt  = SAMPLE_FMT_S16;
    p->pf_gain         = 1 << 12;
    memcpy(p->prev_lsp, dc_lsp, LPC_ORDER * sizeof(int16_t));

    return 0;
}

/**
 * Unpack the frame into parameters.
 *
 * @param p           the context
 * @param buf         pointer to the input buffer
 * @param buf_size    size of the input buffer
 */
static int unpack_bitstream(G723_1_Context *p, const uint8_t *buf,
                            int buf_size)
{
    GetBitContext gb;
    int ad_cb_len;
    int temp, info_bits, i;

    init_get_bits(&gb, buf, buf_size * 8);

    /* Extract frame type and rate info */
    info_bits = get_bits(&gb, 2);

    if (info_bits == 3) {
        p->cur_frame_type = UntransmittedFrame;
        return 0;
    }

    /* Extract 24 bit lsp indices, 8 bit for each band */
    p->lsp_index[2] = get_bits(&gb, 8);
    p->lsp_index[1] = get_bits(&gb, 8);
    p->lsp_index[0] = get_bits(&gb, 8);

    if (info_bits == 2) {
        p->cur_frame_type = SIDFrame;
        p->subframe[0].amp_index = get_bits(&gb, 6);
        return 0;
    }

    /* Extract the info common to both rates */
    p->cur_rate       = info_bits ? Rate5k3 : Rate6k3;
    p->cur_frame_type = ActiveFrame;

    p->pitch_lag[0] = get_bits(&gb, 7);
    if (p->pitch_lag[0] > 123)       /* test if forbidden code */
        return -1;
    p->pitch_lag[0] += PITCH_MIN;
    p->subframe[1].ad_cb_lag = get_bits(&gb, 2);

    p->pitch_lag[1] = get_bits(&gb, 7);
    if (p->pitch_lag[1] > 123)
        return -1;
    p->pitch_lag[1] += PITCH_MIN;
    p->subframe[3].ad_cb_lag = get_bits(&gb, 2);
    p->subframe[0].ad_cb_lag = 1;
    p->subframe[2].ad_cb_lag = 1;

    for (i = 0; i < SUBFRAMES; i++) {
        /* Extract combined gain */
        temp = get_bits(&gb, 12);
        ad_cb_len = 170;
        p->subframe[i].dirac_train = 0;
        if (p->cur_rate == Rate6k3 && p->pitch_lag[i >> 1] < SUBFRAME_LEN - 2) {
            p->subframe[i].dirac_train = temp >> 11;
            temp &= 0x7ff;
            ad_cb_len = 85;
        }
        p->subframe[i].ad_cb_gain = FASTDIV(temp, GAIN_LEVELS);
        if (p->subframe[i].ad_cb_gain < ad_cb_len) {
            p->subframe[i].amp_index = temp - p->subframe[i].ad_cb_gain *
                                       GAIN_LEVELS;
        } else {
            return -1;
        }
    }

    p->subframe[0].grid_index = get_bits1(&gb);
    p->subframe[1].grid_index = get_bits1(&gb);
    p->subframe[2].grid_index = get_bits1(&gb);
    p->subframe[3].grid_index = get_bits1(&gb);

    if (p->cur_rate == Rate6k3) {
        skip_bits1(&gb);  /* skip reserved bit */

        /* Compute pulse_pos index using the 13-bit combined position index */
        temp = get_bits(&gb, 13);
        p->subframe[0].pulse_pos = temp / 810;

        temp -= p->subframe[0].pulse_pos * 810;
        p->subframe[1].pulse_pos = FASTDIV(temp, 90);

        temp -= p->subframe[1].pulse_pos * 90;
        p->subframe[2].pulse_pos = FASTDIV(temp, 9);
        p->subframe[3].pulse_pos = temp - p->subframe[2].pulse_pos * 9;

        p->subframe[0].pulse_pos = (p->subframe[0].pulse_pos << 16) +
                                   get_bits(&gb, 16);
        p->subframe[1].pulse_pos = (p->subframe[1].pulse_pos << 14) +
                                   get_bits(&gb, 14);
        p->subframe[2].pulse_pos = (p->subframe[2].pulse_pos << 16) +
                                   get_bits(&gb, 16);
        p->subframe[3].pulse_pos = (p->subframe[3].pulse_pos << 14) +
                                   get_bits(&gb, 14);

        p->subframe[0].pulse_sign = get_bits(&gb, 6);
        p->subframe[1].pulse_sign = get_bits(&gb, 5);
        p->subframe[2].pulse_sign = get_bits(&gb, 6);
        p->subframe[3].pulse_sign = get_bits(&gb, 5);
    } else { /* Rate5k3 */
        p->subframe[0].pulse_pos  = get_bits(&gb, 12);
        p->subframe[1].pulse_pos  = get_bits(&gb, 12);
        p->subframe[2].pulse_pos  = get_bits(&gb, 12);
        p->subframe[3].pulse_pos  = get_bits(&gb, 12);

        p->subframe[0].pulse_sign = get_bits(&gb, 4);
        p->subframe[1].pulse_sign = get_bits(&gb, 4);
        p->subframe[2].pulse_sign = get_bits(&gb, 4);
        p->subframe[3].pulse_sign = get_bits(&gb, 4);
    }

    return 0;
}

/**
 * Bitexact implementation of sqrt(val/2).
 */
static int16_t square_root(int val)
{
    return (ff_sqrt(val << 1) >> 1) & (~1);
}

/**
 * Calculate the number of left-shifts required for normalizing the input.
 *
 * @param num   input number
 * @param width width of the input, 16 bits(0) / 32 bits(1)
 */
static int normalize_bits(int num, int width)
{
    int i = 0;
    int bits = (width) ? 31 : 15;

    if (num) {
        if (num == -1)
            return bits;
        if (num < 0)
            num = ~num;
        i= bits - av_log2(num) - 1;
        i= FFMAX(i, 0);
    }
    return i;
}

#define normalize_bits_int16(num) normalize_bits(num, 0)
#define normalize_bits_int32(num) normalize_bits(num, 1)
#define dot_product(a,b,c,d) (ff_dot_product(a,b,c)<<(d))

/**
 * Scale vector contents based on the largest of their absolutes.
 */
static int scale_vector(int16_t *vector, int length)
{
    int bits, scale, max = 0;
    int i;

    const int16_t shift_table[16] = {
        0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
        0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000, 0x7fff
    };

    for (i = 0; i < length; i++)
        max = FFMAX(max, FFABS(vector[i]));

    bits  = normalize_bits(max, 0);
    scale = shift_table[bits];

    for (i = 0; i < length; i++)
        vector[i] = (vector[i] * scale) >> 3;

    return bits - 3;
}

/**
 * Perform inverse quantization of LSP frequencies.
 *
 * @param cur_lsp    the current LSP vector
 * @param prev_lsp   the previous LSP vector
 * @param lsp_index  VQ indices
 * @param bad_frame  bad frame flag
 */
static void inverse_quant(int16_t *cur_lsp, int16_t *prev_lsp,
                          uint8_t *lsp_index, int bad_frame)
{
    int min_dist, pred;
    int i, j, temp, stable;

    /* Check for frame erasure */
    if (!bad_frame) {
        min_dist     = 0x100;
        pred         = 12288;
    } else {
        min_dist     = 0x200;
        pred         = 23552;
        lsp_index[0] = lsp_index[1] = lsp_index[2] = 0;
    }

    /* Get the VQ table entry corresponding to the transmitted index */
    cur_lsp[0] = lsp_band0[lsp_index[0]][0];
    cur_lsp[1] = lsp_band0[lsp_index[0]][1];
    cur_lsp[2] = lsp_band0[lsp_index[0]][2];
    cur_lsp[3] = lsp_band1[lsp_index[1]][0];
    cur_lsp[4] = lsp_band1[lsp_index[1]][1];
    cur_lsp[5] = lsp_band1[lsp_index[1]][2];
    cur_lsp[6] = lsp_band2[lsp_index[2]][0];
    cur_lsp[7] = lsp_band2[lsp_index[2]][1];
    cur_lsp[8] = lsp_band2[lsp_index[2]][2];
    cur_lsp[9] = lsp_band2[lsp_index[2]][3];

    /* Add predicted vector & DC component to the previously quantized vector */
    for (i = 0; i < LPC_ORDER; i++) {
        temp        = ((prev_lsp[i] - dc_lsp[i]) * pred + (1 << 14)) >> 15;
        cur_lsp[i] += dc_lsp[i] + temp;
    }

    for (i = 0; i < LPC_ORDER; i++) {
        cur_lsp[0]             = FFMAX(cur_lsp[0],  0x180);
        cur_lsp[LPC_ORDER - 1] = FFMIN(cur_lsp[LPC_ORDER - 1], 0x7e00);

        /* Stability check */
        for (j = 1; j < LPC_ORDER; j++) {
            temp = min_dist + cur_lsp[j - 1] - cur_lsp[j];
            if (temp > 0) {
                temp >>= 1;
                cur_lsp[j - 1] -= temp;
                cur_lsp[j]     += temp;
            }
        }
        stable = 1;
        for (j = 1; j < LPC_ORDER; j++) {
            temp = cur_lsp[j - 1] + min_dist - cur_lsp[j] - 4;
            if (temp > 0) {
                stable = 0;
                break;
            }
        }
        if (stable)
            break;
    }
    if (!stable)
        memcpy(cur_lsp, prev_lsp, LPC_ORDER * sizeof(int16_t));
}

/**
 * Bitexact implementation of 2ab scaled by 1/2^16.
 *
 * @param a 32 bit multiplicand
 * @param b 16 bit multiplier
 */
#define MULL2(a, b) \
        MULL(a,b,15)

/**
 * Convert LSP frequencies to LPC coefficients.
 *
 * @param lpc buffer for LPC coefficients
 */
static void lsp2lpc(int16_t *lpc)
{
    int f1[LPC_ORDER / 2 + 1];
    int f2[LPC_ORDER / 2 + 1];
    int i, j;

    /* Calculate negative cosine */
    for (j = 0; j < LPC_ORDER; j++) {
        int index     = lpc[j] >> 7;
        int offset    = lpc[j] & 0x7f;
        int64_t temp1 = cos_tab[index] << 16;
        int temp2     = (cos_tab[index + 1] - cos_tab[index]) *
                          ((offset << 8) + 0x80) << 1;

        lpc[j] = -(av_clipl_int32(((temp1 + temp2) << 1) + (1 << 15)) >> 16);
    }

    /*
     * Compute sum and difference polynomial coefficients
     * (bitexact alternative to lsp2poly() in lsp.c)
     */
    /* Initialize with values in Q28 */
    f1[0] = 1 << 28;
    f1[1] = (lpc[0] << 14) + (lpc[2] << 14);
    f1[2] = lpc[0] * lpc[2] + (2 << 28);

    f2[0] = 1 << 28;
    f2[1] = (lpc[1] << 14) + (lpc[3] << 14);
    f2[2] = lpc[1] * lpc[3] + (2 << 28);

    /*
     * Calculate and scale the coefficients by 1/2 in
     * each iteration for a final scaling factor of Q25
     */
    for (i = 2; i < LPC_ORDER / 2; i++) {
        f1[i + 1] = f1[i - 1] + MULL2(f1[i], lpc[2 * i]);
        f2[i + 1] = f2[i - 1] + MULL2(f2[i], lpc[2 * i + 1]);

        for (j = i; j >= 2; j--) {
            f1[j] = MULL2(f1[j - 1], lpc[2 * i]) +
                    (f1[j] >> 1) + (f1[j - 2] >> 1);
            f2[j] = MULL2(f2[j - 1], lpc[2 * i + 1]) +
                    (f2[j] >> 1) + (f2[j - 2] >> 1);
        }

        f1[0] >>= 1;
        f2[0] >>= 1;
        f1[1] = ((lpc[2 * i]     << 16 >> i) + f1[1]) >> 1;
        f2[1] = ((lpc[2 * i + 1] << 16 >> i) + f2[1]) >> 1;
    }

    /* Convert polynomial coefficients to LPC coefficients */
    for (i = 0; i < LPC_ORDER / 2; i++) {
        int64_t ff1 = f1[i + 1] + f1[i];
        int64_t ff2 = f2[i + 1] - f2[i];

        lpc[i] = av_clipl_int32(((ff1 + ff2) << 3) + (1 << 15)) >> 16;
        lpc[LPC_ORDER - i - 1] = av_clipl_int32(((ff1 - ff2) << 3) +
                                                (1 << 15)) >> 16;
    }
}

/**
 * Quantize LSP frequencies by interpolation and convert them to
 * the corresponding LPC coefficients.
 *
 * @param lpc      buffer for LPC coefficients
 * @param cur_lsp  the current LSP vector
 * @param prev_lsp the previous LSP vector
 */
static void lsp_interpolate(int16_t *lpc, int16_t *cur_lsp, int16_t *prev_lsp)
{
    int i;
    int16_t *lpc_ptr = lpc;

    /* cur_lsp * 0.25 + prev_lsp * 0.75 */
    ff_acelp_weighted_vector_sum(lpc, cur_lsp, prev_lsp,
                                 4096, 12288, 1 << 13, 14, LPC_ORDER);
    ff_acelp_weighted_vector_sum(lpc + LPC_ORDER, cur_lsp, prev_lsp,
                                 8192, 8192, 1 << 13, 14, LPC_ORDER);
    ff_acelp_weighted_vector_sum(lpc + 2 * LPC_ORDER, cur_lsp, prev_lsp,
                                 12288, 4096, 1 << 13, 14, LPC_ORDER);
    memcpy(lpc + 3 * LPC_ORDER, cur_lsp, LPC_ORDER * sizeof(int16_t));

    for (i = 0; i < SUBFRAMES; i++) {
        lsp2lpc(lpc_ptr);
        lpc_ptr += LPC_ORDER;
    }
}

/**
 * Generate a train of dirac functions with period as pitch lag.
 */
static void gen_dirac_train(int16_t *buf, int pitch_lag)
{
    int16_t vector[SUBFRAME_LEN];
    int i, j;

    memcpy(vector, buf, SUBFRAME_LEN * sizeof(int16_t));
    for (i = pitch_lag; i < SUBFRAME_LEN; i += pitch_lag) {
        for (j = 0; j < SUBFRAME_LEN - i; j++)
            buf[i + j] += vector[j];
    }
}

/**
 * Generate fixed codebook excitation vector.
 *
 * @param vector    decoded excitation vector
 * @param subfrm    current subframe
 * @param cur_rate  current bitrate
 * @param pitch_lag closed loop pitch lag
 * @param index     current subframe index
 */
static void gen_fcb_excitation(int16_t *vector, G723_1_Subframe subfrm,
                               Rate cur_rate, int pitch_lag, int index)
{
    int temp, i, j;

    memset(vector, 0, SUBFRAME_LEN * sizeof(int16_t));

    if (cur_rate == Rate6k3) {
        if (subfrm.pulse_pos >= max_pos[index])
            return;

        /* Decode amplitudes and positions */
        j = PULSE_MAX - pulses[index];
        temp = subfrm.pulse_pos;
        for (i = 0; i < SUBFRAME_LEN / GRID_SIZE; i++) {
            temp -= combinatorial_table[j][i];
            if (temp >= 0)
                continue;
            temp += combinatorial_table[j++][i];
            if (subfrm.pulse_sign & (1 << (PULSE_MAX - j))) {
                vector[subfrm.grid_index + GRID_SIZE * i] =
                                        -fixed_cb_gain[subfrm.amp_index];
            } else {
                vector[subfrm.grid_index + GRID_SIZE * i] =
                                         fixed_cb_gain[subfrm.amp_index];
            }
            if (j == PULSE_MAX)
                break;
        }
        if (subfrm.dirac_train == 1)
            gen_dirac_train(vector, pitch_lag);
    } else { /* Rate5k3 */
        int cb_gain  = fixed_cb_gain[subfrm.amp_index];
        int cb_shift = subfrm.grid_index;
        int cb_sign  = subfrm.pulse_sign;
        int cb_pos   = subfrm.pulse_pos;
        int offset, beta, lag;

        for (i = 0; i < 8; i += 2) {
            offset         = ((cb_pos & 7) << 3) + cb_shift + i;
            vector[offset] = (cb_sign & 1) ? cb_gain : -cb_gain;
            cb_pos  >>= 3;
            cb_sign >>= 1;
        }

        /* Enhance harmonic components */
        lag  = pitch_contrib[subfrm.ad_cb_gain << 1] + pitch_lag +
               subfrm.ad_cb_lag - 1;
        beta = pitch_contrib[(subfrm.ad_cb_gain << 1) + 1];

        if (lag < SUBFRAME_LEN - 2) {
            for (i = lag; i < SUBFRAME_LEN; i++)
                vector[i] += beta * vector[i - lag] >> 15;
        }
    }
}

/**
 * Get delayed contribution from the previous excitation vector.
 */
static void get_residual(int16_t *residual, int16_t *prev_excitation, int lag)
{
    int offset = PITCH_MAX - PITCH_ORDER / 2 - lag;
    int i;

    residual[0] = prev_excitation[offset];
    residual[1] = prev_excitation[offset + 1];

    offset += 2;
    for (i = 2; i < SUBFRAME_LEN + PITCH_ORDER - 1; i++)
        residual[i] = prev_excitation[offset + (i - 2) % lag];
}

/**
 * Generate adaptive codebook excitation.
 */
static void gen_acb_excitation(int16_t *vector, int16_t *prev_excitation,
                               int pitch_lag, G723_1_Subframe subfrm,
                               Rate cur_rate)
{
    int16_t residual[SUBFRAME_LEN + PITCH_ORDER - 1];
    const int16_t *cb_ptr;
    int lag = pitch_lag + subfrm.ad_cb_lag - 1;

    int i;
    int64_t sum;

    get_residual(residual, prev_excitation, lag);

    /* Select quantization table */
    if (cur_rate == Rate6k3 && pitch_lag < SUBFRAME_LEN - 2) {
        cb_ptr = adaptive_cb_gain85;
    } else
        cb_ptr = adaptive_cb_gain170;

    /* Calculate adaptive vector */
    cb_ptr += subfrm.ad_cb_gain * 20;
    for (i = 0; i < SUBFRAME_LEN; i++) {
        sum = ff_dot_product(residual + i, cb_ptr, PITCH_ORDER);
        vector[i] = av_clipl_int32((sum << 2) + (1 << 15)) >> 16;
    }
}

/**
 * Estimate maximum auto-correlation around pitch lag.
 *
 * @param p         the context
 * @param offset    offset of the excitation vector
 * @param ccr_max   pointer to the maximum auto-correlation
 * @param pitch_lag decoded pitch lag
 * @param length    length of autocorrelation
 * @param dir       forward lag(1) / backward lag(-1)
 */
static int autocorr_max(G723_1_Context *p, int offset, int *ccr_max,
                        int pitch_lag, int length, int dir)
{
    int limit, ccr, lag = 0;
    int16_t *buf = p->excitation + offset;
    int i;

    pitch_lag = FFMIN(PITCH_MAX - 3, pitch_lag);
    limit     = FFMIN(FRAME_LEN + PITCH_MAX - offset - length, pitch_lag + 3);

    for (i = pitch_lag - 3; i <= limit; i++) {
        ccr = ff_dot_product(buf, buf + dir * i, length)<<1;

        if (ccr > *ccr_max) {
            *ccr_max = ccr;
            lag = i;
        }
    }
    return lag;
}

/**
 * Calculate pitch postfilter optimal and scaling gains.
 *
 * @param lag      pitch postfilter forward/backward lag
 * @param ppf      pitch postfilter parameters
 * @param cur_rate current bitrate
 * @param tgt_eng  target energy
 * @param ccr      cross-correlation
 * @param res_eng  residual energy
 */
static void comp_ppf_gains(int lag, PPFParam *ppf, Rate cur_rate,
                           int tgt_eng, int ccr, int res_eng)
{
    int pf_residual;     /* square of postfiltered residual */
    int64_t temp1, temp2;

    ppf->index = lag;

    temp1 = tgt_eng * res_eng >> 1;
    temp2 = ccr * ccr << 1;

    if (temp2 > temp1) {
        if (ccr >= res_eng) {
            ppf->opt_gain = ppf_gain_weight[cur_rate];
        } else {
            ppf->opt_gain = (ccr << 15) / res_eng *
                            ppf_gain_weight[cur_rate] >> 15;
        }
        /* pf_res^2 = tgt_eng + 2*ccr*gain + res_eng*gain^2 */
        temp1       = (tgt_eng << 15) + (ccr * ppf->opt_gain << 1);
        temp2       = (ppf->opt_gain * ppf->opt_gain >> 15) * res_eng;
        pf_residual = av_clipl_int32(temp1 + temp2 + (1 << 15)) >> 16;

        if (tgt_eng >= pf_residual << 1) {
            temp1 = 0x7fff;
        } else {
            temp1 = (tgt_eng << 14) / pf_residual;
        }

        /* scaling_gain = sqrt(tgt_eng/pf_res^2) */
        ppf->sc_gain = square_root(temp1 << 16);
    } else {
        ppf->opt_gain = 0;
        ppf->sc_gain  = 0x7fff;
    }

    ppf->opt_gain = av_clip_int16(ppf->opt_gain * ppf->sc_gain >> 15);
}

/**
 * Calculate pitch postfilter parameters.
 *
 * @param p         the context
 * @param offset    offset of the excitation vector
 * @param pitch_lag decoded pitch lag
 * @param ppf       pitch postfilter parameters
 * @param cur_rate  current bitrate
 */
static void comp_ppf_coeff(G723_1_Context *p, int offset, int pitch_lag,
                           PPFParam *ppf, Rate cur_rate)
{

    int16_t scale;
    int i;
    int64_t temp1, temp2;

    /*
     * 0 - target energy
     * 1 - forward cross-correlation
     * 2 - forward residual energy
     * 3 - backward cross-correlation
     * 4 - backward residual energy
     */
    int energy[5] = {0, 0, 0, 0, 0};
    int16_t *buf  = p->excitation + offset;
    int fwd_lag   = autocorr_max(p, offset, &energy[1], pitch_lag,
                                 SUBFRAME_LEN, 1);
    int back_lag  = autocorr_max(p, offset, &energy[3], pitch_lag,
                                 SUBFRAME_LEN, -1);

    ppf->index    = 0;
    ppf->opt_gain = 0;
    ppf->sc_gain  = 0x7fff;

    /* Case 0, Section 3.6 */
    if (!back_lag && !fwd_lag)
        return;

    /* Compute target energy */
    energy[0] = ff_dot_product(buf, buf, SUBFRAME_LEN)<<1;

    /* Compute forward residual energy */
    if (fwd_lag)
        energy[2] = ff_dot_product(buf + fwd_lag, buf + fwd_lag,
                                   SUBFRAME_LEN)<<1;

    /* Compute backward residual energy */
    if (back_lag)
        energy[4] = ff_dot_product(buf - back_lag, buf - back_lag,
                                   SUBFRAME_LEN)<<1;

    /* Normalize and shorten */
    temp1 = 0;
    for (i = 0; i < 5; i++)
        temp1 = FFMAX(energy[i], temp1);

    scale = normalize_bits(temp1, 1);
    for (i = 0; i < 5; i++)
        energy[i] = av_clipl_int32(energy[i] << scale) >> 16;

    if (fwd_lag && !back_lag) {  /* Case 1 */
        comp_ppf_gains(fwd_lag,  ppf, cur_rate, energy[0], energy[1],
                       energy[2]);
    } else if (!fwd_lag) {       /* Case 2 */
        comp_ppf_gains(-back_lag, ppf, cur_rate, energy[0], energy[3],
                       energy[4]);
    } else {                     /* Case 3 */

        /*
         * Select the largest of energy[1]^2/energy[2]
         * and energy[3]^2/energy[4]
         */
        temp1 = energy[4] * ((energy[1] * energy[1] + (1 << 14)) >> 15);
        temp2 = energy[2] * ((energy[3] * energy[3] + (1 << 14)) >> 15);
        if (temp1 >= temp2) {
            comp_ppf_gains(fwd_lag, ppf, cur_rate, energy[0], energy[1],
                           energy[2]);
        } else {
            comp_ppf_gains(-back_lag, ppf, cur_rate, energy[0], energy[3],
                           energy[4]);
        }
    }
}

/**
 * Classify frames as voiced/unvoiced.
 *
 * @param p         the context
 * @param pitch_lag decoded pitch_lag
 * @param exc_eng   excitation energy estimation
 * @param scale     scaling factor of exc_eng
 *
 * @return residual interpolation index if voiced, 0 otherwise
 */
static int comp_interp_index(G723_1_Context *p, int pitch_lag,
                             int *exc_eng, int *scale)
{
    int offset = PITCH_MAX + 2 * SUBFRAME_LEN;
    int16_t *buf = p->excitation + offset;

    int index, ccr, tgt_eng, best_eng, temp;

    *scale = scale_vector(p->excitation, FRAME_LEN + PITCH_MAX);

    /* Compute maximum backward cross-correlation */
    ccr   = 0;
    index = autocorr_max(p, offset, &ccr, pitch_lag, SUBFRAME_LEN * 2, -1);
    ccr   = av_clipl_int32((int64_t)ccr + (1 << 15)) >> 16;

    /* Compute target energy */
    tgt_eng  = ff_dot_product(buf, buf, SUBFRAME_LEN * 2)<<1;
    *exc_eng = av_clipl_int32(tgt_eng + (1 << 15)) >> 16;

    if (ccr <= 0)
        return 0;

    /* Compute best energy */
    best_eng = ff_dot_product(buf - index, buf - index,
                              SUBFRAME_LEN * 2)<<1;
    best_eng = av_clipl_int32((int64_t)best_eng + (1 << 15)) >> 16;

    temp = best_eng * *exc_eng >> 3;

    if (temp < ccr * ccr) {
        return index;
    } else
        return 0;
}

/**
 * Peform residual interpolation based on frame classification.
 *
 * @param buf   decoded excitation vector
 * @param out   output vector
 * @param lag   decoded pitch lag
 * @param gain  interpolated gain
 * @param rseed seed for random number generator
 */
static void residual_interp(int16_t *buf, int16_t *out, int lag,
                            int gain, int *rseed)
{
    int i;
    if (lag) { /* Voiced */
        int16_t *vector_ptr = buf + PITCH_MAX;
        /* Attenuate */
        for (i = 0; i < lag; i++)
            vector_ptr[i - lag] = vector_ptr[i - lag] * 3 >> 2;
        av_memcpy_backptr((uint8_t*)vector_ptr, lag * sizeof(int16_t),
                          FRAME_LEN * sizeof(int16_t));
        memcpy(out, vector_ptr, FRAME_LEN * sizeof(int16_t));
    } else {  /* Unvoiced */
        for (i = 0; i < FRAME_LEN; i++) {
            *rseed = *rseed * 521 + 259;
            out[i] = gain * *rseed >> 15;
        }
        memset(buf, 0, (FRAME_LEN + PITCH_MAX) * sizeof(int16_t));
    }
}

/**
 * Perform IIR filtering.
 *
 * @param fir_coef FIR coefficients
 * @param iir_coef IIR coefficients
 * @param src      source vector
 * @param dest     destination vector
 * @param width    width of the output, 16 bits(0) / 32 bits(1)
 */
#define iir_filter(fir_coef, iir_coef, src, dest, width)\
{\
    int m, n;\
    int res_shift = 16 & ~-(width);\
    int in_shift  = 16 - res_shift;\
\
    for (m = 0; m < SUBFRAME_LEN; m++) {\
        int64_t filter = 0;\
        for (n = 1; n <= LPC_ORDER; n++) {\
            filter -= (fir_coef)[n - 1] * (src)[m - n] -\
                      (iir_coef)[n - 1] * ((dest)[m - n] >> in_shift);\
        }\
\
        (dest)[m] = av_clipl_int32(((src)[m] << 16) + (filter << 3) +\
                                   (1 << 15)) >> res_shift;\
    }\
}

/**
 * Adjust gain of postfiltered signal.
 *
 * @param p      the context
 * @param buf    postfiltered output vector
 * @param energy input energy coefficient
 */
static void gain_scale(G723_1_Context *p, int16_t * buf, int energy)
{
    int num, denom, gain, bits1, bits2;
    int i;

    num   = energy;
    denom = 0;
    for (i = 0; i < SUBFRAME_LEN; i++) {
        int64_t temp = buf[i] >> 2;
        temp  = av_clipl_int32(MUL64(temp, temp) << 1);
        denom = av_clipl_int32(denom + temp);
    }

    if (num && denom) {
        bits1   = normalize_bits(num, 1);
        bits2   = normalize_bits(denom, 1);
        num     = num << bits1 >> 1;
        denom <<= bits2;

        bits2 = 5 + bits1 - bits2;
        bits2 = FFMAX(0, bits2);

        gain = (num >> 1) / (denom >> 16);
        gain = square_root(gain << 16 >> bits2);
    } else {
        gain = 1 << 12;
    }

    for (i = 0; i < SUBFRAME_LEN; i++) {
        p->pf_gain = ((p->pf_gain << 4) - p->pf_gain + gain + (1 << 3)) >> 4;
        buf[i]     = av_clip_int16((buf[i] * (p->pf_gain + (p->pf_gain >> 4)) +
                                   (1 << 10)) >> 11);
    }
}

/**
 * Perform formant filtering.
 *
 * @param p   the context
 * @param lpc quantized lpc coefficients
 * @param buf output buffer
 */
static void formant_postfilter(G723_1_Context *p, int16_t *lpc, int16_t *buf)
{
    int16_t filter_coef[2][LPC_ORDER], *buf_ptr;
    int filter_signal[LPC_ORDER + FRAME_LEN], *signal_ptr;
    int i, j, k;

    memcpy(buf, p->fir_mem, LPC_ORDER * sizeof(int16_t));
    memcpy(filter_signal, p->iir_mem, LPC_ORDER * sizeof(int));

    for (i = LPC_ORDER, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++) {
        for (k = 0; k < LPC_ORDER; k++) {
            filter_coef[0][k] = (-lpc[k] * postfilter_tbl[0][k] +
                                 (1 << 14)) >> 15;
            filter_coef[1][k] = (-lpc[k] * postfilter_tbl[1][k] +
                                 (1 << 14)) >> 15;
        }
        iir_filter(filter_coef[0], filter_coef[1], buf + i,
                   filter_signal + i, 1);
    }

    memcpy(p->fir_mem, buf + FRAME_LEN, LPC_ORDER * sizeof(int16_t));
    memcpy(p->iir_mem, filter_signal + FRAME_LEN, LPC_ORDER * sizeof(int));

    buf_ptr    = buf + LPC_ORDER;
    signal_ptr = filter_signal + LPC_ORDER;
    for (i = 0; i < SUBFRAMES; i++) {
        int16_t temp_vector[SUBFRAME_LEN];
        int16_t temp;
        int auto_corr[2];
        int scale, energy;

        /* Normalize */
        memcpy(temp_vector, buf_ptr, SUBFRAME_LEN * sizeof(int16_t));
        scale = scale_vector(temp_vector, SUBFRAME_LEN);

        /* Compute auto correlation coefficients */
        auto_corr[0] = ff_dot_product(temp_vector, temp_vector + 1,
                                      SUBFRAME_LEN - 1)<<1;
        auto_corr[1] = ff_dot_product(temp_vector, temp_vector,
                                      SUBFRAME_LEN)<<1;

        /* Compute reflection coefficient */
        temp = auto_corr[1] >> 16;
        if (temp) {
            temp = (auto_corr[0] >> 2) / temp;
        }
        p->reflection_coef = ((p->reflection_coef << 2) - p->reflection_coef +
                              temp + 2) >> 2;
        temp = (p->reflection_coef * 0xffffc >> 3) & 0xfffc;

        /* Compensation filter */
        for (j = 0; j < SUBFRAME_LEN; j++) {
            buf_ptr[j] = av_clipl_int32(signal_ptr[j] +
                                        ((signal_ptr[j - 1] >> 16) *
                                         temp << 1)) >> 16;
        }

        /* Compute normalized signal energy */
        temp = 2 * scale + 4;
        if (temp < 0) {
            energy = av_clipl_int32((int64_t)auto_corr[1] << -temp);
        } else
            energy = auto_corr[1] >> temp;

        gain_scale(p, buf_ptr, energy);

        buf_ptr    += SUBFRAME_LEN;
        signal_ptr += SUBFRAME_LEN;
    }
}

static int g723_1_decode_frame(AVCodecContext *avctx, void *data,
                               int *data_size, AVPacket *avpkt)
{
    G723_1_Context *p  = avctx->priv_data;
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;
    int16_t *out       = data;
    int dec_mode       = buf[0] & 3;

    PPFParam ppf[SUBFRAMES];
    int16_t cur_lsp[LPC_ORDER];
    int16_t lpc[SUBFRAMES * LPC_ORDER];
    int16_t acb_vector[SUBFRAME_LEN];
    int16_t *vector_ptr;
    int bad_frame = 0, i, j;

    if (!buf_size || buf_size < frame_size[dec_mode]) {
        *data_size = 0;
        return buf_size;
    }

    if (unpack_bitstream(p, buf, buf_size) < 0) {
        bad_frame         = 1;
        p->cur_frame_type = p->past_frame_type == ActiveFrame ?
                            ActiveFrame : UntransmittedFrame;
    }

    *data_size = FRAME_LEN * sizeof(int16_t);
    if(p->cur_frame_type == ActiveFrame) {
        if (!bad_frame) {
            p->erased_frames = 0;
        } else if(p->erased_frames != 3)
            p->erased_frames++;

        inverse_quant(cur_lsp, p->prev_lsp, p->lsp_index, bad_frame);
        lsp_interpolate(lpc, cur_lsp, p->prev_lsp);

        /* Save the lsp_vector for the next frame */
        memcpy(p->prev_lsp, cur_lsp, LPC_ORDER * sizeof(int16_t));

        /* Generate the excitation for the frame */
        memcpy(p->excitation, p->prev_excitation, PITCH_MAX * sizeof(int16_t));
        vector_ptr = p->excitation + PITCH_MAX;
        if (!p->erased_frames) {
            /* Update interpolation gain memory */
            p->interp_gain = fixed_cb_gain[(p->subframe[2].amp_index +
                                            p->subframe[3].amp_index) >> 1];
            for (i = 0; i < SUBFRAMES; i++) {
                gen_fcb_excitation(vector_ptr, p->subframe[i], p->cur_rate,
                                   p->pitch_lag[i >> 1], i);
                gen_acb_excitation(acb_vector, &p->excitation[SUBFRAME_LEN * i],
                                   p->pitch_lag[i >> 1], p->subframe[i],
                                   p->cur_rate);
                /* Get the total excitation */
                for (j = 0; j < SUBFRAME_LEN; j++) {
                    vector_ptr[j] = av_clip_int16(vector_ptr[j] << 1);
                    vector_ptr[j] = av_clip_int16(vector_ptr[j] +
                                                  acb_vector[j]);
                }
                vector_ptr += SUBFRAME_LEN;
            }

            vector_ptr = p->excitation + PITCH_MAX;

            /* Save the excitation */
            memcpy(out, vector_ptr, FRAME_LEN * sizeof(int16_t));

            p->interp_index = comp_interp_index(p, p->pitch_lag[1],
                                                &p->sid_gain, &p->cur_gain);

            for (i = PITCH_MAX, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++)
                comp_ppf_coeff(p, i, p->pitch_lag[j >> 1],
                               ppf + j, p->cur_rate);

            /* Restore the original excitation */
            memcpy(p->excitation, p->prev_excitation,
                   PITCH_MAX * sizeof(int16_t));
            memcpy(vector_ptr, out, FRAME_LEN * sizeof(int16_t));

            /* Peform pitch postfiltering */
            for (i = 0, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++)
                ff_acelp_weighted_vector_sum(out + LPC_ORDER + i, vector_ptr + i,
                                             vector_ptr + i + ppf[j].index,
                                             ppf[j].sc_gain, ppf[j].opt_gain,
                                             1 << 14, 15, SUBFRAME_LEN);
        } else {
            p->interp_gain = (p->interp_gain * 3 + 2) >> 2;
            if (p->erased_frames == 3) {
                /* Mute output */
                memset(p->excitation, 0,
                       (FRAME_LEN + PITCH_MAX) * sizeof(int16_t));
                memset(out, 0, (FRAME_LEN + LPC_ORDER) * sizeof(int16_t));
            } else {
                /* Regenerate frame */
                residual_interp(p->excitation, out + LPC_ORDER, p->interp_index,
                                p->interp_gain, &p->random_seed);
            }
        }
        /* Save the excitation for the next frame */
        memcpy(p->prev_excitation, p->excitation + FRAME_LEN,
               PITCH_MAX * sizeof(int16_t));
    } else {
        memset(out, 0, *data_size);
        av_log(avctx, AV_LOG_WARNING,
               "G.723.1: Comfort noise generation not supported yet\n");
        return frame_size[dec_mode];
    }

    p->past_frame_type = p->cur_frame_type;

    memcpy(out, p->synth_mem, LPC_ORDER * sizeof(int16_t));
    for (i = LPC_ORDER, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++)
        ff_celp_lp_synthesis_filter(out + i, &lpc[j * LPC_ORDER],
                                    out + i, SUBFRAME_LEN, LPC_ORDER,
                                    0, 1, 1 << 12);
    memcpy(p->synth_mem, out + FRAME_LEN, LPC_ORDER * sizeof(int16_t));

    formant_postfilter(p, lpc, out);

    memmove(out, out + LPC_ORDER, *data_size);

    return frame_size[dec_mode];
}

AVCodec ff_g723_1_decoder = {
    .name           = "g723_1",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_G723_1,
    .priv_data_size = sizeof(G723_1_Context),
    .init           = g723_1_decode_init,
    .decode         = g723_1_decode_frame,
    .long_name      = NULL_IF_CONFIG_SMALL("G.723.1"),
    .capabilities   = CODEC_CAP_SUBFRAMES,
};

#if CONFIG_G723_1_ENCODER
#define BITSTREAM_WRITER_LE
#include "put_bits.h"

static av_cold int g723_1_encode_init(AVCodecContext *avctx)
{
    G723_1_Context *p = avctx->priv_data;

    if (avctx->sample_rate != 8000) {
        av_log(avctx, AV_LOG_ERROR, "Only 8000Hz sample rate supported\n");
        return -1;
    }

    if (avctx->channels != 1) {
        av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
        return AVERROR(EINVAL);
    }

    if (avctx->bit_rate == 6300) {
        p->cur_rate = Rate6k3;
    } else if (avctx->bit_rate == 5300) {
        av_log(avctx, AV_LOG_ERROR, "Bitrate not supported yet, use 6.3k\n");
        return AVERROR_PATCHWELCOME;
    } else {
        av_log(avctx, AV_LOG_ERROR,
               "Bitrate not supported, use 6.3k\n");
        return AVERROR(EINVAL);
    }
    avctx->frame_size = 240;
    memcpy(p->prev_lsp, dc_lsp, LPC_ORDER * sizeof(int16_t));

    return 0;
}

/**
 * Remove DC component from the input signal.
 *
 * @param buf input signal
 * @param fir zero memory
 * @param iir pole memory
 */
static void highpass_filter(int16_t *buf, int16_t *fir, int *iir)
{
    int i;
    for (i = 0; i < FRAME_LEN; i++) {
        *iir   = (buf[i] << 15) + ((-*fir) << 15) + MULL2(*iir, 0x7f00);
        *fir   = buf[i];
        buf[i] = av_clipl_int32((int64_t)*iir + (1 << 15)) >> 16;
    }
}

/**
 * Estimate autocorrelation of the input vector.
 *
 * @param buf      input buffer
 * @param autocorr autocorrelation coefficients vector
 */
static void comp_autocorr(int16_t *buf, int16_t *autocorr)
{
    int i, scale, temp;
    int16_t vector[LPC_FRAME];

    memcpy(vector, buf, LPC_FRAME * sizeof(int16_t));
    scale_vector(vector, LPC_FRAME);

    /* Apply the Hamming window */
    for (i = 0; i < LPC_FRAME; i++)
        vector[i] = (vector[i] * hamming_window[i] + (1 << 14)) >> 15;

    /* Compute the first autocorrelation coefficient */
    temp = dot_product(vector, vector, LPC_FRAME, 0);

    /* Apply a white noise correlation factor of (1025/1024) */
    temp += temp >> 10;

    /* Normalize */
    scale = normalize_bits_int32(temp);
    autocorr[0] = av_clipl_int32((int64_t)(temp << scale) +
                                 (1 << 15)) >> 16;

    /* Compute the remaining coefficients */
    if (!autocorr[0]) {
        memset(autocorr + 1, 0, LPC_ORDER * sizeof(int16_t));
    } else {
        for (i = 1; i <= LPC_ORDER; i++) {
           temp = dot_product(vector, vector + i, LPC_FRAME - i, 0);
           temp = MULL2((temp << scale), binomial_window[i - 1]);
           autocorr[i] = av_clipl_int32((int64_t)temp + (1 << 15)) >> 16;
        }
    }
}

/**
 * Use Levinson-Durbin recursion to compute LPC coefficients from
 * autocorrelation values.
 *
 * @param lpc      LPC coefficients vector
 * @param autocorr autocorrelation coefficients vector
 * @param error    prediction error
 */
static void levinson_durbin(int16_t *lpc, int16_t *autocorr, int16_t error)
{
    int16_t vector[LPC_ORDER];
    int16_t partial_corr;
    int i, j, temp;

    memset(lpc, 0, LPC_ORDER * sizeof(int16_t));

    for (i = 0; i < LPC_ORDER; i++) {
        /* Compute the partial correlation coefficient */
        temp = 0;
        for (j = 0; j < i; j++)
            temp -= lpc[j] * autocorr[i - j - 1];
        temp = ((autocorr[i] << 13) + temp) << 3;

        if (FFABS(temp) >= (error << 16))
            break;

        partial_corr = temp / (error << 1);

        lpc[i] = av_clipl_int32((int64_t)(partial_corr << 14) +
                                (1 << 15)) >> 16;

        /* Update the prediction error */
        temp  = MULL2(temp, partial_corr);
        error = av_clipl_int32((int64_t)(error << 16) - temp +
                                (1 << 15)) >> 16;

        memcpy(vector, lpc, i * sizeof(int16_t));
        for (j = 0; j < i; j++) {
            temp = partial_corr * vector[i - j - 1] << 1;
            lpc[j] = av_clipl_int32((int64_t)(lpc[j] << 16) - temp +
                                    (1 << 15)) >> 16;
        }
    }
}

/**
 * Calculate LPC coefficients for the current frame.
 *
 * @param buf       current frame
 * @param prev_data 2 trailing subframes of the previous frame
 * @param lpc       LPC coefficients vector
 */
static void comp_lpc_coeff(int16_t *buf, int16_t *lpc)
{
    int16_t autocorr[(LPC_ORDER + 1) * SUBFRAMES];
    int16_t *autocorr_ptr = autocorr;
    int16_t *lpc_ptr      = lpc;
    int i, j;

    for (i = 0, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++) {
        comp_autocorr(buf + i, autocorr_ptr);
        levinson_durbin(lpc_ptr, autocorr_ptr + 1, autocorr_ptr[0]);

        lpc_ptr += LPC_ORDER;
        autocorr_ptr += LPC_ORDER + 1;
    }
}

static void lpc2lsp(int16_t *lpc, int16_t *prev_lsp, int16_t *lsp)
{
    int f[LPC_ORDER + 2]; ///< coefficients of the sum and difference
                          ///< polynomials (F1, F2) ordered as
                          ///< f1[0], f2[0], ...., f1[5], f2[5]

    int max, shift, cur_val, prev_val, count, p;
    int i, j;
    int64_t temp;

    /* Initialize f1[0] and f2[0] to 1 in Q25 */
    for (i = 0; i < LPC_ORDER; i++)
        lsp[i] = (lpc[i] * bandwidth_expand[i] + (1 << 14)) >> 15;

    /* Apply bandwidth expansion on the LPC coefficients */
    f[0] = f[1] = 1 << 25;

    /* Compute the remaining coefficients */
    for (i = 0; i < LPC_ORDER / 2; i++) {
        /* f1 */
        f[2 * i + 2] = -f[2 * i] - ((lsp[i] + lsp[LPC_ORDER - 1 - i]) << 12);
        /* f2 */
        f[2 * i + 3] = f[2 * i + 1] - ((lsp[i] - lsp[LPC_ORDER - 1 - i]) << 12);
    }

    /* Divide f1[5] and f2[5] by 2 for use in polynomial evaluation */
    f[LPC_ORDER] >>= 1;
    f[LPC_ORDER + 1] >>= 1;

    /* Normalize and shorten */
    max = FFABS(f[0]);
    for (i = 1; i < LPC_ORDER + 2; i++)
        max = FFMAX(max, FFABS(f[i]));

    shift = normalize_bits_int32(max);

    for (i = 0; i < LPC_ORDER + 2; i++)
        f[i] = av_clipl_int32((int64_t)(f[i] << shift) + (1 << 15)) >> 16;

    /**
     * Evaluate F1 and F2 at uniform intervals of pi/256 along the
     * unit circle and check for zero crossings.
     */
    p    = 0;
    temp = 0;
    for (i = 0; i <= LPC_ORDER / 2; i++)
        temp += f[2 * i] * cos_tab[0];
    prev_val = av_clipl_int32(temp << 1);
    count    = 0;
    for ( i = 1; i < COS_TBL_SIZE / 2; i++) {
        /* Evaluate */
        temp = 0;
        for (j = 0; j <= LPC_ORDER / 2; j++)
            temp += f[LPC_ORDER - 2 * j + p] * cos_tab[i * j % COS_TBL_SIZE];
        cur_val = av_clipl_int32(temp << 1);

        /* Check for sign change, indicating a zero crossing */
        if ((cur_val ^ prev_val) < 0) {
            int abs_cur  = FFABS(cur_val);
            int abs_prev = FFABS(prev_val);
            int sum      = abs_cur + abs_prev;

            shift        = normalize_bits_int32(sum);
            sum          <<= shift;
            abs_prev     = abs_prev << shift >> 8;
            lsp[count++] = ((i - 1) << 7) + (abs_prev >> 1) / (sum >> 16);

            if (count == LPC_ORDER)
                break;

            /* Switch between sum and difference polynomials */
            p ^= 1;

            /* Evaluate */
            temp = 0;
            for (j = 0; j <= LPC_ORDER / 2; j++){
                temp += f[LPC_ORDER - 2 * j + p] *
                        cos_tab[i * j % COS_TBL_SIZE];
            }
            cur_val = av_clipl_int32(temp<<1);
        }
        prev_val = cur_val;
    }

    if (count != LPC_ORDER)
        memcpy(lsp, prev_lsp, LPC_ORDER * sizeof(int16_t));
}

/**
 * Quantize the current LSP subvector.
 *
 * @param num    band number
 * @param offset offset of the current subvector in an LPC_ORDER vector
 * @param size   size of the current subvector
 */
#define get_index(num, offset, size) \
{\
    int error, max = -1;\
    int16_t temp[4];\
    int i, j;\
    for (i = 0; i < LSP_CB_SIZE; i++) {\
        for (j = 0; j < size; j++){\
            temp[j] = (weight[j + (offset)] * lsp_band##num[i][j] +\
                      (1 << 14)) >> 15;\
        }\
        error =  dot_product(lsp + (offset), temp, size, 1) << 1;\
        error -= dot_product(lsp_band##num[i], temp, size, 1);\
        if (error > max) {\
            max = error;\
            lsp_index[num] = i;\
        }\
    }\
}

/**
 * Vector quantize the LSP frequencies.
 *
 * @param lsp      the current lsp vector
 * @param prev_lsp the previous lsp vector
 */
static void lsp_quantize(uint8_t *lsp_index, int16_t *lsp, int16_t *prev_lsp)
{
    int16_t weight[LPC_ORDER];
    int16_t min, max;
    int shift, i;

    /* Calculate the VQ weighting vector */
    weight[0] = (1 << 20) / (lsp[1] - lsp[0]);
    weight[LPC_ORDER - 1] = (1 << 20) /
                            (lsp[LPC_ORDER - 1] - lsp[LPC_ORDER - 2]);

    for (i = 1; i < LPC_ORDER - 1; i++) {
        min  = FFMIN(lsp[i] - lsp[i - 1], lsp[i + 1] - lsp[i]);
        if (min > 0x20)
            weight[i] = (1 << 20) / min;
        else
            weight[i] = INT16_MAX;
    }

    /* Normalize */
    max = 0;
    for (i = 0; i < LPC_ORDER; i++)
        max = FFMAX(weight[i], max);

    shift = normalize_bits_int16(max);
    for (i = 0; i < LPC_ORDER; i++) {
        weight[i] <<= shift;
    }

    /* Compute the VQ target vector */
    for (i = 0; i < LPC_ORDER; i++) {
        lsp[i] -= dc_lsp[i] +
                  (((prev_lsp[i] - dc_lsp[i]) * 12288 + (1 << 14)) >> 15);
    }

    get_index(0, 0, 3);
    get_index(1, 3, 3);
    get_index(2, 6, 4);
}

/**
 * Apply the formant perceptual weighting filter.
 *
 * @param flt_coef filter coefficients
 * @param unq_lpc  unquantized lpc vector
 */
static void perceptual_filter(G723_1_Context *p, int16_t *flt_coef,
                              int16_t *unq_lpc, int16_t *buf)
{
    int16_t vector[FRAME_LEN + LPC_ORDER];
    int i, j, k, l = 0;

    memcpy(buf, p->iir_mem, sizeof(int16_t) * LPC_ORDER);
    memcpy(vector, p->fir_mem, sizeof(int16_t) * LPC_ORDER);
    memcpy(vector + LPC_ORDER, buf + LPC_ORDER, sizeof(int16_t) * FRAME_LEN);

    for (i = LPC_ORDER, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++) {
        for (k = 0; k < LPC_ORDER; k++) {
            flt_coef[k + 2 * l] = (unq_lpc[k + l] * percept_flt_tbl[0][k] +
                                  (1 << 14)) >> 15;
            flt_coef[k + 2 * l + LPC_ORDER] = (unq_lpc[k + l] *
                                             percept_flt_tbl[1][k] +
                                             (1 << 14)) >> 15;
        }
        iir_filter(flt_coef + 2 * l, flt_coef + 2 * l + LPC_ORDER, vector + i,
                   buf + i, 0);
        l += LPC_ORDER;
    }
    memcpy(p->iir_mem, buf + FRAME_LEN, sizeof(int16_t) * LPC_ORDER);
    memcpy(p->fir_mem, vector + FRAME_LEN, sizeof(int16_t) * LPC_ORDER);
}

/**
 * Estimate the open loop pitch period.
 *
 * @param buf   perceptually weighted speech
 * @param start estimation is carried out from this position
 */
static int estimate_pitch(int16_t *buf, int start)
{
    int max_exp = 32;
    int max_ccr = 0x4000;
    int max_eng = 0x7fff;
    int index   = PITCH_MIN;
    int offset  = start - PITCH_MIN + 1;

    int ccr, eng, orig_eng, ccr_eng, exp;
    int diff, temp;

    int i;

    orig_eng = dot_product(buf + offset, buf + offset, HALF_FRAME_LEN, 0);

    for (i = PITCH_MIN; i <= PITCH_MAX - 3; i++) {
        offset--;

        /* Update energy and compute correlation */
        orig_eng += buf[offset] * buf[offset] -
                    buf[offset + HALF_FRAME_LEN] * buf[offset + HALF_FRAME_LEN];
        ccr      =  dot_product(buf + start, buf + offset, HALF_FRAME_LEN, 0);
        if (ccr <= 0)
            continue;

        /* Split into mantissa and exponent to maintain precision */
        exp  =   normalize_bits_int32(ccr);
        ccr  =   av_clipl_int32((int64_t)(ccr << exp) + (1 << 15)) >> 16;
        exp  <<= 1;
        ccr  *=  ccr;
        temp =   normalize_bits_int32(ccr);
        ccr  =   ccr << temp >> 16;
        exp  +=  temp;

        temp =   normalize_bits_int32(orig_eng);
        eng  =   av_clipl_int32((int64_t)(orig_eng << temp) + (1 << 15)) >> 16;
        exp  -=  temp;

        if (ccr >= eng) {
            exp--;
            ccr >>= 1;
        }
        if (exp > max_exp)
            continue;

        if (exp + 1 < max_exp)
            goto update;

        /* Equalize exponents before comparison */
        if (exp + 1 == max_exp)
            temp = max_ccr >> 1;
        else
            temp = max_ccr;
        ccr_eng = ccr * max_eng;
        diff    = ccr_eng - eng * temp;
        if (diff > 0 && (i - index < PITCH_MIN || diff > ccr_eng >> 2)) {
update:
            index   = i;
            max_exp = exp;
            max_ccr = ccr;
            max_eng = eng;
        }
    }
    return index;
}

/**
 * Compute harmonic noise filter parameters.
 *
 * @param buf       perceptually weighted speech
 * @param pitch_lag open loop pitch period
 * @param hf        harmonic filter parameters
 */
static void comp_harmonic_coeff(int16_t *buf, int16_t pitch_lag, HFParam *hf)
{
    int ccr, eng, max_ccr, max_eng;
    int exp, max, diff;
    int energy[15];
    int i, j;

    for (i = 0, j = pitch_lag - 3; j <= pitch_lag + 3; i++, j++) {
        /* Compute residual energy */
        energy[i << 1] = dot_product(buf - j, buf - j, SUBFRAME_LEN, 0);
        /* Compute correlation */
        energy[(i << 1) + 1] = dot_product(buf, buf - j, SUBFRAME_LEN, 0);
    }

    /* Compute target energy */
    energy[14] = dot_product(buf, buf, SUBFRAME_LEN, 0);

    /* Normalize */
    max = 0;
    for (i = 0; i < 15; i++)
        max = FFMAX(max, FFABS(energy[i]));

    exp = normalize_bits_int32(max);
    for (i = 0; i < 15; i++) {
        energy[i] = av_clipl_int32((int64_t)(energy[i] << exp) +
                                   (1 << 15)) >> 16;
    }

    hf->index = -1;
    hf->gain  =  0;
    max_ccr   =  1;
    max_eng   =  0x7fff;

    for (i = 0; i <= 6; i++) {
        eng = energy[i << 1];
        ccr = energy[(i << 1) + 1];

        if (ccr <= 0)
            continue;

        ccr  = (ccr * ccr + (1 << 14)) >> 15;
        diff = ccr * max_eng - eng * max_ccr;
        if (diff > 0) {
            max_ccr   = ccr;
            max_eng   = eng;
            hf->index = i;
        }
    }

    if (hf->index == -1) {
        hf->index = pitch_lag;
        return;
    }

    eng = energy[14] * max_eng;
    eng = (eng >> 2) + (eng >> 3);
    ccr = energy[(hf->index << 1) + 1] * energy[(hf->index << 1) + 1];
    if (eng < ccr) {
        eng = energy[(hf->index << 1) + 1];

        if (eng >= max_eng)
            hf->gain = 0x2800;
        else
            hf->gain = ((eng << 15) / max_eng * 0x2800 + (1 << 14)) >> 15;
    }
    hf->index += pitch_lag - 3;
}

/**
 * Apply the harmonic noise shaping filter.
 *
 * @param hf filter parameters
 */
static void harmonic_filter(HFParam *hf, int16_t *src, int16_t *dest)
{
    int i;

    for (i = 0; i < SUBFRAME_LEN; i++) {
        int64_t temp = hf->gain * src[i - hf->index] << 1;
        dest[i] = av_clipl_int32((src[i] << 16) - temp + (1 << 15)) >> 16;
    }
}

static void harmonic_noise_sub(HFParam *hf, int16_t *src, int16_t *dest)
{
    int i;
    for (i = 0; i < SUBFRAME_LEN; i++) {
        int64_t temp = hf->gain * src[i - hf->index] << 1;
        dest[i] = av_clipl_int32(((dest[i] - src[i]) << 16) + temp +
                                 (1 << 15)) >> 16;

    }
}

/**
 * Combined synthesis and formant perceptual weighting filer.
 *
 * @param qnt_lpc  quantized lpc coefficients
 * @param perf_lpc perceptual filter coefficients
 * @param perf_fir perceptual filter fir memory
 * @param perf_iir perceptual filter iir memory
 * @param scale    the filter output will be scaled by 2^scale
 */
static void synth_percept_filter(int16_t *qnt_lpc, int16_t *perf_lpc,
                                 int16_t *perf_fir, int16_t *perf_iir,
                                 int16_t *src, int16_t *dest, int scale)
{
    int i, j;
    int16_t buf_16[SUBFRAME_LEN + LPC_ORDER];
    int64_t buf[SUBFRAME_LEN];

    int16_t *bptr_16 = buf_16 + LPC_ORDER;

    memcpy(buf_16, perf_fir, sizeof(int16_t) * LPC_ORDER);
    memcpy(dest - LPC_ORDER, perf_iir, sizeof(int16_t) * LPC_ORDER);

    for (i = 0; i < SUBFRAME_LEN; i++) {
        int64_t temp = 0;
        for (j = 1; j <= LPC_ORDER; j++)
            temp -= qnt_lpc[j - 1] * bptr_16[i - j];

        buf[i]     = (src[i] << 15) + (temp << 3);
        bptr_16[i] = av_clipl_int32(buf[i] + (1 << 15)) >> 16;
    }

    for (i = 0; i < SUBFRAME_LEN; i++) {
        int64_t fir = 0, iir = 0;
        for (j = 1; j <= LPC_ORDER; j++) {
            fir -= perf_lpc[j - 1] * bptr_16[i - j];
            iir += perf_lpc[j + LPC_ORDER - 1] * dest[i - j];
        }
        dest[i] = av_clipl_int32(((buf[i] + (fir << 3)) << scale) + (iir << 3) +
                                 (1 << 15)) >> 16;
    }
    memcpy(perf_fir, buf_16 + SUBFRAME_LEN, sizeof(int16_t) * LPC_ORDER);
    memcpy(perf_iir, dest + SUBFRAME_LEN - LPC_ORDER,
           sizeof(int16_t) * LPC_ORDER);
}

/**
 * Compute the adaptive codebook contribution.
 *
 * @param buf   input signal
 * @param index the current subframe index
 */
static void acb_search(G723_1_Context *p, int16_t *residual,
                       int16_t *impulse_resp, int16_t *buf,
                       int index)
{

    int16_t flt_buf[PITCH_ORDER][SUBFRAME_LEN];

    const int16_t *cb_tbl = adaptive_cb_gain85;

    int ccr_buf[PITCH_ORDER * SUBFRAMES << 2];

    int pitch_lag = p->pitch_lag[index >> 1];
    int acb_lag   = 1;
    int acb_gain  = 0;
    int odd_frame = index & 1;
    int iter      = 3 + odd_frame;
    int count     = 0;
    int tbl_size  = 85;

    int i, j, k, l, max;
    int64_t temp;

    if (!odd_frame) {
        if (pitch_lag == PITCH_MIN)
            pitch_lag++;
        else
            pitch_lag = FFMIN(pitch_lag, PITCH_MAX - 5);
    }

    for (i = 0; i < iter; i++) {
        get_residual(residual, p->prev_excitation, pitch_lag + i - 1);

        for (j = 0; j < SUBFRAME_LEN; j++) {
            temp = 0;
            for (k = 0; k <= j; k++)
                temp += residual[PITCH_ORDER - 1 + k] * impulse_resp[j - k];
            flt_buf[PITCH_ORDER - 1][j] = av_clipl_int32((temp << 1) +
                                                         (1 << 15)) >> 16;
        }

        for (j = PITCH_ORDER - 2; j >= 0; j--) {
            flt_buf[j][0] = ((residual[j] << 13) + (1 << 14)) >> 15;
            for (k = 1; k < SUBFRAME_LEN; k++) {
                temp = (flt_buf[j + 1][k - 1] << 15) +
                       residual[j] * impulse_resp[k];
                flt_buf[j][k] = av_clipl_int32((temp << 1) + (1 << 15)) >> 16;
            }
        }

        /* Compute crosscorrelation with the signal */
        for (j = 0; j < PITCH_ORDER; j++) {
            temp = dot_product(buf, flt_buf[j], SUBFRAME_LEN, 0);
            ccr_buf[count++] = av_clipl_int32(temp << 1);
        }

        /* Compute energies */
        for (j = 0; j < PITCH_ORDER; j++) {
            ccr_buf[count++] = dot_product(flt_buf[j], flt_buf[j],
                                           SUBFRAME_LEN, 1);
        }

        for (j = 1; j < PITCH_ORDER; j++) {
            for (k = 0; k < j; k++) {
                temp = dot_product(flt_buf[j], flt_buf[k], SUBFRAME_LEN, 0);
                ccr_buf[count++] = av_clipl_int32(temp<<2);
            }
        }
    }

    /* Normalize and shorten */
    max = 0;
    for (i = 0; i < 20 * iter; i++)
        max = FFMAX(max, FFABS(ccr_buf[i]));

    temp = normalize_bits_int32(max);

    for (i = 0; i < 20 * iter; i++){
        ccr_buf[i] = av_clipl_int32((int64_t)(ccr_buf[i] << temp) +
                                    (1 << 15)) >> 16;
    }

    max = 0;
    for (i = 0; i < iter; i++) {
        /* Select quantization table */
        if (!odd_frame && pitch_lag + i - 1 >= SUBFRAME_LEN - 2 ||
            odd_frame && pitch_lag >= SUBFRAME_LEN - 2) {
            cb_tbl = adaptive_cb_gain170;
            tbl_size = 170;
        }

        for (j = 0, k = 0; j < tbl_size; j++, k += 20) {
            temp = 0;
            for (l = 0; l < 20; l++)
                temp += ccr_buf[20 * i + l] * cb_tbl[k + l];
            temp =  av_clipl_int32(temp);

            if (temp > max) {
                max      = temp;
                acb_gain = j;
                acb_lag  = i;
            }
        }
    }

    if (!odd_frame) {
        pitch_lag += acb_lag - 1;
        acb_lag   =  1;
    }

    p->pitch_lag[index >> 1]      = pitch_lag;
    p->subframe[index].ad_cb_lag  = acb_lag;
    p->subframe[index].ad_cb_gain = acb_gain;
}

/**
 * Subtract the adaptive codebook contribution from the input
 * to obtain the residual.
 *
 * @param buf target vector
 */
static void sub_acb_contrib(int16_t *residual, int16_t *impulse_resp,
                            int16_t *buf)
{
    int i, j;
    /* Subtract adaptive CB contribution to obtain the residual */
    for (i = 0; i < SUBFRAME_LEN; i++) {
        int64_t temp = buf[i] << 14;
        for (j = 0; j <= i; j++)
            temp -= residual[j] * impulse_resp[i - j];

        buf[i] = av_clipl_int32((temp << 2) + (1 << 15)) >> 16;
    }
}

/**
 * Quantize the residual signal using the fixed codebook (MP-MLQ).
 *
 * @param optim optimized fixed codebook parameters
 * @param buf   excitation vector
 */
static void get_fcb_param(FCBParam *optim, int16_t *impulse_resp,
                          int16_t *buf, int pulse_cnt, int pitch_lag)
{
    FCBParam param;
    int16_t impulse_r[SUBFRAME_LEN];
    int16_t temp_corr[SUBFRAME_LEN];
    int16_t impulse_corr[SUBFRAME_LEN];

    int ccr1[SUBFRAME_LEN];
    int ccr2[SUBFRAME_LEN];
    int amp, err, max, max_amp_index, min, scale, i, j, k, l;

    int64_t temp;

    /* Update impulse response */
    memcpy(impulse_r, impulse_resp, sizeof(int16_t) * SUBFRAME_LEN);
    param.dirac_train = 0;
    if (pitch_lag < SUBFRAME_LEN - 2) {
        param.dirac_train = 1;
        gen_dirac_train(impulse_r, pitch_lag);
    }

    for (i = 0; i < SUBFRAME_LEN; i++)
        temp_corr[i] = impulse_r[i] >> 1;

    /* Compute impulse response autocorrelation */
    temp = dot_product(temp_corr, temp_corr, SUBFRAME_LEN, 1);

    scale = normalize_bits_int32(temp);
    impulse_corr[0] = av_clipl_int32((temp << scale) + (1 << 15)) >> 16;

    for (i = 1; i < SUBFRAME_LEN; i++) {
        temp = dot_product(temp_corr + i, temp_corr, SUBFRAME_LEN - i, 1);
        impulse_corr[i] = av_clipl_int32((temp << scale) + (1 << 15)) >> 16;
    }

    /* Compute crosscorrelation of impulse response with residual signal */
    scale -= 4;
    for (i = 0; i < SUBFRAME_LEN; i++){
        temp = dot_product(buf + i, impulse_r, SUBFRAME_LEN - i, 1);
        if (scale < 0)
            ccr1[i] = temp >> -scale;
        else
            ccr1[i] = av_clipl_int32(temp << scale);
    }

    /* Search loop */
    for (i = 0; i < GRID_SIZE; i++) {
        /* Maximize the crosscorrelation */
        max = 0;
        for (j = i; j < SUBFRAME_LEN; j += GRID_SIZE) {
            temp = FFABS(ccr1[j]);
            if (temp >= max) {
                max = temp;
                param.pulse_pos[0] = j;
            }
        }

        /* Quantize the gain (max crosscorrelation/impulse_corr[0]) */
        amp = max;
        min = 1 << 30;
        max_amp_index = GAIN_LEVELS - 2;
        for (j = max_amp_index; j >= 2; j--) {
            temp = av_clipl_int32((int64_t)fixed_cb_gain[j] *
                                  impulse_corr[0] << 1);
            temp = FFABS(temp - amp);
            if (temp < min) {
                min = temp;
                max_amp_index = j;
            }
        }

        max_amp_index--;
        /* Select additional gain values */
        for (j = 1; j < 5; j++) {
            for (k = i; k < SUBFRAME_LEN; k += GRID_SIZE) {
                temp_corr[k] = 0;
                ccr2[k]      = ccr1[k];
            }
            param.amp_index = max_amp_index + j - 2;
            amp = fixed_cb_gain[param.amp_index];

            param.pulse_sign[0] = (ccr2[param.pulse_pos[0]] < 0) ? -amp : amp;
            temp_corr[param.pulse_pos[0]] = 1;

            for (k = 1; k < pulse_cnt; k++) {
                max = -1 << 30;
                for (l = i; l < SUBFRAME_LEN; l += GRID_SIZE) {
                    if (temp_corr[l])
                        continue;
                    temp = impulse_corr[FFABS(l - param.pulse_pos[k - 1])];
                    temp = av_clipl_int32((int64_t)temp *
                                          param.pulse_sign[k - 1] << 1);
                    ccr2[l] -= temp;
                    temp = FFABS(ccr2[l]);
                    if (temp > max) {
                        max = temp;
                        param.pulse_pos[k] = l;
                    }
                }

                param.pulse_sign[k] = (ccr2[param.pulse_pos[k]] < 0) ?
                                      -amp : amp;
                temp_corr[param.pulse_pos[k]] = 1;
            }

            /* Create the error vector */
            memset(temp_corr, 0, sizeof(int16_t) * SUBFRAME_LEN);

            for (k = 0; k < pulse_cnt; k++)
                temp_corr[param.pulse_pos[k]] = param.pulse_sign[k];

            for (k = SUBFRAME_LEN - 1; k >= 0; k--) {
                temp = 0;
                for (l = 0; l <= k; l++) {
                    int prod = av_clipl_int32((int64_t)temp_corr[l] *
                                              impulse_r[k - l] << 1);
                    temp     = av_clipl_int32(temp + prod);
                }
                temp_corr[k] = temp << 2 >> 16;
            }

            /* Compute square of error */
            err = 0;
            for (k = 0; k < SUBFRAME_LEN; k++) {
                int64_t prod;
                prod = av_clipl_int32((int64_t)buf[k] * temp_corr[k] << 1);
                err  = av_clipl_int32(err - prod);
                prod = av_clipl_int32((int64_t)temp_corr[k] * temp_corr[k]);
                err  = av_clipl_int32(err + prod);
            }

            /* Minimize */
            if (err < optim->min_err) {
                optim->min_err     = err;
                optim->grid_index  = i;
                optim->amp_index   = param.amp_index;
                optim->dirac_train = param.dirac_train;

                for (k = 0; k < pulse_cnt; k++) {
                    optim->pulse_sign[k] = param.pulse_sign[k];
                    optim->pulse_pos[k]  = param.pulse_pos[k];
                }
            }
        }
    }
}

/**
 * Encode the pulse position and gain of the current subframe.
 *
 * @param optim optimized fixed CB parameters
 * @param buf   excitation vector
 */
static void pack_fcb_param(G723_1_Subframe *subfrm, FCBParam *optim,
                           int16_t *buf, int pulse_cnt)
{
    int i, j;

    j = PULSE_MAX - pulse_cnt;

    subfrm->pulse_sign = 0;
    subfrm->pulse_pos  = 0;

    for (i = 0; i < SUBFRAME_LEN >> 1; i++) {
        int val = buf[optim->grid_index + (i << 1)];
        if (!val) {
            subfrm->pulse_pos += combinatorial_table[j][i];
        } else {
            subfrm->pulse_sign <<= 1;
            if (val < 0) subfrm->pulse_sign++;
            j++;

            if (j == PULSE_MAX) break;
        }
    }
    subfrm->amp_index   = optim->amp_index;
    subfrm->grid_index  = optim->grid_index;
    subfrm->dirac_train = optim->dirac_train;
}

/**
 * Compute the fixed codebook excitation.
 *
 * @param buf          target vector
 * @param impulse_resp impulse response of the combined filter
 */
static void fcb_search(G723_1_Context *p, int16_t *impulse_resp,
                       int16_t *buf, int index)
{
    FCBParam optim;
    int pulse_cnt = pulses[index];
    int i;

    optim.min_err = 1 << 30;
    get_fcb_param(&optim, impulse_resp, buf, pulse_cnt, SUBFRAME_LEN);

    if (p->pitch_lag[index >> 1] < SUBFRAME_LEN - 2) {
        get_fcb_param(&optim, impulse_resp, buf, pulse_cnt,
                      p->pitch_lag[index >> 1]);
    }

    /* Reconstruct the excitation */
    memset(buf, 0, sizeof(int16_t) * SUBFRAME_LEN);
    for (i = 0; i < pulse_cnt; i++)
        buf[optim.pulse_pos[i]] = optim.pulse_sign[i];

    pack_fcb_param(&p->subframe[index], &optim, buf, pulse_cnt);

    if (optim.dirac_train)
        gen_dirac_train(buf, p->pitch_lag[index >> 1]);
}

/**
 * Pack the frame parameters into output bitstream.
 *
 * @param frame output buffer
 * @param size  size of the buffer
 */
static int pack_bitstream(G723_1_Context *p, unsigned char *frame, int size)
{
    PutBitContext pb;
    int info_bits, i, temp;

    init_put_bits(&pb, frame, size);

    if (p->cur_rate == Rate6k3) {
        info_bits = 0;
        put_bits(&pb, 2, info_bits);
    }

    put_bits(&pb, 8, p->lsp_index[2]);
    put_bits(&pb, 8, p->lsp_index[1]);
    put_bits(&pb, 8, p->lsp_index[0]);

    put_bits(&pb, 7, p->pitch_lag[0] - PITCH_MIN);
    put_bits(&pb, 2, p->subframe[1].ad_cb_lag);
    put_bits(&pb, 7, p->pitch_lag[1] - PITCH_MIN);
    put_bits(&pb, 2, p->subframe[3].ad_cb_lag);

    /* Write 12 bit combined gain */
    for (i = 0; i < SUBFRAMES; i++) {
        temp = p->subframe[i].ad_cb_gain * GAIN_LEVELS +
               p->subframe[i].amp_index;
        if (p->cur_rate ==  Rate6k3)
            temp += p->subframe[i].dirac_train << 11;
        put_bits(&pb, 12, temp);
    }

    put_bits(&pb, 1, p->subframe[0].grid_index);
    put_bits(&pb, 1, p->subframe[1].grid_index);
    put_bits(&pb, 1, p->subframe[2].grid_index);
    put_bits(&pb, 1, p->subframe[3].grid_index);

    if (p->cur_rate == Rate6k3) {
        skip_put_bits(&pb, 1); /* reserved bit */

        /* Write 13 bit combined position index */
        temp = (p->subframe[0].pulse_pos >> 16) * 810 +
               (p->subframe[1].pulse_pos >> 14) *  90 +
               (p->subframe[2].pulse_pos >> 16) *   9 +
               (p->subframe[3].pulse_pos >> 14);
        put_bits(&pb, 13, temp);

        put_bits(&pb, 16, p->subframe[0].pulse_pos & 0xffff);
        put_bits(&pb, 14, p->subframe[1].pulse_pos & 0x3fff);
        put_bits(&pb, 16, p->subframe[2].pulse_pos & 0xffff);
        put_bits(&pb, 14, p->subframe[3].pulse_pos & 0x3fff);

        put_bits(&pb, 6, p->subframe[0].pulse_sign);
        put_bits(&pb, 5, p->subframe[1].pulse_sign);
        put_bits(&pb, 6, p->subframe[2].pulse_sign);
        put_bits(&pb, 5, p->subframe[3].pulse_sign);
    }

    flush_put_bits(&pb);
    return frame_size[info_bits];
}

static int g723_1_encode_frame(AVCodecContext *avctx, unsigned char *buf,
                               int buf_size, void *data)
{
    G723_1_Context *p = avctx->priv_data;
    int16_t unq_lpc[LPC_ORDER * SUBFRAMES];
    int16_t qnt_lpc[LPC_ORDER * SUBFRAMES];
    int16_t cur_lsp[LPC_ORDER];
    int16_t weighted_lpc[LPC_ORDER * SUBFRAMES << 1];
    int16_t vector[FRAME_LEN + PITCH_MAX];
    int offset;
    int16_t *in = data;

    HFParam hf[4];
    int i, j;

    highpass_filter(in, &p->hpf_fir_mem, &p->hpf_iir_mem);

    memcpy(vector, p->prev_data, HALF_FRAME_LEN * sizeof(int16_t));
    memcpy(vector + HALF_FRAME_LEN, in, FRAME_LEN * sizeof(int16_t));

    comp_lpc_coeff(vector, unq_lpc);
    lpc2lsp(&unq_lpc[LPC_ORDER * 3], p->prev_lsp, cur_lsp);
    lsp_quantize(p->lsp_index, cur_lsp, p->prev_lsp);

    /* Update memory */
    memcpy(vector + LPC_ORDER, p->prev_data + SUBFRAME_LEN,
           sizeof(int16_t) * SUBFRAME_LEN);
    memcpy(vector + LPC_ORDER + SUBFRAME_LEN, in,
           sizeof(int16_t) * (HALF_FRAME_LEN + SUBFRAME_LEN));
    memcpy(p->prev_data, in + HALF_FRAME_LEN,
           sizeof(int16_t) * HALF_FRAME_LEN);
    memcpy(in, vector + LPC_ORDER, sizeof(int16_t) * FRAME_LEN);

    perceptual_filter(p, weighted_lpc, unq_lpc, vector);

    memcpy(in, vector + LPC_ORDER, sizeof(int16_t) * FRAME_LEN);
    memcpy(vector, p->prev_weight_sig, sizeof(int16_t) * PITCH_MAX);
    memcpy(vector + PITCH_MAX, in, sizeof(int16_t) * FRAME_LEN);

    scale_vector(vector, FRAME_LEN + PITCH_MAX);

    p->pitch_lag[0] = estimate_pitch(vector, PITCH_MAX);
    p->pitch_lag[1] = estimate_pitch(vector, PITCH_MAX + HALF_FRAME_LEN);

    for (i = PITCH_MAX, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++)
        comp_harmonic_coeff(vector + i, p->pitch_lag[j >> 1], hf + j);

    memcpy(vector, p->prev_weight_sig, sizeof(int16_t) * PITCH_MAX);
    memcpy(vector + PITCH_MAX, in, sizeof(int16_t) * FRAME_LEN);
    memcpy(p->prev_weight_sig, vector + FRAME_LEN, sizeof(int16_t) * PITCH_MAX);

    for (i = 0, j = 0; j < SUBFRAMES; i += SUBFRAME_LEN, j++)
        harmonic_filter(hf + j, vector + PITCH_MAX + i, in + i);

    inverse_quant(cur_lsp, p->prev_lsp, p->lsp_index, 0);
    lsp_interpolate(qnt_lpc, cur_lsp, p->prev_lsp);

    memcpy(p->prev_lsp, cur_lsp, sizeof(int16_t) * LPC_ORDER);

    offset = 0;
    for (i = 0; i < SUBFRAMES; i++) {
        int16_t impulse_resp[SUBFRAME_LEN];
        int16_t residual[SUBFRAME_LEN + PITCH_ORDER - 1];
        int16_t flt_in[SUBFRAME_LEN];
        int16_t zero[LPC_ORDER], fir[LPC_ORDER], iir[LPC_ORDER];

        /**
         * Compute the combined impulse response of the synthesis filter,
         * formant perceptual weighting filter and harmonic noise shaping filter
         */
        memset(zero, 0, sizeof(int16_t) * LPC_ORDER);
        memset(vector, 0, sizeof(int16_t) * PITCH_MAX);
        memset(flt_in, 0, sizeof(int16_t) * SUBFRAME_LEN);

        flt_in[0] = 1 << 13; /* Unit impulse */
        synth_percept_filter(qnt_lpc + offset, weighted_lpc + (offset << 1),
                             zero, zero, flt_in, vector + PITCH_MAX, 1);
        harmonic_filter(hf + i, vector + PITCH_MAX, impulse_resp);

         /* Compute the combined zero input response */
        flt_in[0] = 0;
        memcpy(fir, p->perf_fir_mem, sizeof(int16_t) * LPC_ORDER);
        memcpy(iir, p->perf_iir_mem, sizeof(int16_t) * LPC_ORDER);

        synth_percept_filter(qnt_lpc + offset, weighted_lpc + (offset << 1),
                             fir, iir, flt_in, vector + PITCH_MAX, 0);
        memcpy(vector, p->harmonic_mem, sizeof(int16_t) * PITCH_MAX);
        harmonic_noise_sub(hf + i, vector + PITCH_MAX, in);

        acb_search(p, residual, impulse_resp, in, i);
        gen_acb_excitation(residual, p->prev_excitation,p->pitch_lag[i >> 1],
                           p->subframe[i], p->cur_rate);
        sub_acb_contrib(residual, impulse_resp, in);

        fcb_search(p, impulse_resp, in, i);

        /* Reconstruct the excitation */
        gen_acb_excitation(impulse_resp, p->prev_excitation, p->pitch_lag[i >> 1],
                           p->subframe[i], Rate6k3);

        memmove(p->prev_excitation, p->prev_excitation + SUBFRAME_LEN,
               sizeof(int16_t) * (PITCH_MAX - SUBFRAME_LEN));
        for (j = 0; j < SUBFRAME_LEN; j++)
            in[j] = av_clip_int16((in[j] << 1) + impulse_resp[j]);
        memcpy(p->prev_excitation + PITCH_MAX - SUBFRAME_LEN, in,
               sizeof(int16_t) * SUBFRAME_LEN);

        /* Update filter memories */
        synth_percept_filter(qnt_lpc + offset, weighted_lpc + (offset << 1),
                             p->perf_fir_mem, p->perf_iir_mem,
                             in, vector + PITCH_MAX, 0);
        memmove(p->harmonic_mem, p->harmonic_mem + SUBFRAME_LEN,
                sizeof(int16_t) * (PITCH_MAX - SUBFRAME_LEN));
        memcpy(p->harmonic_mem + PITCH_MAX - SUBFRAME_LEN, vector + PITCH_MAX,
               sizeof(int16_t) * SUBFRAME_LEN);

        in += SUBFRAME_LEN;
        offset += LPC_ORDER;
    }

    return pack_bitstream(p, buf, buf_size);
}

AVCodec ff_g723_1_encoder = {
    .name           = "g723_1",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_G723_1,
    .priv_data_size = sizeof(G723_1_Context),
    .init           = g723_1_encode_init,
    .encode         = g723_1_encode_frame,
    .long_name      = NULL_IF_CONFIG_SMALL("G.723.1"),
    .sample_fmts    = (const enum SampleFormat[]){SAMPLE_FMT_S16,
                                                  SAMPLE_FMT_NONE},
};
#endif