avcodec: add native iLBC decoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 1487 insertions, 0 deletions

diff --git a/libavcodec/ilbcdec.c b/libavcodec/ilbcdec.c
new file mode 100644
index 0000000000..7f015d90f2
--- /dev/null
+++ b/libavcodec/ilbcdec.c
@@ -0,0 +1,1487 @@
+/*
+ * Copyright (c) 2013, The WebRTC project authors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of Google nor the names of its contributors may
+ *     be used to endorse or promote products derived from this software
+ *     without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "avcodec.h"
+#include "internal.h"
+#include "get_bits.h"
+#include "ilbcdata.h"
+
+#define LPC_N_20MS            1
+#define LPC_N_30MS            2
+#define LPC_N_MAX             2
+#define LSF_NSPLIT            3
+#define NASUB_MAX             4
+#define LPC_FILTERORDER       10
+#define NSUB_MAX              6
+#define SUBL                  40
+
+#define ST_MEM_L_TBL          85
+#define MEM_LF_TBL            147
+#define STATE_SHORT_LEN_20MS  57
+#define STATE_SHORT_LEN_30MS  58
+
+#define BLOCKL_MAX            240
+#define CB_MEML               147
+#define CB_NSTAGES            3
+#define CB_HALFFILTERLEN      4
+#define CB_FILTERLEN          8
+
+#define ENH_NBLOCKS_TOT 8
+#define ENH_BLOCKL     80
+#define ENH_BUFL     (ENH_NBLOCKS_TOT)*ENH_BLOCKL
+#define ENH_BUFL_FILTEROVERHEAD  3
+#define BLOCKL_MAX      240
+#define NSUB_20MS         4
+#define NSUB_30MS         6
+#define NSUB_MAX          6
+#define NASUB_20MS        2
+#define NASUB_30MS        4
+#define NASUB_MAX         4
+#define STATE_LEN        80
+#define STATE_SHORT_LEN_30MS  58
+#define STATE_SHORT_LEN_20MS  57
+
+#define SPL_MUL_16_16(a, b) ((int32_t) (((int16_t)(a)) * ((int16_t)(b))))
+#define SPL_MUL_16_16_RSFT(a, b, c) (SPL_MUL_16_16(a, b) >> (c))
+
+typedef struct ILBCFrame {
+    int16_t  lsf[LSF_NSPLIT*LPC_N_MAX];
+    int16_t  cb_index[CB_NSTAGES*(NASUB_MAX + 1)];
+    int16_t  gain_index[CB_NSTAGES*(NASUB_MAX + 1)];
+    int16_t  ifm;
+    int16_t  state_first;
+    int16_t  idx[STATE_SHORT_LEN_30MS];
+    int16_t  firstbits;
+    int16_t  start;
+} ILBCFrame;
+
+typedef struct ILBCContext {
+    AVClass         *class;
+    int              enhancer;
+
+    int              mode;
+    GetBitContext    gb;
+    ILBCFrame        frame;
+
+    int              prev_enh_pl;
+    int              consPLICount;
+    int              last_lag;
+    int              state_short_len;
+    int              lpc_n;
+    int16_t          nasub;
+    int16_t          nsub;
+    int              block_samples;
+    int16_t          no_of_words;
+    int16_t          no_of_bytes;
+    int16_t          lsfdeq[LPC_FILTERORDER*LPC_N_MAX];
+    int16_t          lsfold[LPC_FILTERORDER];
+    int16_t          syntMem[LPC_FILTERORDER];
+    int16_t          lsfdeqold[LPC_FILTERORDER];
+    int16_t          weightdenum[(LPC_FILTERORDER + 1) * NSUB_MAX];
+    int16_t          syntdenum[NSUB_MAX * (LPC_FILTERORDER + 1)];
+    int16_t          old_syntdenum[NSUB_MAX * (LPC_FILTERORDER + 1)];
+    int16_t          enh_buf[ENH_BUFL+ENH_BUFL_FILTEROVERHEAD];
+    int16_t          enh_period[ENH_NBLOCKS_TOT];
+    int16_t          prevResidual[NSUB_MAX*SUBL];
+    int16_t          decresidual[BLOCKL_MAX];
+    int16_t          plc_residual[BLOCKL_MAX + LPC_FILTERORDER];
+    int16_t          seed;
+    int16_t          prevPLI;
+    int16_t          prevScale;
+    int16_t          prevLag;
+    int16_t          per_square;
+    int16_t          prev_lpc[LPC_FILTERORDER + 1];
+    int16_t          plc_lpc[LPC_FILTERORDER + 1];
+    int16_t          hpimemx[2];
+    int16_t          hpimemy[4];
+} ILBCContext;
+
+static int unpack_frame(ILBCContext *s)
+{
+    ILBCFrame *frame = &s->frame;
+    GetBitContext *gb = &s->gb;
+    int j;
+
+    frame->lsf[0] = get_bits(gb, 6);
+    frame->lsf[1] = get_bits(gb, 7);
+    frame->lsf[2] = get_bits(gb, 7);
+
+    if (s->mode = 20) {
+        frame->start          = get_bits(gb, 2);
+        frame->state_first    = get_bits1(gb);
+        frame->ifm            = get_bits(gb, 6);
+        frame->cb_index[0]    = get_bits(gb, 6) << 1;
+        frame->gain_index[0]  = get_bits(gb, 2) << 3;
+        frame->gain_index[1]  = get_bits1(gb) << 3;
+        frame->cb_index[3]    = get_bits(gb, 7) << 1;
+        frame->gain_index[3]  = get_bits1(gb) << 4;
+        frame->gain_index[4]  = get_bits1(gb) << 3;
+        frame->gain_index[6]  = get_bits1(gb) << 4;
+    } else {
+        frame->lsf[3]         = get_bits(gb, 6);
+        frame->lsf[4]         = get_bits(gb, 7);
+        frame->lsf[5]         = get_bits(gb, 7);
+        frame->start          = get_bits(gb, 3);
+        frame->state_first    = get_bits1(gb);
+        frame->ifm            = get_bits(gb, 6);
+        frame->cb_index[0]    = get_bits(gb, 4) << 3;
+        frame->gain_index[0]  = get_bits1(gb) << 4;
+        frame->gain_index[1]  = get_bits1(gb) << 3;
+        frame->cb_index[3]    = get_bits(gb, 6) << 2;
+        frame->gain_index[3]  = get_bits1(gb) << 4;
+        frame->gain_index[4]  = get_bits1(gb) << 3;
+    }
+
+    for (j = 0; j < 48; j++)
+        frame->idx[j] = get_bits1(gb) << 2;
+
+    if (s->mode == 20) {
+        for (; j < 57; j++)
+            frame->idx[j] = get_bits1(gb) << 2;
+
+        frame->gain_index[1] |= get_bits1(gb) << 2;
+        frame->gain_index[3] |= get_bits(gb, 2) << 2;
+        frame->gain_index[4] |= get_bits1(gb) << 2;
+        frame->gain_index[6] |= get_bits1(gb) << 3;
+        frame->gain_index[7]  = get_bits(gb, 2) << 2;
+    } else {
+        for (; j < 58; j++)
+            frame->idx[j] = get_bits1(gb) << 2;
+
+        frame->cb_index[0]    |= get_bits(gb, 2) << 1;
+        frame->gain_index[0]  |= get_bits1(gb) << 3;
+        frame->gain_index[1]  |= get_bits1(gb) << 2;
+        frame->cb_index[3]    |= get_bits1(gb) << 1;
+        frame->cb_index[6]     = get_bits1(gb) << 7;
+        frame->cb_index[6]    |= get_bits(gb, 6) << 1;
+        frame->cb_index[9]     = get_bits(gb, 7) << 1;
+        frame->cb_index[12]    = get_bits(gb, 3) << 5;
+        frame->cb_index[12]   |= get_bits(gb, 4) << 1;
+        frame->gain_index[3]  |= get_bits(gb, 2) << 2;
+        frame->gain_index[4]  |= get_bits(gb, 2) << 1;
+        frame->gain_index[6]   = get_bits(gb, 2) << 3;
+        frame->gain_index[7]   = get_bits(gb, 2) << 2;
+        frame->gain_index[9]   = get_bits1(gb) << 4;
+        frame->gain_index[10]  = get_bits1(gb) << 3;
+        frame->gain_index[12]  = get_bits1(gb) << 4;
+        frame->gain_index[13]  = get_bits1(gb) << 3;
+    }
+
+    for (j = 0; j < 56; j++)
+        frame->idx[j] |= get_bits(gb, 2);
+
+    if (s->mode == 20) {
+        frame->idx[56]        |= get_bits(gb, 2);
+        frame->cb_index[0]    |= get_bits1(gb);
+        frame->cb_index[1]     = get_bits(gb, 7);
+        frame->cb_index[2]     = get_bits(gb, 6) << 1;
+        frame->cb_index[2]    |= get_bits1(gb);
+        frame->gain_index[0]  |= get_bits(gb, 3);
+        frame->gain_index[1]  |= get_bits(gb, 2);
+        frame->gain_index[2]   = get_bits(gb, 3);
+        frame->cb_index[3]    |= get_bits1(gb);
+        frame->cb_index[4]     = get_bits(gb, 6) << 1;
+        frame->cb_index[4]    |= get_bits1(gb);
+        frame->cb_index[5]     = get_bits(gb, 7);
+        frame->cb_index[6]     = get_bits(gb, 8);
+        frame->cb_index[7]     = get_bits(gb, 8);
+        frame->cb_index[8]     = get_bits(gb, 8);
+        frame->gain_index[3]  |= get_bits(gb, 2);
+        frame->gain_index[4]  |= get_bits(gb, 2);
+        frame->gain_index[5]   = get_bits(gb, 3);
+        frame->gain_index[6]  |= get_bits(gb, 3);
+        frame->gain_index[7]  |= get_bits(gb, 2);
+        frame->gain_index[8]   = get_bits(gb, 3);
+    } else {
+        frame->idx[56]        |= get_bits(gb, 2);
+        frame->idx[57]        |= get_bits(gb, 2);
+        frame->cb_index[0]    |= get_bits1(gb);
+        frame->cb_index[1]     = get_bits(gb, 7);
+        frame->cb_index[2]     = get_bits(gb, 4) << 3;
+        frame->cb_index[2]    |= get_bits(gb, 3);
+        frame->gain_index[0]  |= get_bits(gb, 3);
+        frame->gain_index[1]  |= get_bits(gb, 2);
+        frame->gain_index[2]   = get_bits(gb, 3);
+        frame->cb_index[3]    |= get_bits1(gb);
+        frame->cb_index[4]     = get_bits(gb, 4) << 3;
+        frame->cb_index[4]    |= get_bits(gb, 3);
+        frame->cb_index[5]     = get_bits(gb, 7);
+        frame->cb_index[6]    |= get_bits1(gb);
+        frame->cb_index[7]     = get_bits(gb, 5) << 3;
+        frame->cb_index[7]    |= get_bits(gb, 3);
+        frame->cb_index[8]     = get_bits(gb, 8);
+        frame->cb_index[9]    |= get_bits1(gb);
+        frame->cb_index[10]    = get_bits(gb, 4) << 4;
+        frame->cb_index[10]   |= get_bits(gb, 4);
+        frame->cb_index[11]    = get_bits(gb, 8);
+        frame->cb_index[12]   |= get_bits1(gb);
+        frame->cb_index[13]    = get_bits(gb, 3) << 5;
+        frame->cb_index[13]   |= get_bits(gb, 5);
+        frame->cb_index[14]    = get_bits(gb, 8);
+        frame->gain_index[3]  |= get_bits(gb, 2);
+        frame->gain_index[4]  |= get_bits1(gb);
+        frame->gain_index[5]   = get_bits(gb, 3);
+        frame->gain_index[6]  |= get_bits(gb, 3);
+        frame->gain_index[7]  |= get_bits(gb, 2);
+        frame->gain_index[8]   = get_bits(gb, 3);
+        frame->gain_index[9]  |= get_bits(gb, 4);
+        frame->gain_index[10] |= get_bits1(gb) << 2;
+        frame->gain_index[10] |= get_bits(gb, 2);
+        frame->gain_index[11]  = get_bits(gb, 3);
+        frame->gain_index[12] |= get_bits(gb, 4);
+        frame->gain_index[13] |= get_bits(gb, 3);
+        frame->gain_index[14]  = get_bits(gb, 3);
+    }
+
+    return get_bits1(gb);
+}
+
+static void index_conv(int16_t *index)
+{
+    int k;
+
+    for (k = 4; k < 6; k++) {
+        if (index[k] >= 44 && index[k] < 108) {
+            index[k] += 64;
+        } else if (index[k] >= 108 && index[k] < 128) {
+            index[k] += 128;
+        }
+    }
+}
+
+static void lsf_dequantization(int16_t *lsfdeq, int16_t *index, int16_t lpc_n)
+{
+    int i, j, pos = 0, cb_pos = 0;
+
+    for (i = 0; i < LSF_NSPLIT; i++) {
+        for (j = 0; j < lsf_dim_codebook[i]; j++) {
+            lsfdeq[pos + j] = lsf_codebook[cb_pos + index[i] * lsf_dim_codebook[i] + j];
+        }
+
+        pos    += lsf_dim_codebook[i];
+        cb_pos += lsf_size_codebook[i] * lsf_dim_codebook[i];
+    }
+
+    if (lpc_n > 1) {
+        pos = 0;
+        cb_pos = 0;
+        for (i = 0; i < LSF_NSPLIT; i++) {
+            for (j = 0; j < lsf_dim_codebook[i]; j++) {
+                lsfdeq[LPC_FILTERORDER + pos + j] = lsf_codebook[cb_pos +
+                    index[LSF_NSPLIT + i] * lsf_dim_codebook[i] + j];
+            }
+
+            pos    += lsf_dim_codebook[i];
+            cb_pos += lsf_size_codebook[i] * lsf_dim_codebook[i];
+        }
+    }
+}
+
+static void lsf_check_stability(int16_t *lsf, int dim, int nb_vectors)
+{
+    for (int n = 0; n < 2; n++) {
+        for (int m = 0; m < nb_vectors; m++) {
+            for (int k = 0; k < dim - 1; k++) {
+                int i = m * dim + k;
+
+                if ((lsf[i + 1] - lsf[i]) < 319) {
+                    if (lsf[i + 1] < lsf[i]) {
+                        lsf[i + 1] = lsf[i] + 160;
+                        lsf[i]     = lsf[i + 1] - 160;
+                    } else {
+                        lsf[i]     -= 160;
+                        lsf[i + 1] += 160;
+                    }
+                }
+
+                lsf[i] = av_clip(lsf[i], 82, 25723);
+            }
+        }
+    }
+}
+
+static void lsf_interpolate(int16_t *out, int16_t *in1,
+                            int16_t *in2, int16_t coef,
+                            int size)
+{
+    int invcoef = 16384 - coef, i;
+
+    for (i = 0; i < size; i++)
+        out[i] = (coef * in1[i] + invcoef * in2[i] + 8192) >> 14;
+}
+
+static void lsf2lsp(int16_t *lsf, int16_t *lsp, int order)
+{
+    int16_t diff, freq;
+    int32_t tmp;
+    int i, k;
+
+    for (i = 0; i < order; i++) {
+        freq = (lsf[i] * 20861) >> 15;
+        /* 20861: 1.0/(2.0*PI) in Q17 */
+        /*
+           Upper 8 bits give the index k and
+           Lower 8 bits give the difference, which needs
+           to be approximated linearly
+         */
+        k = FFMIN(freq >> 8, 63);
+        diff = freq & 0xFF;
+
+        /* Calculate linear approximation */
+        tmp = cos_derivative_tbl[k] * diff;
+        lsp[i] = cos_tbl[k] + (tmp >> 12);
+    }
+}
+
+static void get_lsp_poly(int16_t *lsp, int32_t *f)
+{
+    int16_t high, low;
+    int i, j, k, l;
+    int32_t tmp;
+
+    f[0] = 16777216;
+    f[1] = lsp[0] * -1024;
+
+    for (i = 2, k = 2, l = 2; i <= 5; i++, k += 2) {
+        f[l] = f[l - 2];
+
+        for (j = i; j > 1; j--, l--) {
+            high = f[l - 1] >> 16;
+            low = (f[l - 1] - (high << 16)) >> 1;
+
+            tmp = ((high * lsp[k]) << 2) + (((low * lsp[k]) >> 15) << 2);
+
+            f[l] += f[l - 2];
+            f[l] -= tmp;
+        }
+
+        f[l] -= lsp[k] << 10;
+        l += i;
+    }
+}
+
+static void lsf2poly(int16_t *a, int16_t *lsf)
+{
+    int32_t f[2][6];
+    int16_t lsp[10];
+    int32_t tmp;
+    int i;
+
+    lsf2lsp(lsf, lsp, LPC_FILTERORDER);
+
+    get_lsp_poly(&lsp[0], f[0]);
+    get_lsp_poly(&lsp[1], f[1]);
+
+    for (i = 5; i > 0; i--) {
+        f[0][i] += f[0][i - 1];
+        f[1][i] -= f[1][i - 1];
+    }
+
+    a[0] = 4096;
+    for (i = 5; i > 0; i--) {
+        tmp = f[0][6 - i] + f[1][6 - i];
+        a[6 - i] = (tmp + 4096) >> 13;
+
+        tmp = f[0][6 - i] - f[1][6 - i];
+        a[5 + i] = (tmp + 4096) >> 13;
+    }
+}
+
+static void lsp_interpolate2polydec(int16_t *a, int16_t *lsf1,
+                                   int16_t *lsf2, int coef, int length)
+{
+    int16_t lsftmp[LPC_FILTERORDER];
+
+    lsf_interpolate(lsftmp, lsf1, lsf2, coef, length);
+    lsf2poly(a, lsftmp);
+}
+
+static void bw_expand(int16_t *out, const int16_t *in, const int16_t *coef, int length)
+{
+    int i;
+
+    out[0] = in[0];
+    for (i = 1; i < length; i++)
+        out[i] = (coef[i] * in[i] + 16384) >> 15;
+}
+
+static void lsp_interpolate(int16_t *syntdenum, int16_t *weightdenum,
+                            int16_t *lsfdeq, int16_t length,
+                            ILBCContext *s)
+{
+    int16_t lp[LPC_FILTERORDER + 1], *lsfdeq2;
+    int i, pos, lp_length;
+
+    lsfdeq2 = lsfdeq + length;
+    lp_length = length + 1;
+
+    if (s->mode == 30) {
+        lsp_interpolate2polydec(lp, (*s).lsfdeqold, lsfdeq, lsf_weight_30ms[0], length);
+        memcpy(syntdenum, lp, lp_length * 2);
+        bw_expand(weightdenum, lp, kLpcChirpSyntDenum, lp_length);
+
+        pos = lp_length;
+        for (i = 1; i < 6; i++) {
+            lsp_interpolate2polydec(lp, lsfdeq, lsfdeq2,
+                                                 lsf_weight_30ms[i],
+                                                 length);
+            memcpy(syntdenum + pos, lp, lp_length * 2);
+            bw_expand(weightdenum + pos, lp, kLpcChirpSyntDenum, lp_length);
+            pos += lp_length;
+        }
+    } else {
+        pos = 0;
+        for (i = 0; i < s->nsub; i++) {
+            lsp_interpolate2polydec(lp, s->lsfdeqold, lsfdeq,
+                                    lsf_weight_20ms[i], length);
+            memcpy(syntdenum + pos, lp, lp_length * 2);
+            bw_expand(weightdenum + pos, lp, kLpcChirpSyntDenum, lp_length);
+            pos += lp_length;
+        }
+    }
+
+    if (s->mode == 30) {
+        memcpy(s->lsfdeqold, lsfdeq2, length * 2);
+    } else {
+        memcpy(s->lsfdeqold, lsfdeq, length * 2);
+    }
+}
+
+static void filter_mafq12(int16_t *in_ptr, int16_t *out_ptr,
+                          int16_t *B, int16_t B_length,
+                          int16_t length)
+{
+    int o, i, j;
+
+    for (i = 0; i < length; i++) {
+        const int16_t *b_ptr = &B[0];
+        const int16_t *x_ptr = &in_ptr[i];
+
+        o = 0;
+        for (j = 0; j < B_length; j++)
+            o += b_ptr[j] * *x_ptr--;
+
+        o = av_clip(o, -134217728, 134215679);
+
+        out_ptr[i] = ((o + 2048) >> 12);
+    }
+}
+
+static void filter_arfq12(const int16_t *data_in,
+                          int16_t *data_out,
+                          const int16_t *coefficients,
+                          int coefficients_length,
+                          int data_length)
+{
+    int i, j;
+
+    for (i = 0; i < data_length; i++) {
+        int output = 0, sum = 0;
+
+        for (j = coefficients_length - 1; j > 0; j--) {
+            sum += coefficients[j] * data_out[i - j];
+        }
+
+        output = coefficients[0] * data_in[i] - sum;
+        output = av_clip(output, -134217728, 134215679);
+
+        data_out[i] = (output + 2048) >> 12;
+    }
+}
+
+static void state_construct(int16_t ifm, int16_t *idx,
+                           int16_t *synt_denum, int16_t *Out_fix,
+                           int16_t len)
+{
+    int k;
+    int16_t maxVal;
+    int16_t *tmp1, *tmp2, *tmp3;
+    /* Stack based */
+    int16_t numerator[1 + LPC_FILTERORDER];
+    int16_t sampleValVec[2 * STATE_SHORT_LEN_30MS + LPC_FILTERORDER];
+    int16_t sampleMaVec[2 * STATE_SHORT_LEN_30MS + LPC_FILTERORDER];
+    int16_t *sampleVal = &sampleValVec[LPC_FILTERORDER];
+    int16_t *sampleMa = &sampleMaVec[LPC_FILTERORDER];
+    int16_t *sampleAr = &sampleValVec[LPC_FILTERORDER];
+
+    /* initialization of coefficients */
+
+    for (k = 0; k < LPC_FILTERORDER + 1; k++) {
+        numerator[k] = synt_denum[LPC_FILTERORDER - k];
+    }
+
+    /* decoding of the maximum value */
+
+    maxVal = frg_quant_mod[ifm];
+
+    /* decoding of the sample values */
+    tmp1 = sampleVal;
+    tmp2 = &idx[len - 1];
+
+    if (ifm < 37) {
+        for (k = 0; k < len; k++) {
+            /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 2097152 (= 0.5 << 22)
+               maxVal is in Q8 and result is in Q(-1) */
+            (*tmp1) = (int16_t) ((SPL_MUL_16_16(maxVal, ilbc_state[(*tmp2)]) + 2097152) >> 22);
+            tmp1++;
+            tmp2--;
+        }
+    } else if (ifm < 59) {
+        for (k = 0; k < len; k++) {
+            /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 262144 (= 0.5 << 19)
+               maxVal is in Q5 and result is in Q(-1) */
+            (*tmp1) = (int16_t) ((SPL_MUL_16_16(maxVal, ilbc_state[(*tmp2)]) + 262144) >> 19);
+            tmp1++;
+            tmp2--;
+        }
+    } else {
+        for (k = 0; k < len; k++) {
+            /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 65536 (= 0.5 << 17)
+               maxVal is in Q3 and result is in Q(-1) */
+            (*tmp1) = (int16_t) ((SPL_MUL_16_16(maxVal, ilbc_state[(*tmp2)]) + 65536) >> 17);
+            tmp1++;
+            tmp2--;
+        }
+    }
+
+    /* Set the rest of the data to zero */
+    memset(&sampleVal[len], 0, len * 2);
+
+    /* circular convolution with all-pass filter */
+
+    /* Set the state to zero */
+    memset(sampleValVec, 0, LPC_FILTERORDER * 2);
+
+    /* Run MA filter + AR filter */
+    filter_mafq12(sampleVal, sampleMa, numerator, LPC_FILTERORDER + 1, len + LPC_FILTERORDER);
+    memset(&sampleMa[len + LPC_FILTERORDER], 0, (len - LPC_FILTERORDER) * 2);
+    filter_arfq12(sampleMa, sampleAr, synt_denum, LPC_FILTERORDER + 1, 2 * len);
+
+    tmp1 = &sampleAr[len - 1];
+    tmp2 = &sampleAr[2 * len - 1];
+    tmp3 = Out_fix;
+    for (k = 0; k < len; k++) {
+        (*tmp3) = (*tmp1) + (*tmp2);
+        tmp1--;
+        tmp2--;
+        tmp3++;
+    }
+}
+
+static int16_t gain_dequantization(int index, int max_in, int stage)
+{
+    int16_t scale = FFMAX(1638, FFABS(max_in));
+
+    return ((scale * ilbc_gain[stage][index]) + 8192) >> 14;
+}
+
+static void vector_rmultiplication(int16_t *out, const int16_t *in,
+                                   const int16_t *win,
+                                   int length, int shift)
+{
+    for (int i = 0; i < length; i++)
+        out[i] = (in[i] * win[-i]) >> shift;
+}
+
+static void vector_multiplication(int16_t *out, const int16_t *in,
+                                  const int16_t *win, int length,
+                                  int shift)
+{
+    for (int i = 0; i < length; i++)
+        out[i] = (in[i] * win[i]) >> shift;
+}
+
+static void add_vector_and_shift(int16_t *out, const int16_t *in1,
+                                 const int16_t *in2, int length,
+                                 int shift)
+{
+    for (int i = 0; i < length; i++)
+        out[i] = (in1[i] + in2[i]) >> shift;
+}
+
+static void create_augmented_vector(int index, int16_t *buffer, int16_t *cbVec)
+{
+    int16_t cbVecTmp[4];
+    int16_t ilow = index - 4;
+
+    memcpy(cbVec, buffer - index, index * 2);
+
+    vector_multiplication(&cbVec[ilow], buffer - index - 4, alpha, 4, 15);
+    vector_rmultiplication(cbVecTmp, buffer - 4, &alpha[3], 4, 15);
+    add_vector_and_shift(&cbVec[ilow], &cbVec[ilow], cbVecTmp, 4, 0);
+
+    memcpy(cbVec + index, buffer - index, (SUBL - index) * sizeof(*cbVec));
+}
+
+static void get_codebook(int16_t * cbvec,   /* (o) Constructed codebook vector */
+                     int16_t * mem,     /* (i) Codebook buffer */
+                     int16_t index,     /* (i) Codebook index */
+                     int16_t lMem,      /* (i) Length of codebook buffer */
+                     int16_t cbveclen   /* (i) Codebook vector length */
+)
+{
+    int16_t k, base_size;
+    int16_t lag;
+    /* Stack based */
+    int16_t tempbuff2[SUBL + 5];
+
+    /* Determine size of codebook sections */
+    base_size = lMem - cbveclen + 1;
+
+    if (cbveclen == SUBL) {
+        base_size += cbveclen / 2;
+    }
+
+    /* No filter -> First codebook section */
+    if (index < lMem - cbveclen + 1) {
+        /* first non-interpolated vectors */
+
+        k = index + cbveclen;
+        /* get vector */
+        memcpy(cbvec, mem + lMem - k, cbveclen * 2);
+    } else if (index < base_size) {
+
+        /* Calculate lag */
+
+        k = (int16_t) SPL_MUL_16_16(2, (index - (lMem - cbveclen + 1))) + cbveclen;
+
+        lag = k / 2;
+
+        create_augmented_vector(lag, mem + lMem, cbvec);
+    } else {
+        int16_t memIndTest;
+
+        /* first non-interpolated vectors */
+
+        if (index - base_size < lMem - cbveclen + 1) {
+
+            /* Set up filter memory, stuff zeros outside memory buffer */
+
+            memIndTest = lMem - (index - base_size + cbveclen);
+
+            memset(mem - CB_HALFFILTERLEN, 0, CB_HALFFILTERLEN * 2);
+            memset(mem + lMem, 0, CB_HALFFILTERLEN * 2);
+
+            /* do filtering to get the codebook vector */
+
+            filter_mafq12(&mem[memIndTest + 4], cbvec, (int16_t *) kCbFiltersRev, CB_FILTERLEN, cbveclen);
+        } else {
+            /* interpolated vectors */
+            /* Stuff zeros outside memory buffer  */
+            memIndTest = lMem - cbveclen - CB_FILTERLEN;
+            memset(mem + lMem, 0, CB_HALFFILTERLEN * 2);
+
+            /* do filtering */
+            filter_mafq12(&mem[memIndTest + 7], tempbuff2, (int16_t *) kCbFiltersRev, CB_FILTERLEN, (int16_t) (cbveclen + 5));
+
+            /* Calculate lag index */
+            lag = (cbveclen << 1) - 20 + index - base_size - lMem - 1;
+
+            create_augmented_vector(lag, tempbuff2 + SUBL + 5, cbvec);
+        }
+    }
+}
+
+static void construct_vector (
+    int16_t *decvector,   /* (o) Decoded vector */
+    int16_t *index,       /* (i) Codebook indices */
+    int16_t *gain_index,  /* (i) Gain quantization indices */
+    int16_t *mem,         /* (i) Buffer for codevector construction */
+    int16_t lMem,         /* (i) Length of buffer */
+    int16_t veclen)
+{
+    int16_t gain[CB_NSTAGES];
+    int16_t cbvec0[SUBL];
+    int16_t cbvec1[SUBL];
+    int16_t cbvec2[SUBL];
+    int32_t a32;
+    int16_t *gainPtr;
+    int j;
+
+    /* gain de-quantization */
+
+    gain[0] = gain_dequantization(gain_index[0], 16384, 0);
+    gain[1] = gain_dequantization(gain_index[1], gain[0], 1);
+    gain[2] = gain_dequantization(gain_index[2], gain[1], 2);
+
+    /* codebook vector construction and construction of total vector */
+
+    /* Stack based */
+    get_codebook(cbvec0, mem, index[0], lMem, veclen);
+    get_codebook(cbvec1, mem, index[1], lMem, veclen);
+    get_codebook(cbvec2, mem, index[2], lMem, veclen);
+
+    gainPtr = &gain[0];
+    for (j = 0; j < veclen; j++) {
+        a32 = SPL_MUL_16_16(*gainPtr++, cbvec0[j]);
+        a32 += SPL_MUL_16_16(*gainPtr++, cbvec1[j]);
+        a32 += SPL_MUL_16_16(*gainPtr, cbvec2[j]);
+        gainPtr -= 2;
+        decvector[j] = (a32 + 8192) >> 14;
+    }
+}
+
+static void reverse_memcpy(int16_t *dest, int16_t *source, int length)
+{
+    int16_t* destPtr = dest;
+    int16_t* sourcePtr = source;
+    int j;
+
+    for (j = 0; j < length; j++)
+        *destPtr-- = *sourcePtr++;
+}
+
+static void decode_residual(ILBCContext *s,
+                            ILBCFrame *encbits,
+                            int16_t *decresidual,
+                            int16_t *syntdenum)
+{
+    int16_t meml_gotten, Nfor, Nback, diff, start_pos;
+    int16_t subcount, subframe;
+    int16_t *reverseDecresidual = s->enh_buf;        /* Reversed decoded data, used for decoding backwards in time (reuse memory in state) */
+    int16_t *memVec = s->prevResidual;
+    int16_t *mem = &memVec[CB_HALFFILTERLEN];   /* Memory for codebook */
+
+    diff = STATE_LEN - s->state_short_len;
+
+    if (encbits->state_first == 1) {
+        start_pos = (encbits->start - 1) * SUBL;
+    } else {
+        start_pos = (encbits->start - 1) * SUBL + diff;
+    }
+
+    /* decode scalar part of start state */
+
+    state_construct(encbits->ifm, encbits->idx, &syntdenum[(encbits->start - 1) * (LPC_FILTERORDER + 1)], &decresidual[start_pos], s->state_short_len);
+
+    if (encbits->state_first) { /* put adaptive part in the end */
+        /* setup memory */
+        memset(mem, 0, (int16_t) (CB_MEML - s->state_short_len) * 2);
+        memcpy(mem + CB_MEML - s->state_short_len, decresidual + start_pos, s->state_short_len * 2);
+
+        /* construct decoded vector */
+
+        construct_vector(&decresidual[start_pos + s->state_short_len], encbits->cb_index, encbits->gain_index, mem + CB_MEML - ST_MEM_L_TBL, ST_MEM_L_TBL, (int16_t) diff);
+
+    } else { /* put adaptive part in the beginning */
+        /* setup memory */
+        meml_gotten = s->state_short_len;
+        reverse_memcpy(mem + CB_MEML - 1, decresidual + start_pos, meml_gotten);
+        memset(mem, 0, (int16_t) (CB_MEML - meml_gotten) * 2);
+
+        /* construct decoded vector */
+        construct_vector(reverseDecresidual, encbits->cb_index, encbits->gain_index, mem + CB_MEML - ST_MEM_L_TBL, ST_MEM_L_TBL, diff);
+
+        /* get decoded residual from reversed vector */
+        reverse_memcpy(&decresidual[start_pos - 1], reverseDecresidual, diff);
+    }
+
+    /* counter for predicted subframes */
+    subcount = 1;
+
+    /* forward prediction of subframes */
+    Nfor = s->nsub - encbits->start - 1;
+
+    if (Nfor > 0) {
+        /* setup memory */
+        memset(mem, 0, (CB_MEML - STATE_LEN) * 2);
+        memcpy(mem + CB_MEML - STATE_LEN, decresidual + (encbits->start - 1) * SUBL, STATE_LEN * 2);
+
+        /* loop over subframes to encode */
+        for (subframe = 0; subframe < Nfor; subframe++) {
+            /* construct decoded vector */
+            construct_vector(&decresidual[(encbits->start + 1 + subframe) * SUBL], encbits->cb_index + subcount * CB_NSTAGES, encbits->gain_index + subcount * CB_NSTAGES, mem, MEM_LF_TBL, SUBL);
+
+            /* update memory */
+            memmove(mem, mem + SUBL, (CB_MEML - SUBL) * sizeof(*mem));
+            memcpy(mem + CB_MEML - SUBL, &decresidual[(encbits->start + 1 + subframe) * SUBL], SUBL * 2);
+
+            subcount++;
+        }
+
+    }
+
+    /* backward prediction of subframes */
+    Nback = encbits->start - 1;
+
+    if (Nback > 0) {
+        /* setup memory */
+        meml_gotten = SUBL * (s->nsub + 1 - encbits->start);
+        if (meml_gotten > CB_MEML) {
+            meml_gotten = CB_MEML;
+        }
+
+        reverse_memcpy(mem + CB_MEML - 1, decresidual + (encbits->start - 1) * SUBL, meml_gotten);
+        memset(mem, 0, (int16_t) (CB_MEML - meml_gotten) * 2);
+
+        /* loop over subframes to decode */
+        for (subframe = 0; subframe < Nback; subframe++) {
+            /* construct decoded vector */
+            construct_vector(&reverseDecresidual[subframe * SUBL], encbits->cb_index + subcount * CB_NSTAGES,
+                        encbits->gain_index + subcount * CB_NSTAGES, mem, MEM_LF_TBL, SUBL);
+
+            /* update memory */
+            memmove(mem, mem + SUBL, (CB_MEML - SUBL) * sizeof(*mem));
+            memcpy(mem + CB_MEML - SUBL, &reverseDecresidual[subframe * SUBL], SUBL * 2);
+
+            subcount++;
+        }
+
+        /* get decoded residual from reversed vector */
+        reverse_memcpy(decresidual + SUBL * Nback - 1, reverseDecresidual, SUBL * Nback);
+    }
+}
+
+static int16_t max_abs_value_w16(const int16_t* vector, int length)
+{
+    int i = 0, absolute = 0, maximum = 0;
+
+    if (vector == NULL || length <= 0) {
+        return -1;
+    }
+
+    for (i = 0; i < length; i++) {
+        absolute = FFABS(vector[i]);
+        if (absolute > maximum)
+            maximum = absolute;
+    }
+
+    // Guard the case for abs(-32768).
+    return FFMIN(maximum, INT16_MAX);
+}
+
+static int16_t get_size_in_bits(uint32_t n)
+{
+    int16_t bits;
+
+    if (0xFFFF0000 & n) {
+        bits = 16;
+    } else {
+        bits = 0;
+    }
+
+    if (0x0000FF00 & (n >> bits)) bits += 8;
+    if (0x000000F0 & (n >> bits)) bits += 4;
+    if (0x0000000C & (n >> bits)) bits += 2;
+    if (0x00000002 & (n >> bits)) bits += 1;
+    if (0x00000001 & (n >> bits)) bits += 1;
+
+    return bits;
+}
+
+static int32_t scale_dot_product(const int16_t *v1, const int16_t *v2, int length, int scaling)
+{
+    int32_t sum = 0;
+
+    for (int i = 0; i < length; i++)
+        sum += (v1[i] * v2[i]) >> scaling;
+
+    return sum;
+}
+
+static void correlation(int32_t *corr, int32_t *ener, int16_t *buffer,
+                        int16_t lag, int16_t blen, int16_t srange, int16_t scale)
+{
+    int16_t *w16ptr;
+
+    w16ptr = &buffer[blen - srange - lag];
+
+    *corr = scale_dot_product(&buffer[blen - srange], w16ptr, srange, scale);
+    *ener = scale_dot_product(w16ptr, w16ptr, srange, scale);
+
+    if (*ener == 0) {
+        *corr = 0;
+        *ener = 1;
+    }
+}
+
+#define SPL_SHIFT_W32(x, c) (((c) >= 0) ? ((x) << (c)) : ((x) >> (-(c))))
+
+static int16_t norm_w32(int32_t a)
+{
+    if (a == 0) {
+        return 0;
+    } else if (a < 0) {
+        a = ~a;
+    }
+
+    return ff_clz(a);
+}
+
+static int32_t div_w32_w16(int32_t num, int16_t den)
+{
+    if (den != 0)
+        return num / den;
+    else
+        return 0x7FFFFFFF;
+}
+
+static void do_plc(int16_t *plc_residual,      /* (o) concealed residual */
+                   int16_t *plc_lpc,           /* (o) concealed LP parameters */
+                   int16_t PLI,                /* (i) packet loss indicator
+                                                      0 - no PL, 1 = PL */
+                   int16_t *decresidual,       /* (i) decoded residual */
+                   int16_t *lpc,               /* (i) decoded LPC (only used for no PL) */
+                   int16_t inlag,              /* (i) pitch lag */
+                   ILBCContext *s)             /* (i/o) decoder instance */
+{
+    int16_t i, pick;
+    int32_t cross, ener, cross_comp, ener_comp = 0;
+    int32_t measure, max_measure, energy;
+    int16_t max, cross_square_max, cross_square;
+    int16_t j, lag, tmp1, tmp2, randlag;
+    int16_t shift1, shift2, shift3, shift_max;
+    int16_t scale3;
+    int16_t corrLen;
+    int32_t tmpW32, tmp2W32;
+    int16_t use_gain;
+    int16_t tot_gain;
+    int16_t max_perSquare;
+    int16_t scale1, scale2;
+    int16_t totscale;
+    int32_t nom;
+    int16_t denom;
+    int16_t pitchfact;
+    int16_t use_lag;
+    int ind;
+    int16_t randvec[BLOCKL_MAX];
+
+    /* Packet Loss */
+    if (PLI == 1) {
+
+        s->consPLICount += 1;
+
+        /* if previous frame not lost,
+           determine pitch pred. gain */
+
+        if (s->prevPLI != 1) {
+
+            /* Maximum 60 samples are correlated, preserve as high accuracy
+               as possible without getting overflow */
+            max = max_abs_value_w16(s->prevResidual, s->block_samples);
+            scale3 = (get_size_in_bits(max) << 1) - 25;
+            if (scale3 < 0) {
+                scale3 = 0;
+            }
+
+            /* Store scale for use when interpolating between the
+             * concealment and the received packet */
+            s->prevScale = scale3;
+
+            /* Search around the previous lag +/-3 to find the
+               best pitch period */
+            lag = inlag - 3;
+
+            /* Guard against getting outside the frame */
+            corrLen = FFMIN(60, s->block_samples - (inlag + 3));
+
+            correlation(&cross, &ener, s->prevResidual, lag, s->block_samples, corrLen, scale3);
+
+            /* Normalize and store cross^2 and the number of shifts */
+            shift_max = get_size_in_bits(FFABS(cross)) - 15;
+            cross_square_max = (int16_t) SPL_MUL_16_16_RSFT(SPL_SHIFT_W32(cross, -shift_max), SPL_SHIFT_W32(cross, -shift_max), 15);
+
+            for (j = inlag - 2; j <= inlag + 3; j++) {
+                correlation(&cross_comp, &ener_comp, s->prevResidual, j, s->block_samples, corrLen, scale3);
+
+                /* Use the criteria (corr*corr)/energy to compare if
+                   this lag is better or not. To avoid the division,
+                   do a cross multiplication */
+                shift1 = get_size_in_bits(FFABS(cross_comp)) - 15;
+                cross_square = (int16_t) SPL_MUL_16_16_RSFT(SPL_SHIFT_W32(cross_comp, -shift1), SPL_SHIFT_W32(cross_comp, -shift1), 15);
+
+                shift2 = get_size_in_bits(ener) - 15;
+                measure = SPL_MUL_16_16(SPL_SHIFT_W32(ener, -shift2), cross_square);
+
+                shift3 = get_size_in_bits(ener_comp) - 15;
+                max_measure = SPL_MUL_16_16(SPL_SHIFT_W32(ener_comp, -shift3), cross_square_max);
+
+                /* Calculate shift value, so that the two measures can
+                   be put in the same Q domain */
+                if (((shift_max << 1) + shift3) > ((shift1 << 1) + shift2)) {
+                    tmp1 = FFMIN(31, (shift_max << 1) + shift3 - (shift1 << 1) - shift2);
+                    tmp2 = 0;
+                } else {
+                    tmp1 = 0;
+                    tmp2 = FFMIN(31, (shift1 << 1) + shift2 - (shift_max << 1) - shift3);
+                }
+
+                if ((measure >> tmp1) > (max_measure >> tmp2)) {
+                    /* New lag is better => record lag, measure and domain */
+                    lag = j;
+                    cross_square_max = cross_square;
+                    cross = cross_comp;
+                    shift_max = shift1;
+                    ener = ener_comp;
+                }
+            }
+
+            /* Calculate the periodicity for the lag with the maximum correlation.
+
+               Definition of the periodicity:
+               abs(corr(vec1, vec2))/(sqrt(energy(vec1))*sqrt(energy(vec2)))
+
+               Work in the Square domain to simplify the calculations
+               max_perSquare is less than 1 (in Q15)
+             */
+            tmp2W32 = scale_dot_product(&s->prevResidual[s->block_samples - corrLen], &s->prevResidual[s->block_samples - corrLen], corrLen, scale3);
+
+            if ((tmp2W32 > 0) && (ener_comp > 0)) {
+                /* norm energies to int16_t, compute the product of the energies and
+                   use the upper int16_t as the denominator */
+
+                scale1 = norm_w32(tmp2W32) - 16;
+                tmp1 = SPL_SHIFT_W32(tmp2W32, scale1);
+
+                scale2 = norm_w32(ener) - 16;
+                tmp2 =  SPL_SHIFT_W32(ener, scale2);
+                denom = SPL_MUL_16_16_RSFT(tmp1, tmp2, 16);    /* denom in Q(scale1+scale2-16) */
+
+                /* Square the cross correlation and norm it such that max_perSquare
+                   will be in Q15 after the division */
+
+                totscale = scale1 + scale2 - 1;
+                tmp1 = SPL_SHIFT_W32(cross, (totscale >> 1));
+                tmp2 = SPL_SHIFT_W32(cross, totscale - (totscale >> 1));
+
+                nom = SPL_MUL_16_16(tmp1, tmp2);
+                max_perSquare = div_w32_w16(nom, denom);
+            } else {
+                max_perSquare = 0;
+            }
+        } else {
+            /* previous frame lost, use recorded lag and gain */
+            lag = s->prevLag;
+            max_perSquare = s->per_square;
+        }
+
+        /* Attenuate signal and scale down pitch pred gain if
+           several frames lost consecutively */
+
+        use_gain = 32767;       /* 1.0 in Q15 */
+
+        if (s->consPLICount * s->block_samples > 320) {
+            use_gain = 29491;   /* 0.9 in Q15 */
+        } else if (s->consPLICount * s->block_samples > 640) {
+            use_gain = 22938;   /* 0.7 in Q15 */
+        } else if (s->consPLICount * s->block_samples > 960) {
+            use_gain = 16384;   /* 0.5 in Q15 */
+        } else if (s->consPLICount * s->block_samples > 1280) {
+            use_gain = 0;       /* 0.0 in Q15 */
+        }
+
+        /* Compute mixing factor of picth repeatition and noise:
+           for max_per>0.7 set periodicity to 1.0
+           0.4<max_per<0.7 set periodicity to (maxper-0.4)/0.7-0.4)
+           max_per<0.4 set periodicity to 0.0
+         */
+
+        if (max_perSquare > 7868) {     /* periodicity > 0.7  (0.7^4=0.2401 in Q15) */
+            pitchfact = 32767;
+        } else if (max_perSquare > 839) {       /* 0.4 < periodicity < 0.7 (0.4^4=0.0256 in Q15) */
+            /* find best index and interpolate from that */
+            ind = 5;
+            while ((max_perSquare < kPlcPerSqr[ind]) && (ind > 0)) {
+                ind--;
+            }
+            /* pitch fact is approximated by first order */
+            tmpW32 = kPlcPitchFact[ind] + SPL_MUL_16_16_RSFT(kPlcPfSlope[ind], (max_perSquare - kPlcPerSqr[ind]), 11);
+
+            pitchfact = FFMIN(tmpW32, 32767); /* guard against overflow */
+
+        } else {                /* periodicity < 0.4 */
+            pitchfact = 0;
+        }
+
+        /* avoid repetition of same pitch cycle (buzzyness) */
+        use_lag = lag;
+        if (lag < 80) {
+            use_lag = 2 * lag;
+        }
+
+        /* compute concealed residual */
+        energy = 0;
+
+        for (i = 0; i < s->block_samples; i++) {
+            /* noise component -  52 < randlagFIX < 117 */
+            s->seed = SPL_MUL_16_16(s->seed, 31821) + 13849;
+            randlag = 53 + (s->seed & 63);
+
+            pick = i - randlag;
+
+            if (pick < 0) {
+                randvec[i] = s->prevResidual[s->block_samples + pick];
+            } else {
+                randvec[i] = s->prevResidual[pick];
+            }
+
+            /* pitch repeatition component */
+            pick = i - use_lag;
+
+            if (pick < 0) {
+                plc_residual[i] = s->prevResidual[s->block_samples + pick];
+            } else {
+                plc_residual[i] = plc_residual[pick];
+            }
+
+            /* Attinuate total gain for each 10 ms */
+            if (i < 80) {
+                tot_gain = use_gain;
+            } else if (i < 160) {
+                tot_gain = SPL_MUL_16_16_RSFT(31130, use_gain, 15);    /* 0.95*use_gain */
+            } else {
+                tot_gain = SPL_MUL_16_16_RSFT(29491, use_gain, 15);    /* 0.9*use_gain */
+            }
+
+            /* mix noise and pitch repeatition */
+            plc_residual[i] = SPL_MUL_16_16_RSFT(tot_gain, (pitchfact * plc_residual[i] + (32767 - pitchfact) * randvec[i] + 16384) >> 15, 15);
+
+            /* Shifting down the result one step extra to ensure that no overflow
+               will occur */
+            energy += SPL_MUL_16_16_RSFT(plc_residual[i], plc_residual[i], (s->prevScale + 1));
+
+        }
+
+        /* less than 30 dB, use only noise */
+        if (energy < SPL_SHIFT_W32(s->block_samples * 900, -s->prevScale - 1)) {
+            energy = 0;
+            for (i = 0; i < s->block_samples; i++) {
+                plc_residual[i] = randvec[i];
+            }
+        }
+
+        /* use the old LPC */
+        memcpy(plc_lpc, (*s).prev_lpc, (LPC_FILTERORDER + 1) * 2);
+
+        /* Update state in case there are multiple frame losses */
+        s->prevLag = lag;
+        s->per_square = max_perSquare;
+    } else { /* no packet loss, copy input */
+        memcpy(plc_residual, decresidual, s->block_samples * 2);
+        memcpy(plc_lpc, lpc, (LPC_FILTERORDER + 1) * 2);
+        s->consPLICount = 0;
+    }
+
+    /* update state */
+    s->prevPLI = PLI;
+    memcpy(s->prev_lpc, plc_lpc, (LPC_FILTERORDER + 1) * 2);
+    memcpy(s->prevResidual, plc_residual, s->block_samples * 2);
+
+    return;
+}
+
+static int xcorr_coeff(int16_t *target, int16_t *regressor,
+                       int16_t subl, int16_t searchLen,
+                       int16_t offset, int16_t step)
+{
+    int16_t maxlag;
+    int16_t pos;
+    int16_t max;
+    int16_t cross_corr_scale, energy_scale;
+    int16_t cross_corr_sg_mod, cross_corr_sg_mod_max;
+    int32_t cross_corr, energy;
+    int16_t cross_corr_mod, energy_mod, enery_mod_max;
+    int16_t *tp, *rp;
+    int16_t *rp_beg, *rp_end;
+    int16_t totscale, totscale_max;
+    int16_t scalediff;
+    int32_t new_crit, max_crit;
+    int shifts;
+    int k;
+
+    /* Initializations, to make sure that the first one is selected */
+    cross_corr_sg_mod_max = 0;
+    enery_mod_max = INT16_MAX;
+    totscale_max = -500;
+    maxlag = 0;
+    pos = 0;
+
+    /* Find scale value and start position */
+    if (step == 1) {
+        max = max_abs_value_w16(regressor, (int16_t) (subl + searchLen - 1));
+        rp_beg = regressor;
+        rp_end = &regressor[subl];
+    } else {                    /* step== -1 */
+        max = max_abs_value_w16(&regressor[-searchLen], (int16_t) (subl + searchLen - 1));
+        rp_beg = &regressor[-1];
+        rp_end = &regressor[subl - 1];
+    }
+
+    /* Introduce a scale factor on the energy in int32_t in
+       order to make sure that the calculation does not
+       overflow */
+
+    if (max > 5000) {
+        shifts = 2;
+    } else {
+        shifts = 0;
+    }
+
+    /* Calculate the first energy, then do a +/- to get the other energies */
+    energy = scale_dot_product(regressor, regressor, subl, shifts);
+
+    for (k = 0; k < searchLen; k++) {
+        tp = target;
+        rp = &regressor[pos];
+
+        cross_corr = scale_dot_product(tp, rp, subl, shifts);
+
+        if ((energy > 0) && (cross_corr > 0)) {
+            /* Put cross correlation and energy on 16 bit word */
+            cross_corr_scale = norm_w32(cross_corr) - 16;
+            cross_corr_mod = (int16_t) SPL_SHIFT_W32(cross_corr, cross_corr_scale);
+            energy_scale = norm_w32(energy) - 16;
+            energy_mod = (int16_t) SPL_SHIFT_W32(energy, energy_scale);
+
+            /* Square cross correlation and store upper int16_t */
+            cross_corr_sg_mod = (int16_t) SPL_MUL_16_16_RSFT(cross_corr_mod, cross_corr_mod, 16);
+
+            /* Calculate the total number of (dynamic) right shifts that have
+               been performed on (cross_corr*cross_corr)/energy
+             */
+            totscale = energy_scale - (cross_corr_scale << 1);
+
+            /* Calculate the shift difference in order to be able to compare the two
+               (cross_corr*cross_corr)/energy in the same domain
+             */
+            scalediff = totscale - totscale_max;
+            scalediff = FFMIN(scalediff, 31);
+            scalediff = FFMAX(scalediff, -31);
+
+            /* Compute the cross multiplication between the old best criteria
+               and the new one to be able to compare them without using a
+               division */
+
+            if (scalediff < 0) {
+                new_crit = ((int32_t) cross_corr_sg_mod * enery_mod_max) >> (-scalediff);
+                max_crit = ((int32_t) cross_corr_sg_mod_max * energy_mod);
+            } else {
+                new_crit = ((int32_t) cross_corr_sg_mod * enery_mod_max);
+                max_crit = ((int32_t) cross_corr_sg_mod_max * energy_mod) >> scalediff;
+            }
+
+            /* Store the new lag value if the new criteria is larger
+               than previous largest criteria */
+
+            if (new_crit > max_crit) {
+                cross_corr_sg_mod_max = cross_corr_sg_mod;
+                enery_mod_max = energy_mod;
+                totscale_max = totscale;
+                maxlag = k;
+            }
+        }
+        pos += step;
+
+        /* Do a +/- to get the next energy */
+        energy += step * ((*rp_end * *rp_end - *rp_beg * *rp_beg) >> shifts);
+        rp_beg += step;
+        rp_end += step;
+    }
+
+    return maxlag + offset;
+}
+
+static void hp_output(int16_t *signal, const int16_t *ba, int16_t *y,
+                      int16_t *x, int16_t len)
+{
+    int32_t tmp;
+
+    for (int i = 0; i < len; i++) {
+        tmp = SPL_MUL_16_16(y[1], ba[3]);     /* (-a[1])*y[i-1] (low part) */
+        tmp += SPL_MUL_16_16(y[3], ba[4]);    /* (-a[2])*y[i-2] (low part) */
+        tmp = (tmp >> 15);
+        tmp += SPL_MUL_16_16(y[0], ba[3]);    /* (-a[1])*y[i-1] (high part) */
+        tmp += SPL_MUL_16_16(y[2], ba[4]);    /* (-a[2])*y[i-2] (high part) */
+        tmp = (tmp << 1);
+
+        tmp += SPL_MUL_16_16(signal[i], ba[0]);       /* b[0]*x[0] */
+        tmp += SPL_MUL_16_16(x[0], ba[1]);    /* b[1]*x[i-1] */
+        tmp += SPL_MUL_16_16(x[1], ba[2]);    /* b[2]*x[i-2] */
+
+        /* Update state (input part) */
+        x[1] = x[0];
+        x[0] = signal[i];
+
+        /* Convert back to Q0 and multiply with 2 */
+        signal[i] = av_clip_intp2(tmp + 1024, 26) >> 11;
+
+        /* Update state (filtered part) */
+        y[2] = y[0];
+        y[3] = y[1];
+
+        /* upshift tmp by 3 with saturation */
+        if (tmp > 268435455) {
+            tmp = INT32_MAX;
+        } else if (tmp < -268435456) {
+            tmp = INT32_MIN;
+        } else {
+            tmp = tmp << 3;
+        }
+
+        y[0] = tmp >> 16;
+        y[1] = (tmp - (y[0] << 16)) >> 1;
+    }
+}
+
+static int ilbc_decode_frame(AVCodecContext *avctx, void *data,
+                             int *got_frame_ptr, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    AVFrame *frame     = data;
+    ILBCContext *s     = avctx->priv_data;
+    int mode = s->mode, ret;
+    int16_t *plc_data = &s->plc_residual[LPC_FILTERORDER];
+
+    if ((ret = init_get_bits8(&s->gb, buf, avpkt->size)) < 0)
+        return ret;
+    memset(&s->frame, 0, sizeof(ILBCFrame));
+
+    frame->nb_samples = s->block_samples;
+    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
+        return ret;
+
+    if (unpack_frame(s))
+        mode = 0;
+    if (s->frame.start < 1)
+        mode = 0;
+
+    if (mode) {
+        index_conv(s->frame.cb_index);
+
+        lsf_dequantization(s->lsfdeq, s->frame.lsf, s->lpc_n);
+        lsf_check_stability(s->lsfdeq, LPC_FILTERORDER, s->lpc_n);
+        lsp_interpolate(s->syntdenum, s->weightdenum,
+                        s->lsfdeq, LPC_FILTERORDER, s);
+        decode_residual(s, &s->frame, s->decresidual, s->syntdenum);
+
+        do_plc(s->plc_residual, s->plc_lpc, 0,
+                               s->decresidual, s->syntdenum + (LPC_FILTERORDER + 1) * (s->nsub - 1),
+                               s->last_lag, s);
+
+        memcpy(s->decresidual, s->plc_residual, s->block_samples * 2);
+    }
+
+    if (s->enhancer) {
+        /* TODO */
+    } else {
+        int16_t lag, i;
+
+        /* Find last lag (since the enhancer is not called to give this info) */
+        if (s->mode == 20) {
+            lag = xcorr_coeff(&s->decresidual[s->block_samples-60], &s->decresidual[s->block_samples-80],
+                              60, 80, 20, -1);
+        } else {
+            lag = xcorr_coeff(&s->decresidual[s->block_samples-ENH_BLOCKL],
+                              &s->decresidual[s->block_samples-ENH_BLOCKL-20],
+                              ENH_BLOCKL, 100, 20, -1);
+        }
+
+        /* Store lag (it is needed if next packet is lost) */
+        s->last_lag = lag;
+
+        /* copy data and run synthesis filter */
+        memcpy(plc_data, s->decresidual, s->block_samples * 2);
+
+        /* Set up the filter state */
+        memcpy(&plc_data[-LPC_FILTERORDER], s->syntMem, LPC_FILTERORDER * 2);
+
+        for (i = 0; i < s->nsub; i++) {
+            filter_arfq12(plc_data+i*SUBL, plc_data+i*SUBL,
+                                      s->syntdenum + i*(LPC_FILTERORDER + 1),
+                                      LPC_FILTERORDER + 1, SUBL);
+        }
+
+        /* Save the filter state */
+        memcpy(s->syntMem, &plc_data[s->block_samples-LPC_FILTERORDER], LPC_FILTERORDER * 2);
+    }
+
+    memcpy(frame->data[0], plc_data, s->block_samples * 2);
+
+    hp_output((int16_t *)frame->data[0], hp_out_coeffs,
+              s->hpimemy, s->hpimemx, s->block_samples);
+
+    memcpy(s->old_syntdenum, s->syntdenum, s->nsub*(LPC_FILTERORDER + 1) * 2);
+
+    s->prev_enh_pl = 0;
+    if (mode == 0)
+        s->prev_enh_pl = 1;
+
+    *got_frame_ptr = 1;
+
+    return avpkt->size;
+}
+
+static av_cold int ilbc_decode_init(AVCodecContext *avctx)
+{
+    ILBCContext *s  = avctx->priv_data;
+
+    if (avctx->block_align == 38)
+        s->mode = 20;
+    else if (avctx->block_align == 50)
+        s->mode = 30;
+    else if (avctx->bit_rate > 0)
+        s->mode = avctx->bit_rate <= 14000 ? 30 : 20;
+    else
+        return AVERROR_INVALIDDATA;
+
+    avctx->channels       = 1;
+    avctx->channel_layout = AV_CH_LAYOUT_MONO;
+    avctx->sample_rate    = 8000;
+    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;
+
+    if (s->mode == 30) {
+        s->block_samples = 240;
+        s->nsub = NSUB_30MS;
+        s->nasub = NASUB_30MS;
+        s->lpc_n = LPC_N_30MS;
+        s->state_short_len = STATE_SHORT_LEN_30MS;
+    } else {
+        s->block_samples = 160;
+        s->nsub = NSUB_20MS;
+        s->nasub = NASUB_20MS;
+        s->lpc_n = LPC_N_20MS;
+        s->state_short_len = STATE_SHORT_LEN_20MS;
+    }
+
+    return 0;
+}
+
+AVCodec ff_ilbc_decoder = {
+    .name           = "ilbc",
+    .long_name      = NULL_IF_CONFIG_SMALL("iLBC (Internet Low Bitrate Codec)"),
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_ILBC,
+    .init           = ilbc_decode_init,
+    .decode         = ilbc_decode_frame,
+    .capabilities   = AV_CODEC_CAP_DR1,
+    .priv_data_size = sizeof(ILBCContext),
+};