TwinVQ decoder

Originally committed as revision 19682 to svn://svn.ffmpeg.org/ffmpeg/trunk

Changelog

@@ -33,6 +33,7 @@ version <next>:
 - noX handling for OPT_BOOL X options
 - Wave64 demuxer
 - IEC-61937 compatible Muxer
+- TwinVQ decoder
 
 
 

doc/general.texi

@@ -613,6 +613,7 @@ following image formats are supported:
 @item True Audio (TTA)       @tab     @tab  X
 @item TrueHD                 @tab     @tab  X
     @tab Used in HD-DVD and Blu-Ray discs.
+@item TwinVQ (VQF flavor)    @tab     @tab  X
 @item Vorbis                 @tab  E  @tab  X
     @ A native but very primitive encoder exists.
 @item WavPack                @tab     @tab  X

libavcodec/Makefile

@@ -227,6 +227,7 @@ OBJS-$(CONFIG_TRUEMOTION2_DECODER)     += truemotion2.o
 OBJS-$(CONFIG_TRUESPEECH_DECODER)      += truespeech.o
 OBJS-$(CONFIG_TSCC_DECODER)            += tscc.o msrledec.o
 OBJS-$(CONFIG_TTA_DECODER)             += tta.o
+OBJS-$(CONFIG_TWINVQ_DECODER)          += twinvq.o
 OBJS-$(CONFIG_TXD_DECODER)             += txd.o s3tc.o
 OBJS-$(CONFIG_ULTI_DECODER)            += ulti.o
 OBJS-$(CONFIG_V210_DECODER)            += v210dec.o

libavcodec/allcodecs.c

@@ -228,6 +228,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (TRUEHD, truehd);
     REGISTER_DECODER (TRUESPEECH, truespeech);
     REGISTER_DECODER (TTA, tta);
+    REGISTER_DECODER (TWINVQ, twinvq);
     REGISTER_DECODER (VMDAUDIO, vmdaudio);
     REGISTER_ENCDEC  (VORBIS, vorbis);
     REGISTER_DECODER (WAVPACK, wavpack);

libavcodec/twinvq.c

+/*
+ * TwinVQ decoder
+ * Copyright (c) 2009 Vitor Sessak
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "get_bits.h"
+#include "dsputil.h"
+
+#include <math.h>
+#include <stdint.h>
+
+#include "twinvq_data.h"
+
+enum FrameType {
+    FT_SHORT = 0,  ///< Short frame  (divided in n   sub-blocks)
+    FT_MEDIUM,     ///< Medium frame (divided in m<n sub-blocks)
+    FT_LONG,       ///< Long frame   (single sub-block + PPC)
+    FT_PPC,        ///< Periodic Peak Component (part of the long frame)
+};
+
+/**
+ * Parameters and tables that are different for each frame type
+ */
+struct FrameMode {
+    uint8_t         sub;      ///< Number subblocks in each frame
+    const uint16_t *bark_tab;
+
+    /** number of distinct bark scale envelope values */
+    uint8_t         bark_env_size;
+
+    const int16_t  *bark_cb;    ///< codebook for the bark scale envelope (BSE)
+    uint8_t         bark_n_coef;///< number of BSE CB coefficients to read
+    uint8_t         bark_n_bit; ///< number of bits of the BSE coefs
+
+    //@{
+    /** main codebooks for spectrum data */
+    const int16_t    *cb0;
+    const int16_t    *cb1;
+    //@}
+
+    uint8_t         cb_len_read; ///< number of spectrum coefficients to read
+};
+
+/**
+ * Parameters and tables that are different for every combination of
+ * bitrate/sample rate
+ */
+typedef struct {
+    struct FrameMode fmode[3]; ///< frame type-dependant parameters
+
+    uint16_t     size;        ///< frame size in samples
+    uint8_t      n_lsp;       ///< number of lsp coefficients
+    const float *lspcodebook;
+
+    /* number of bits of the different LSP CB coefficients */
+    uint8_t      lsp_bit0;
+    uint8_t      lsp_bit1;
+    uint8_t      lsp_bit2;
+
+    uint8_t      lsp_split;      ///< number of CB entries for the LSP decoding
+    const int16_t *ppc_shape_cb; ///< PPC shape CB
+
+    /** number of the bits for the PPC period value */
+    uint8_t      ppc_period_bit;
+
+    uint8_t      ppc_shape_bit;  ///< number of bits of the PPC shape CB coeffs
+    uint8_t      ppc_shape_len;  ///< size of PPC shape CB
+    uint8_t      pgain_bit;      ///< bits for PPC gain
+
+    /** constant for peak period to peak width conversion */
+    uint16_t     peak_per2wid;
+} ModeTab;
+
+static const ModeTab mode_08_08 = {
+    {
+        { 8, bark_tab_s08_64,  10, tab.fcb08s  , 1, 5, tab.cb0808s0, tab.cb0808s1, 18},
+        { 2, bark_tab_m08_256, 20, tab.fcb08m  , 2, 5, tab.cb0808m0, tab.cb0808m1, 16},
+        { 1, bark_tab_l08_512, 30, tab.fcb08l  , 3, 6, tab.cb0808l0, tab.cb0808l1, 17}
+    },
+    512 , 12, tab.lsp08,   1, 5, 3, 3, tab.shape08  , 8, 28, 20, 6, 40
+};
+
+static const ModeTab mode_11_08 = {
+    {
+        { 8, bark_tab_s11_64,  10, tab.fcb11s  , 1, 5, tab.cb1108s0, tab.cb1108s1, 29},
+        { 2, bark_tab_m11_256, 20, tab.fcb11m  , 2, 5, tab.cb1108m0, tab.cb1108m1, 24},
+        { 1, bark_tab_l11_512, 30, tab.fcb11l  , 3, 6, tab.cb1108l0, tab.cb1108l1, 27}
+    },
+    512 , 16, tab.lsp11,   1, 6, 4, 3, tab.shape11  , 9, 36, 30, 7, 90
+};
+
+static const ModeTab mode_11_10 = {
+    {
+        { 8, bark_tab_s11_64,  10, tab.fcb11s  , 1, 5, tab.cb1110s0, tab.cb1110s1, 21},
+        { 2, bark_tab_m11_256, 20, tab.fcb11m  , 2, 5, tab.cb1110m0, tab.cb1110m1, 18},
+        { 1, bark_tab_l11_512, 30, tab.fcb11l  , 3, 6, tab.cb1110l0, tab.cb1110l1, 20}
+    },
+    512 , 16, tab.lsp11,   1, 6, 4, 3, tab.shape11  , 9, 36, 30, 7, 90
+};
+
+static const ModeTab mode_16_16 = {
+    {
+        { 8, bark_tab_s16_128, 10, tab.fcb16s  , 1, 5, tab.cb1616s0, tab.cb1616s1, 16},
+        { 2, bark_tab_m16_512, 20, tab.fcb16m  , 2, 5, tab.cb1616m0, tab.cb1616m1, 15},
+        { 1, bark_tab_l16_1024,30, tab.fcb16l  , 3, 6, tab.cb1616l0, tab.cb1616l1, 16}
+    },
+    1024, 16, tab.lsp16,   1, 6, 4, 3, tab.shape16  , 9, 56, 60, 7, 180
+};
+
+static const ModeTab mode_22_20 = {
+    {
+        { 8, bark_tab_s22_128, 10, tab.fcb22s_1, 1, 6, tab.cb2220s0, tab.cb2220s1, 18},
+        { 2, bark_tab_m22_512, 20, tab.fcb22m_1, 2, 6, tab.cb2220m0, tab.cb2220m1, 17},
+        { 1, bark_tab_l22_1024,32, tab.fcb22l_1, 4, 6, tab.cb2220l0, tab.cb2220l1, 18}
+    },
+    1024, 16, tab.lsp22_1, 1, 6, 4, 3, tab.shape22_1, 9, 56, 36, 7, 144
+};
+
+static const ModeTab mode_22_24 = {
+    {
+        { 8, bark_tab_s22_128, 10, tab.fcb22s_1, 1, 6, tab.cb2224s0, tab.cb2224s1, 15},
+        { 2, bark_tab_m22_512, 20, tab.fcb22m_1, 2, 6, tab.cb2224m0, tab.cb2224m1, 14},
+        { 1, bark_tab_l22_1024,32, tab.fcb22l_1, 4, 6, tab.cb2224l0, tab.cb2224l1, 15}
+    },
+    1024, 16, tab.lsp22_1, 1, 6, 4, 3, tab.shape22_1, 9, 56, 36, 7, 144
+};
+
+static const ModeTab mode_22_32 = {
+    {
+        { 4, bark_tab_s22_128, 10, tab.fcb22s_2, 1, 6, tab.cb2232s0, tab.cb2232s1, 11},
+        { 2, bark_tab_m22_256, 20, tab.fcb22m_2, 2, 6, tab.cb2232m0, tab.cb2232m1, 11},
+        { 1, bark_tab_l22_512, 32, tab.fcb22l_2, 4, 6, tab.cb2232l0, tab.cb2232l1, 12}
+    },
+    512 , 16, tab.lsp22_2, 1, 6, 4, 4, tab.shape22_2, 9, 56, 36, 7, 72
+};
+
+static const ModeTab mode_44_40 = {
+    {
+        {16, bark_tab_s44_128, 10, tab.fcb44s  , 1, 6, tab.cb4440s0, tab.cb4440s1, 18},
+        { 4, bark_tab_m44_512, 20, tab.fcb44m  , 2, 6, tab.cb4440m0, tab.cb4440m1, 17},
+        { 1, bark_tab_l44_2048,40, tab.fcb44l  , 4, 6, tab.cb4440l0, tab.cb4440l1, 17}
+    },
+    2048, 20, tab.lsp44,   1, 6, 4, 4, tab.shape44  , 9, 84, 54, 7, 432
+};
+
+static const ModeTab mode_44_48 = {
+    {
+        {16, bark_tab_s44_128, 10, tab.fcb44s  , 1, 6, tab.cb4448s0, tab.cb4448s1, 15},
+        { 4, bark_tab_m44_512, 20, tab.fcb44m  , 2, 6, tab.cb4448m0, tab.cb4448m1, 14},
+        { 1, bark_tab_l44_2048,40, tab.fcb44l  , 4, 6, tab.cb4448l0, tab.cb4448l1, 14}
+    },
+    2048, 20, tab.lsp44,   1, 6, 4, 4, tab.shape44  , 9, 84, 54, 7, 432
+};
+
+typedef struct TwinContext {
+    AVCodecContext *avctx;
+    DSPContext      dsp;
+    MDCTContext mdct_ctx[3];
+
+    const ModeTab *mtab;
+
+    // history
+    float lsp_hist[2][20];           ///< LSP coefficients of the last frame
+    float bark_hist[3][2][40];       ///< BSE coefficients of last frame
+
+    // bitstream parameters
+    int16_t permut[4][4096];
+    uint8_t length[4][2];            ///< main codebook stride
+    uint8_t length_change[4];
+    uint8_t bits_main_spec[2][4][2]; ///< bits for the main codebook
+    int bits_main_spec_change[4];
+    int n_div[4];
+
+    float *spectrum;
+    float *curr_frame;               ///< non-interleaved output
+    float *prev_frame;               ///< non-interleaved previous frame
+    int last_block_pos[2];
+
+    float *cos_tabs[3];
+
+    // scratch buffers
+    float *tmp_buf;
+} TwinContext;
+
+#define PPC_SHAPE_CB_SIZE 64
+#define SUB_AMP_MAX       4500.0
+#define MULAW_MU          100.0
+#define GAIN_BITS         8
+#define AMP_MAX           13000.0
+#define SUB_GAIN_BITS     5
+#define WINDOW_TYPE_BITS  4
+#define PGAIN_MU          200
+
+/** @note not speed critical, hence not optimized */
+static void memset_float(float *buf, float val, int size)
+{
+    while (size--)
+        *buf++ = val;
+}
+
+/**
+ * Evaluate a single LPC amplitude spectrum envelope coefficient from the line
+ * spectrum pairs.
+ *
+ * @param lsp a vector of the cosinus of the LSP values
+ * @param cos_val cos(PI*i/N) where i is the index of the LPC amplitude
+ * @param order the order of the LSP (and the size of the *lsp buffer). Must
+ *        be a multiple of four.
+ * @return the LPC value
+ *
+ * @todo reuse code from vorbis_dec.c: vorbis_floor0_decode
+ */
+static float eval_lpc_spectrum(const float *lsp, float cos_val, int order)
+{
+    int j;
+    float p = 0.5f;
+    float q = 0.5f;
+    float two_cos_w = 2.0f*cos_val;
+
+    for (j=0; j+1 < order; j += 2*2) {
+        // Unroll the loop once since order is a multiple of four
+        q *= lsp[j  ] - two_cos_w;
+        p *= lsp[j+1] - two_cos_w;
+
+        q *= lsp[j+2] - two_cos_w;
+        p *= lsp[j+3] - two_cos_w;
+    }
+
+    p *= p * (2.0f - two_cos_w);
+    q *= q * (2.0f + two_cos_w);
+
+    return 0.5 / (p + q);
+}
+
+/**
+ * Evaluates the LPC amplitude spectrum envelope from the line spectrum pairs.
+ */
+static void eval_lpcenv(TwinContext *tctx, const float *cos_vals, float *lpc)
+{
+    int i;
+    const ModeTab *mtab = tctx->mtab;
+    int size_s = mtab->size / mtab->fmode[FT_SHORT].sub;
+
+    for (i=0; i < size_s/2; i++) {
+        float cos_i = tctx->cos_tabs[0][i];
+        lpc[i]          = eval_lpc_spectrum(cos_vals,  cos_i, mtab->n_lsp);
+        lpc[size_s-i-1] = eval_lpc_spectrum(cos_vals, -cos_i, mtab->n_lsp);
+    }
+}
+
+static void interpolate(float *out, float v1, float v2, int size)
+{
+    int i;
+    float step = (v1 - v2)/(size + 1);
+
+    for (i=0; i < size; i++) {
+        v2 += step;
+        out[i] = v2;
+    }
+}
+
+static inline float get_cos(int idx, int part, const float *cos_tab, int size)
+{
+    return part ? -cos_tab[size - idx - 1] :
+                   cos_tab[       idx    ];
+}
+
+/**
+ * Evaluates the LPC amplitude spectrum envelope from the line spectrum pairs.
+ * Probably for speed reasons, the coefficients are evaluated as
+ * siiiibiiiisiiiibiiiisiiiibiiiisiiiibiiiis ...
+ * where s is an evaluated value, i is a value interpolated from the others
+ * and b might be either calculated or interpolated, depending on an
+ * unexplained condition.
+ *
+ * @param step the size of a block "siiiibiiii"
+ * @param in the cosinus of the LSP data
+ * @param part is 0 for 0...PI (positive cossinus values) and 1 for PI...2PI
+          (negative cossinus values)
+ * @param size the size of the whole output
+ */
+static inline void eval_lpcenv_or_interp(TwinContext *tctx,
+                                         enum FrameType ftype,
+                                         float *out, const float *in,
+                                         int size, int step, int part)
+{
+    int i;
+    const ModeTab *mtab = tctx->mtab;
+    const float *cos_tab = tctx->cos_tabs[ftype];
+
+    // Fill the 's'
+    for (i=0; i < size; i += step)
+        out[i] =
+            eval_lpc_spectrum(in,
+                              get_cos(i, part, cos_tab, size),
+                              mtab->n_lsp);
+
+    // Fill the 'iiiibiiii'
+    for (i=step; i <= size - 2*step; i += step) {
+        if (out[i + step] + out[i - step] >  1.95*out[i] ||
+            out[i + step]                 >=  out[i - step]) {
+            interpolate(out + i - step + 1, out[i], out[i-step], step - 1);
+        } else {
+            out[i - step/2] =
+                eval_lpc_spectrum(in,
+                                  get_cos(i-step/2, part, cos_tab, size),
+                                  mtab->n_lsp);
+            interpolate(out + i - step   + 1, out[i-step/2], out[i-step  ], step/2 - 1);
+            interpolate(out + i - step/2 + 1, out[i       ], out[i-step/2], step/2 - 1);
+        }
+    }
+
+    interpolate(out + size - 2*step + 1, out[size-step], out[size - 2*step], step - 1);
+}
+
+static void eval_lpcenv_2parts(TwinContext *tctx, enum FrameType ftype,
+                               const float *buf, float *lpc,
+                               int size, int step)
+{
+    eval_lpcenv_or_interp(tctx, ftype, lpc         , buf, size/2,   step, 0);
+    eval_lpcenv_or_interp(tctx, ftype, lpc + size/2, buf, size/2, 2*step, 1);
+
+    interpolate(lpc+size/2-step+1, lpc[size/2], lpc[size/2-step], step);
+
+    memset_float(lpc + size - 2*step + 1, lpc[size - 2*step], 2*step - 1);
+}
+
+/**
+ * Inverse quantization. Read CB coefficients for cb1 and cb2 from the
+ * bitstream, sum the corresponding vectors and write the result to *out
+ * after permutation.
+ */
+static void dequant(TwinContext *tctx, GetBitContext *gb, float *out,
+                    enum FrameType ftype,
+                    const int16_t *cb0, const int16_t *cb1, int cb_len)
+{
+    int pos = 0;
+    int i, j;
+
+    for (i=0; i < tctx->n_div[ftype]; i++) {
+        int tmp0, tmp1;
+        int sign0 = 1;
+        int sign1 = 1;
+        const int16_t *tab0, *tab1;
+        int length = tctx->length[ftype][i >= tctx->length_change[ftype]];
+        int bitstream_second_part = (i >= tctx->bits_main_spec_change[ftype]);
+
+        int bits = tctx->bits_main_spec[0][ftype][bitstream_second_part];
+        if (bits == 7) {
+            if (get_bits1(gb))
+                sign0 = -1;
+            bits = 6;
+        }
+        tmp0 = get_bits(gb, bits);
+
+        bits = tctx->bits_main_spec[1][ftype][bitstream_second_part];
+
+        if (bits == 7) {
+            if (get_bits1(gb))
+                sign1 = -1;
+
+            bits = 6;
+        }
+        tmp1 = get_bits(gb, bits);
+
+        tab0 = cb0 + tmp0*cb_len;
+        tab1 = cb1 + tmp1*cb_len;
+
+        for (j=0; j < length; j++)
+            out[tctx->permut[ftype][pos+j]] = sign0*tab0[j] + sign1*tab1[j];
+
+        pos += length;
+    }
+
+}
+
+static inline float mulawinv(float y, float clip, float mu)
+{
+    y = av_clipf(y/clip, -1, 1);
+    return clip * FFSIGN(y) * (exp(log(1+mu) * fabs(y)) - 1) / mu;
+}
+
+/**
+ * Evaluate a*b/400 rounded to the nearest integer. When, for example,
+ * a*b == 200 and the nearest integer is ill-defined, use a table to emulate
+ * the following broken float-based implementation used by the binary decoder:
+ *
+ * \code
+ * static int very_broken_op(int a, int b)
+ * {
+ *    static float test; // Ugh, force gcc to do the division first...
+ *
+ *    test = a/400.;
+ *    return b * test +  0.5;
+ * }
+ * \endcode
+ *
+ * @note if this function is replaced by just ROUNDED_DIV(a*b,400.), the stddev
+ * between the original file (before encoding with Yamaha encoder) and the
+ * decoded output increases, which leads one to believe that the encoder expects
+ * exactly this broken calculation.
+ */
+static int very_broken_op(int a, int b)
+{
+    int x = a*b + 200;
+    int size;
+    const uint8_t *rtab;
+
+    if (x%400 || b%5)
+        return x/400;
+
+    x /= 400;
+
+    size = tabs[b/5].size;
+    rtab = tabs[b/5].tab;
+    return x - rtab[size*av_log2(2*(x - 1)/size)+(x - 1)%size];
+}
+
+/**
+ * Sum to data a periodic peak of a given period, width and shape.
+ *
+ * @param period the period of the peak divised by 400.0
+ */
+static void add_peak(int period, int width, const float *shape,
+                     float ppc_gain, float *speech, int len)
+{
+    int i, j;
+
+    const float *shape_end = shape + len;
+    int center;
+
+    // First peak centered around zero
+    for (i=0; i < width/2; i++)
+        speech[i] += ppc_gain * *shape++;
+
+    for (i=1; i < ROUNDED_DIV(len,width) ; i++) {
+        center = very_broken_op(period, i);
+        for (j=-width/2; j < (width+1)/2; j++)
+            speech[j+center] += ppc_gain * *shape++;
+    }
+
+    // For the last block, be careful not to go beyond the end of the buffer
+    center = very_broken_op(period, i);
+    for (j=-width/2; j < (width+1)/2 && shape < shape_end; j++)
+        speech[j+center] += ppc_gain * *shape++;
+}
+
+static void decode_ppc(TwinContext *tctx, int period_coef, const float *shape,
+                       float ppc_gain, float *speech)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int isampf = tctx->avctx->sample_rate/1000;
+    int ibps = tctx->avctx->bit_rate/(1000 * tctx->avctx->channels);
+    int min_period = ROUNDED_DIV(  40*2*mtab->size, isampf);
+    int max_period = ROUNDED_DIV(6*40*2*mtab->size, isampf);
+    int period_range = max_period - min_period;
+
+    // This is actually the period multiplied by 400. It is just linearly coded
+    // between its maximum and minimum value.
+    int period = min_period +
+        ROUNDED_DIV(period_coef*period_range, (1 << mtab->ppc_period_bit) - 1);
+    int width;
+
+    if (isampf == 22 && ibps == 32) {
+        // For some unknown reason, NTT decided to code this case differently...
+        width = ROUNDED_DIV((period + 800)* mtab->peak_per2wid, 400*mtab->size);
+    } else
+        width =             (period      )* mtab->peak_per2wid/(400*mtab->size);
+
+    add_peak(period, width, shape, ppc_gain, speech, mtab->ppc_shape_len);
+}
+
+static void dec_gain(TwinContext *tctx, GetBitContext *gb, enum FrameType ftype,
+                     float *out)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int i, j;
+    int sub = mtab->fmode[ftype].sub;
+    float step     = AMP_MAX     / ((1 <<     GAIN_BITS) - 1);
+    float sub_step = SUB_AMP_MAX / ((1 << SUB_GAIN_BITS) - 1);
+
+    if (ftype == FT_LONG) {
+        for (i=0; i < tctx->avctx->channels; i++)
+            out[i] = (1./(1<<13)) *
+                mulawinv(step * 0.5 + step * get_bits(gb, GAIN_BITS),
+                         AMP_MAX, MULAW_MU);
+    } else {
+        for (i=0; i < tctx->avctx->channels; i++) {
+            float val = (1./(1<<23)) *
+                mulawinv(step * 0.5 + step * get_bits(gb, GAIN_BITS),
+                         AMP_MAX, MULAW_MU);
+
+            for (j=0; j < sub; j++) {
+                out[i*sub + j] =
+                    val*mulawinv(sub_step* 0.5 +
+                                 sub_step* get_bits(gb, SUB_GAIN_BITS),
+                                 SUB_AMP_MAX, MULAW_MU);
+            }
+        }
+    }
+}
+
+/**
+ * Rearrange the LSP coefficients so that they have a minimum distance of
+ * min_dist. This function does it exactly as described in section of 3.2.4
+ * of the G.729 specification (but interestingly is different from what the
+ * reference decoder actually does).
+ */
+static void rearrange_lsp(int order, float *lsp, float min_dist)
+{
+    int i;
+    float min_dist2 = min_dist * 0.5;
+    for (i=1; i < order; i++)
+        if (lsp[i] - lsp[i-1] < min_dist) {
+            float avg = (lsp[i] + lsp[i-1]) * 0.5;
+
+            lsp[i-1] = avg - min_dist2;
+            lsp[i  ] = avg + min_dist2;
+        }
+}
+
+static void bubblesort(float *lsp, int lp_order)
+{
+    int i,j;
+
+    /* sort lsp in ascending order. float bubble agorithm,
+       O(n) if data already sorted, O(n^2) - otherwise */
+    for (i=0; i < lp_order - 1; i++)
+        for (j=i; j >= 0 && lsp[j] > lsp[j+1]; j--)
+            FFSWAP(float, lsp[j], lsp[j+1]);
+}
+
+static void decode_lsp(TwinContext *tctx, int lpc_idx1, uint8_t *lpc_idx2,
+                       int lpc_hist_idx, float *lsp, float *hist)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int i, j;
+
+    const float *cb  =  mtab->lspcodebook;
+    const float *cb2 =  cb  + (1 << mtab->lsp_bit1)*mtab->n_lsp;
+    const float *cb3 =  cb2 + (1 << mtab->lsp_bit2)*mtab->n_lsp;
+
+    const int8_t funny_rounding[4] = {
+        -2,
+        mtab->lsp_split == 4 ? -2 : 1,
+        mtab->lsp_split == 4 ? -2 : 1,
+        0
+    };
+
+    j=0;
+    for (i=0; i < mtab->lsp_split; i++) {
+        int chunk_end = ((i + 1)*mtab->n_lsp + funny_rounding[i])/mtab->lsp_split;
+        for (; j < chunk_end; j++)
+            lsp[j] = cb [lpc_idx1    * mtab->n_lsp + j] +
+                     cb2[lpc_idx2[i] * mtab->n_lsp + j];
+    }
+
+    rearrange_lsp(mtab->n_lsp, lsp, 0.0001);
+
+    for (i=0; i < mtab->n_lsp; i++) {
+        float tmp1 = 1. -          cb3[lpc_hist_idx*mtab->n_lsp + i];
+        float tmp2 =     hist[i] * cb3[lpc_hist_idx*mtab->n_lsp + i];
+        hist[i] = lsp[i];
+        lsp[i]  = lsp[i] * tmp1 + tmp2;
+    }
+
+    rearrange_lsp(mtab->n_lsp, lsp, 0.0001);
+    rearrange_lsp(mtab->n_lsp, lsp, 0.000095);
+    bubblesort(lsp, mtab->n_lsp);
+}
+
+static void dec_lpc_spectrum_inv(TwinContext *tctx, float *lsp,
+                                 enum FrameType ftype, float *lpc)
+{
+    int i;
+    int size = tctx->mtab->size / tctx->mtab->fmode[ftype].sub;
+
+    for (i=0; i < tctx->mtab->n_lsp; i++)
+        lsp[i] =  2*cos(lsp[i]);
+
+    switch (ftype) {
+    case FT_LONG:
+        eval_lpcenv_2parts(tctx, ftype, lsp, lpc, size, 8);
+        break;
+    case FT_MEDIUM:
+        eval_lpcenv_2parts(tctx, ftype, lsp, lpc, size, 2);
+        break;
+    case FT_SHORT:
+        eval_lpcenv(tctx, lsp, lpc);
+        break;
+    }
+}
+
+static void imdct_and_window(TwinContext *tctx, enum FrameType ftype, int wtype,
+                            float *in, float *prev, int ch)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int bsize = mtab->size / mtab->fmode[ftype].sub;
+    int size  = mtab->size;
+    float *buf1 = tctx->tmp_buf;
+    int j;
+    int wsize; // Window size
+    float *out = tctx->curr_frame + 2*ch*mtab->size;
+    float *out2 = out;
+    float *prev_buf;
+    int first_wsize;
+
+    static const uint8_t wtype_to_wsize[]      = {0, 0, 2, 2, 2, 1, 0, 1, 1};
+    int types_sizes[] = {
+        mtab->size /    mtab->fmode[FT_LONG  ].sub,
+        mtab->size /    mtab->fmode[FT_MEDIUM].sub,
+        mtab->size / (2*mtab->fmode[FT_SHORT ].sub),
+    };
+
+    wsize = types_sizes[wtype_to_wsize[wtype]];
+    first_wsize = wsize;
+    prev_buf = prev + (size - bsize)/2;
+
+    for (j=0; j < mtab->fmode[ftype].sub; j++) {
+        int sub_wtype = ftype == FT_MEDIUM ? 8 : wtype;
+
+        if (!j && wtype == 4)
+            sub_wtype = 4;
+        else if (j == mtab->fmode[ftype].sub-1 && wtype == 7)
+            sub_wtype = 7;
+
+        wsize = types_sizes[wtype_to_wsize[sub_wtype]];
+
+        ff_imdct_half(&tctx->mdct_ctx[ftype], buf1 + bsize*j, in + bsize*j);
+
+        tctx->dsp.vector_fmul_window(out2,
+                                     prev_buf + (bsize-wsize)/2,
+                                     buf1 + bsize*j,
+                                     ff_sine_windows[av_log2(wsize) - 7],
+                                     0.0,
+                                     wsize/2);
+        out2 += wsize;
+
+        memcpy(out2, buf1 + bsize*j + wsize/2, (bsize - wsize/2)*sizeof(float));
+
+        out2 += ftype == FT_MEDIUM ? (bsize-wsize)/2 : bsize - wsize;
+
+        prev_buf = buf1 + bsize*j + bsize/2;
+    }
+
+    tctx->last_block_pos[ch] = (size + first_wsize)/2;
+}
+
+static void imdct_output(TwinContext *tctx, enum FrameType ftype, int wtype,
+                         float *out)
+{
+    const ModeTab *mtab = tctx->mtab;
+    float *prev_buf = tctx->prev_frame + tctx->last_block_pos[0];
+    int i, j;
+
+    for (i=0; i < tctx->avctx->channels; i++) {
+        imdct_and_window(tctx, ftype, wtype,
+                         tctx->spectrum + i*mtab->size,
+                         prev_buf + 2*i*mtab->size,
+                         i);
+    }
+
+    if (tctx->avctx->channels == 2) {
+        for (i=0; i < mtab->size - tctx->last_block_pos[0]; i++) {
+            float f1 = prev_buf[               i];
+            float f2 = prev_buf[2*mtab->size + i];
+            out[2*i    ] = f1 + f2;
+            out[2*i + 1] = f1 - f2;
+        }
+        for (j=0; i < mtab->size; j++,i++) {
+            float f1 = tctx->curr_frame[               j];
+            float f2 = tctx->curr_frame[2*mtab->size + j];
+            out[2*i    ] = f1 + f2;
+            out[2*i + 1] = f1 - f2;
+        }
+    } else {
+        memcpy(out, prev_buf,
+               (mtab->size - tctx->last_block_pos[0]) * sizeof(*out));
+
+        out +=  mtab->size - tctx->last_block_pos[0];
+
+        memcpy(out, tctx->curr_frame,
+               (tctx->last_block_pos[0]) * sizeof(*out));
+    }
+
+}
+
+static void dec_bark_env(TwinContext *tctx, const uint8_t *in, int use_hist,
+                         int ch, float *out, float gain, enum FrameType ftype)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int i,j;
+    float *hist = tctx->bark_hist[ftype][ch];
+    float val = ((const float []) {0.4, 0.35, 0.28})[ftype];
+    int bark_n_coef  = mtab->fmode[ftype].bark_n_coef;
+    int fw_cb_len = mtab->fmode[ftype].bark_env_size / bark_n_coef;
+    int idx = 0;
+
+    for (i=0; i < fw_cb_len; i++)
+        for (j=0; j < bark_n_coef; j++, idx++) {
+            float tmp2 =
+                mtab->fmode[ftype].bark_cb[fw_cb_len*in[j] + i] * (1./4096);
+            float st = use_hist ?
+                (1. - val) * tmp2 + val*hist[idx] + 1. : tmp2 + 1.;
+
+            hist[idx] = tmp2;
+            if (st < -1.) st = 1.;
+
+            memset_float(out, st * gain, mtab->fmode[ftype].bark_tab[idx]);
+            out += mtab->fmode[ftype].bark_tab[idx];
+        }
+
+}
+
+static void read_and_decode_spectrum(TwinContext *tctx, GetBitContext *gb,
+                                     float *out, enum FrameType ftype)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int channels = tctx->avctx->channels;
+    int sub = mtab->fmode[ftype].sub;
+    int block_size = mtab->size / sub;
+    float gain[channels*sub];
+    float ppc_shape[mtab->ppc_shape_len * channels * 4];
+    uint8_t bark1[channels][sub][mtab->fmode[ftype].bark_n_coef];
+    uint8_t bark_use_hist[channels][sub];
+
+    uint8_t lpc_idx1[channels];
+    uint8_t lpc_idx2[channels][tctx->mtab->lsp_split];
+    uint8_t lpc_hist_idx[channels];
+
+    int i, j, k;
+
+    dequant(tctx, gb, out, ftype,
+            mtab->fmode[ftype].cb0, mtab->fmode[ftype].cb1,
+            mtab->fmode[ftype].cb_len_read);
+
+    for (i=0; i < channels; i++)
+        for (j=0; j < sub; j++)
+            for (k=0; k < mtab->fmode[ftype].bark_n_coef; k++)
+                bark1[i][j][k] =
+                    get_bits(gb, mtab->fmode[ftype].bark_n_bit);
+
+    for (i=0; i < channels; i++)
+        for (j=0; j < sub; j++)
+            bark_use_hist[i][j] = get_bits1(gb);
+
+    dec_gain(tctx, gb, ftype, gain);
+
+    for (i=0; i < channels; i++) {
+        lpc_hist_idx[i] = get_bits(gb, tctx->mtab->lsp_bit0);
+        lpc_idx1    [i] = get_bits(gb, tctx->mtab->lsp_bit1);
+
+        for (j=0; j < tctx->mtab->lsp_split; j++)
+            lpc_idx2[i][j] = get_bits(gb, tctx->mtab->lsp_bit2);
+    }
+
+    if (ftype == FT_LONG) {
+        int cb_len_p = (tctx->n_div[3] + mtab->ppc_shape_len*channels - 1)/
+            tctx->n_div[3];
+        dequant(tctx, gb, ppc_shape, FT_PPC, mtab->ppc_shape_cb,
+                mtab->ppc_shape_cb + cb_len_p*PPC_SHAPE_CB_SIZE, cb_len_p);
+    }
+
+    for (i=0; i < channels; i++) {
+        float *chunk = out + mtab->size * i;
+        float lsp[tctx->mtab->n_lsp];
+
+        for (j=0; j < sub; j++) {
+            dec_bark_env(tctx, bark1[i][j], bark_use_hist[i][j], i,
+                         tctx->tmp_buf, gain[sub*i+j], ftype);
+
+            tctx->dsp.vector_fmul(chunk + block_size*j, tctx->tmp_buf,
+                                  block_size);
+
+        }
+
+        if (ftype == FT_LONG) {
+            float pgain_step = 25000. / ((1 << mtab->pgain_bit) - 1);
+            int p_coef = get_bits(gb, tctx->mtab->ppc_period_bit);
+            int g_coef = get_bits(gb, tctx->mtab->pgain_bit);
+            float v = 1./8192*
+                mulawinv(pgain_step*g_coef+ pgain_step/2, 25000., PGAIN_MU);
+
+            decode_ppc(tctx, p_coef, ppc_shape + i*mtab->ppc_shape_len, v,
+                       chunk);
+        }
+
+        decode_lsp(tctx, lpc_idx1[i], lpc_idx2[i], lpc_hist_idx[i], lsp,
+                   tctx->lsp_hist[i]);
+
+        dec_lpc_spectrum_inv(tctx, lsp, ftype, tctx->tmp_buf);
+
+        for (j=0; j < mtab->fmode[ftype].sub; j++) {
+            tctx->dsp.vector_fmul(chunk, tctx->tmp_buf, block_size);
+            chunk += block_size;
+        }
+    }
+}
+
+static int twin_decode_frame(AVCodecContext * avctx, void *data,
+                             int *data_size, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    int buf_size = avpkt->size;
+    TwinContext *tctx = avctx->priv_data;
+    GetBitContext gb;
+    const ModeTab *mtab = tctx->mtab;
+    float *out = data;
+    enum FrameType ftype;
+    int window_type;
+    int i;
+    static const enum FrameType wtype_to_ftype_table[] = {
+        FT_LONG,   FT_LONG, FT_SHORT, FT_LONG,
+        FT_MEDIUM, FT_LONG, FT_LONG,  FT_MEDIUM, FT_MEDIUM
+    };
+
+    if (buf_size*8 < avctx->bit_rate*mtab->size/avctx->sample_rate + 8) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Frame too small (%d bytes). Truncated file?\n", buf_size);
+        *data_size = 0;
+        return buf_size;
+    }
+
+    init_get_bits(&gb, buf, buf_size * 8);
+    skip_bits(&gb, get_bits(&gb, 8));
+    window_type = get_bits(&gb, WINDOW_TYPE_BITS);
+
+    if (window_type > 8) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid window type, broken sample?\n");
+        return -1;
+    }
+
+    ftype = wtype_to_ftype_table[window_type];
+
+    read_and_decode_spectrum(tctx, &gb, tctx->spectrum, ftype);
+
+    imdct_output(tctx, ftype, window_type, out);
+
+    FFSWAP(float*, tctx->curr_frame, tctx->prev_frame);
+
+    if (tctx->avctx->frame_number < 2) {
+        *data_size=0;
+        return buf_size;
+    }
+
+    for (i=0; i < avctx->channels * mtab->size; i++)
+        out[i] = av_clipf(out[i], -32700./(1<<15), 32700./(1<<15));
+
+    *data_size = mtab->size*avctx->channels*4;
+
+    return buf_size;
+}
+
+/**
+ * Init IMDCT and windowing tables
+ */
+static av_cold void init_mdct_win(TwinContext *tctx)
+{
+    int i,j;
+    const ModeTab *mtab = tctx->mtab;
+    int size_s = mtab->size / mtab->fmode[FT_SHORT].sub;
+    int size_m = mtab->size / mtab->fmode[FT_MEDIUM].sub;
+    int channels = tctx->avctx->channels;
+    float norm = channels == 1 ? 2. : 1.;
+
+    for (i=0; i < 3; i++) {
+        int bsize = tctx->mtab->size/tctx->mtab->fmode[i].sub;
+        ff_mdct_init(&tctx->mdct_ctx[i], av_log2(bsize) + 1, 1,
+                     -sqrt(norm/bsize) / (1<<15));
+    }
+
+    tctx->tmp_buf  = av_malloc(mtab->size            * sizeof(*tctx->tmp_buf));
+
+    tctx->spectrum  = av_malloc(2*mtab->size*channels*sizeof(float));
+    tctx->curr_frame = av_malloc(2*mtab->size*channels*sizeof(float));
+    tctx->prev_frame  = av_malloc(2*mtab->size*channels*sizeof(float));
+
+    for(i=0; i < 3; i++) {
+        int m = 4*mtab->size/mtab->fmode[i].sub;
+        double freq = 2*M_PI/m;
+        tctx->cos_tabs[i] = av_malloc((m/4)*sizeof(*tctx->cos_tabs));
+
+        for (j=0; j <= m/8; j++)
+            tctx->cos_tabs[i][j] = cos((2*j + 1)*freq);
+        for (j=1; j <  m/8; j++)
+            tctx->cos_tabs[i][m/4-j] = tctx->cos_tabs[i][j];
+    }
+
+
+    ff_sine_window_init(ff_sine_windows[av_log2(size_m)     - 7], size_m  );
+    ff_sine_window_init(ff_sine_windows[av_log2(size_s/2)   - 7], size_s/2);
+    ff_sine_window_init(ff_sine_windows[av_log2(mtab->size) - 7], mtab->size);
+}
+
+/**
+ * Interpret the data as if it were a num_blocks x line_len[0] matrix and for
+ * each line do a cyclic permutation, i.e.
+ * abcdefghijklm -> defghijklmabc
+ * where the amount to be shifted is evaluated depending on the column.
+ */
+static void permutate_in_line(int16_t *tab, int num_vect, int num_blocks,
+                              int block_size,
+                              const uint8_t line_len[2], int length_div,
+                              enum FrameType ftype)
+
+{
+    int i,j;
+
+    for (i=0; i < line_len[0]; i++) {
+        int shift;
+
+        if (num_blocks == 1 ||
+            (ftype == FT_LONG && num_vect % num_blocks) ||
+            (ftype != FT_LONG && num_vect & 1         ) ||
+            i == line_len[1]) {
+            shift = 0;
+        } else if (ftype == FT_LONG) {
+            shift = i;
+        } else
+            shift = i*i;
+
+        for (j=0; j < num_vect && (j+num_vect*i < block_size*num_blocks); j++)
+            tab[i*num_vect+j] = i*num_vect + (j + shift) % num_vect;
+    }
+}
+
+/**
+ * Interpret the input data as in the following table:
+ *
+ * \verbatim
+ *
+ * abcdefgh
+ * ijklmnop
+ * qrstuvw
+ * x123456
+ *
+ * \endverbatim
+ *
+ * and transpose it, giving the output
+ * aiqxbjr1cks2dlt3emu4fvn5gow6hp
+ */
+static void transpose_perm(int16_t *out, int16_t *in, int num_vect,
+                           const uint8_t line_len[2], int length_div)
+{
+    int i,j;
+    int cont= 0;
+    for (i=0; i < num_vect; i++)
+        for (j=0; j < line_len[i >= length_div]; j++)
+            out[cont++] = in[j*num_vect + i];
+}
+
+static void linear_perm(int16_t *out, int16_t *in, int n_blocks, int size)
+{
+    int block_size = size/n_blocks;
+    int i;
+
+    for (i=0; i < size; i++)
+        out[i] = block_size * (in[i] % n_blocks) + in[i] / n_blocks;
+}
+
+static av_cold void construct_perm_table(TwinContext *tctx,enum FrameType ftype)
+{
+    int block_size;
+    const ModeTab *mtab = tctx->mtab;
+    int size = tctx->avctx->channels*mtab->fmode[ftype].sub;
+    int16_t *tmp_perm = (int16_t *) tctx->tmp_buf;
+
+    if (ftype == FT_PPC) {
+        size  = tctx->avctx->channels;
+        block_size = mtab->ppc_shape_len;
+    } else
+        block_size = mtab->size / mtab->fmode[ftype].sub;
+
+    permutate_in_line(tmp_perm, tctx->n_div[ftype], size,
+                      block_size, tctx->length[ftype],
+                      tctx->length_change[ftype], ftype);
+
+    transpose_perm(tctx->permut[ftype], tmp_perm, tctx->n_div[ftype],
+                   tctx->length[ftype], tctx->length_change[ftype]);
+
+    linear_perm(tctx->permut[ftype], tctx->permut[ftype], size,
+                size*block_size);
+}
+
+static av_cold void init_bitstream_params(TwinContext *tctx)
+{
+    const ModeTab *mtab = tctx->mtab;
+    int n_ch = tctx->avctx->channels;
+    int total_fr_bits = tctx->avctx->bit_rate*mtab->size/
+                             tctx->avctx->sample_rate;
+
+    int lsp_bits_per_block = n_ch*(mtab->lsp_bit0 + mtab->lsp_bit1 +
+                                   mtab->lsp_split*mtab->lsp_bit2);
+
+    int ppc_bits = n_ch*(mtab->pgain_bit + mtab->ppc_shape_bit +
+                         mtab->ppc_period_bit);
+
+    int bsize_no_main_cb[3];
+    int bse_bits[3];
+    int i;
+
+    for (i=0; i < 3; i++)
+        // +1 for history usage switch
+        bse_bits[i] = n_ch *
+            (mtab->fmode[i].bark_n_coef * mtab->fmode[i].bark_n_bit + 1);
+
+    bsize_no_main_cb[2] = bse_bits[2] + lsp_bits_per_block + ppc_bits +
+                          WINDOW_TYPE_BITS + n_ch*GAIN_BITS;
+
+    for (i=0; i < 2; i++)
+        bsize_no_main_cb[i] =
+            lsp_bits_per_block + n_ch*GAIN_BITS + WINDOW_TYPE_BITS +
+            mtab->fmode[i].sub*(bse_bits[i] + n_ch*SUB_GAIN_BITS);
+
+    // The remaining bits are all used for the main spectrum coefficients
+    for (i=0; i < 4; i++) {
+        int bit_size;
+        int vect_size;
+        int rounded_up, rounded_down, num_rounded_down, num_rounded_up;
+        if (i == 3) {
+            bit_size  = n_ch * mtab->ppc_shape_bit;
+            vect_size = n_ch * mtab->ppc_shape_len;
+        } else {
+            bit_size = total_fr_bits - bsize_no_main_cb[i];
+            vect_size = n_ch * mtab->size;
+        }
+
+        tctx->n_div[i] = (bit_size + 13) / 14;
+
+        rounded_up   = (bit_size + tctx->n_div[i] - 1)/tctx->n_div[i];
+        rounded_down = (bit_size           )/tctx->n_div[i];
+        num_rounded_down = rounded_up * tctx->n_div[i] - bit_size;
+        num_rounded_up = tctx->n_div[i] - num_rounded_down;
+        tctx->bits_main_spec[0][i][0] = (rounded_up   + 1)/2;
+        tctx->bits_main_spec[1][i][0] = (rounded_up      )/2;
+        tctx->bits_main_spec[0][i][1] = (rounded_down + 1)/2;
+        tctx->bits_main_spec[1][i][1] = (rounded_down    )/2;
+        tctx->bits_main_spec_change[i] = num_rounded_up;
+
+        rounded_up   = (vect_size + tctx->n_div[i] - 1)/tctx->n_div[i];
+        rounded_down = (vect_size                     )/tctx->n_div[i];
+        num_rounded_down = rounded_up * tctx->n_div[i] - vect_size;
+        num_rounded_up = tctx->n_div[i] - num_rounded_down;
+        tctx->length[i][0] = rounded_up;
+        tctx->length[i][1] = rounded_down;
+        tctx->length_change[i] = num_rounded_up;
+    }
+
+    for (i=0; i < 4; i++)
+        construct_perm_table(tctx, i);
+}
+
+static av_cold int twin_decode_init(AVCodecContext *avctx)
+{
+    TwinContext *tctx = avctx->priv_data;
+    int isampf = avctx->sample_rate/1000;
+    int ibps = avctx->bit_rate/(1000 * avctx->channels);
+
+    tctx->avctx       = avctx;
+    avctx->sample_fmt = SAMPLE_FMT_FLT;
+
+    if (avctx->channels > 2) {
+        av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %i\n",
+               avctx->channels);
+        return -1;
+    }
+
+    switch ((isampf << 8) +  ibps) {
+    case (8 <<8) +  8: tctx->mtab = &mode_08_08; break;
+    case (11<<8) +  8: tctx->mtab = &mode_11_08; break;
+    case (11<<8) + 10: tctx->mtab = &mode_11_10; break;
+    case (16<<8) + 16: tctx->mtab = &mode_16_16; break;
+    case (22<<8) + 20: tctx->mtab = &mode_22_20; break;
+    case (22<<8) + 24: tctx->mtab = &mode_22_24; break;
+    case (22<<8) + 32: tctx->mtab = &mode_22_32; break;
+    case (44<<8) + 40: tctx->mtab = &mode_44_40; break;
+    case (44<<8) + 48: tctx->mtab = &mode_44_48; break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "This version does not support %d kHz - %d kbit/s/ch mode.\n", isampf, isampf);
+        return -1;
+    }
+
+    dsputil_init(&tctx->dsp, avctx);
+    init_mdct_win(tctx);
+    init_bitstream_params(tctx);
+
+    memset_float(tctx->bark_hist[0][0], 0.1, FF_ARRAY_ELEMS(tctx->bark_hist));
+
+    return 0;
+}
+
+static av_cold int twin_decode_close(AVCodecContext *avctx)
+{
+    TwinContext *tctx = avctx->priv_data;
+    int i;
+
+    for (i=0; i < 3; i++) {
+        ff_mdct_end(&tctx->mdct_ctx[i]);
+        av_free(tctx->cos_tabs[i]);
+    }
+
+
+    av_free(tctx->curr_frame);
+    av_free(tctx->spectrum);
+    av_free(tctx->prev_frame);
+    av_free(tctx->tmp_buf);
+
+    return 0;
+}
+
+AVCodec twinvq_decoder =
+{
+    "twinvq",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_TWINVQ,
+    sizeof(TwinContext),
+    twin_decode_init,
+    NULL,
+    twin_decode_close,
+    twin_decode_frame,
+    .long_name = NULL_IF_CONFIG_SMALL("VQF TwinVQ"),
+};