libavcodec/metasound.c - play-games/ffmpeg - Git at Google


            
            /*

            
             * Voxware MetaSound decoder

            
             * Copyright (c) 2013 Konstantin Shishkov

            
             * based on 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 <inttypes.h>

            
            #include <math.h>

            
            #include <stdint.h>


            #include "libavutil/channel_layout.h"


            #define BITSTREAM_READER_LE

            
            #include "avcodec.h"

            
            #include "codec_internal.h"

            
            #include "get_bits.h"


            #include "twinvq.h"

            
            #include "metasound_data.h"


            static void add_peak(float period, int width, const float *shape,

            
                                 float ppc_gain, float *speech, int len)

            
            {

            
                int i, j, center;

            
                const float *shape_end = shape + len;


                // 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 = (int)(i * period + 0.5);

            
                    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 = (int)(i * period + 0.5);

            
                for (j = -width / 2; j < (width + 1) / 2 && shape < shape_end; j++)

            
                    speech[j + center] += ppc_gain * *shape++;

            
            }


            static void decode_ppc(TwinVQContext *tctx, int period_coef, int g_coef,

            
                                   const float *shape, float *speech)

            
            {

            
                const TwinVQModeTab *mtab = tctx->mtab;

            
                int channels     = tctx->avctx->ch_layout.nb_channels;

            
                int isampf       = tctx->avctx->sample_rate / 1000;

            
                int ibps         = tctx->avctx->bit_rate / (1000 * channels);

            
                int width;


                float ratio = (float)mtab->size / isampf;

            
                float min_period, max_period, period_range, period;

            
                float some_mult;


                float pgain_base, pgain_step, ppc_gain;


                if (channels == 1) {

            
                    min_period = log2(ratio * 0.2);

            
                    max_period = min_period + log2(6);

            
                } else {

            
                    min_period = (int)(ratio * 0.2 * 400     + 0.5) / 400.0;

            
                    max_period = (int)(ratio * 0.2 * 400 * 6 + 0.5) / 400.0;

            
                }

            
                period_range = max_period - min_period;

            
                period       = min_period + period_coef * period_range /

            
                               ((1 << mtab->ppc_period_bit) - 1);

            
                if (channels == 1)

            
                    period = powf(2.0, period);

            
                else

            
                    period = (int)(period * 400 + 0.5) / 400.0;


                switch (isampf) {

            
                case  8: some_mult = 2.0; break;

            
                case 11: some_mult = 3.0; break;

            
                case 16: some_mult = 3.0; break;

            
                case 22: some_mult = ibps == 32 ? 2.0 : 4.0; break;

            
                case 44: some_mult = 8.0; break;

            
                default: some_mult = 4.0;

            
                }


                width = (int)(some_mult / (mtab->size / period) * mtab->ppc_shape_len);

            
                if (isampf == 22 && ibps == 32)

            
                    width = (int)((2.0 / period + 1) * width + 0.5);


                pgain_base = channels == 2 ? 25000.0 : 20000.0;

            
                pgain_step = pgain_base / ((1 << mtab->pgain_bit) - 1);

            
                ppc_gain   = 1.0 / 8192 *

            
                             twinvq_mulawinv(pgain_step * g_coef + pgain_step / 2,

            
                                             pgain_base, TWINVQ_PGAIN_MU);


                add_peak(period, width, shape, ppc_gain, speech, mtab->ppc_shape_len);

            
            }


            static void dec_bark_env(TwinVQContext *tctx, const uint8_t *in, int use_hist,

            
                                     int ch, float *out, float gain,

            
                                     enum TwinVQFrameType ftype)

            
            {

            
                const TwinVQModeTab *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;

            
                int channels    = tctx->avctx->ch_layout.nb_channels;


                if (channels == 1)

            
                    val = 0.5;

            
                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] *

            
                                     (1.0 / 2048);

            
                        float st;


                        if (channels == 1)

            
                            st = use_hist ?

            
                                tmp2 + val * hist[idx] + 1.0 : tmp2 + 1.0;

            
                        else

            
                            st = use_hist ? (1.0 - val) * tmp2 + val * hist[idx] + 1.0

            
                                          : tmp2 + 1.0;


                        hist[idx] = tmp2;

            
                        if (st < 0.1)

            
                            st = 0.1;


                        twinvq_memset_float(out, st * gain,

            
                                            mtab->fmode[ftype].bark_tab[idx]);

            
                        out += mtab->fmode[ftype].bark_tab[idx];

            
                    }

            
            }


            static void read_cb_data(TwinVQContext *tctx, GetBitContext *gb,

            
                                     uint8_t *dst, enum TwinVQFrameType ftype)

            
            {

            
                int i;


                for (i = 0; i < tctx->n_div[ftype]; i++) {

            
                    int bs_second_part = (i >= tctx->bits_main_spec_change[ftype]);


                    *dst++ = get_bits(gb, tctx->bits_main_spec[0][ftype][bs_second_part]);

            
                    *dst++ = get_bits(gb, tctx->bits_main_spec[1][ftype][bs_second_part]);

            
                }

            
            }


            static int metasound_read_bitstream(AVCodecContext *avctx, TwinVQContext *tctx,

            
                                                const uint8_t *buf, int buf_size)

            
            {

            
                TwinVQFrameData     *bits;

            
                const TwinVQModeTab *mtab = tctx->mtab;

            
                int channels              = tctx->avctx->ch_layout.nb_channels;

            
                int sub;

            
                GetBitContext gb;

            
                int i, j, k, ret;


                if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)

            
                    return ret;


                for (tctx->cur_frame = 0; tctx->cur_frame < tctx->frames_per_packet;

            
                     tctx->cur_frame++) {

            
                    bits = tctx->bits + tctx->cur_frame;


                    bits->window_type = get_bits(&gb, TWINVQ_WINDOW_TYPE_BITS);


                    if (bits->window_type > 8) {

            
                        av_log(avctx, AV_LOG_ERROR, "Invalid window type, broken sample?\n");

            
                        return AVERROR_INVALIDDATA;

            
                    }


                    bits->ftype = ff_twinvq_wtype_to_ftype_table[tctx->bits[tctx->cur_frame].window_type];


                    sub = mtab->fmode[bits->ftype].sub;


                    if (bits->ftype != TWINVQ_FT_SHORT && !tctx->is_6kbps)

            
                        get_bits(&gb, 2);


                    read_cb_data(tctx, &gb, bits->main_coeffs, bits->ftype);


                    for (i = 0; i < channels; i++)

            
                        for (j = 0; j < sub; j++)

            
                            for (k = 0; k < mtab->fmode[bits->ftype].bark_n_coef; k++)

            
                                bits->bark1[i][j][k] =

            
                                    get_bits(&gb, mtab->fmode[bits->ftype].bark_n_bit);


                    for (i = 0; i < channels; i++)

            
                        for (j = 0; j < sub; j++)

            
                            bits->bark_use_hist[i][j] = get_bits1(&gb);


                    if (bits->ftype == TWINVQ_FT_LONG) {

            
                        for (i = 0; i < channels; i++)

            
                            bits->gain_bits[i] = get_bits(&gb, TWINVQ_GAIN_BITS);

            
                    } else {

            
                        for (i = 0; i < channels; i++) {

            
                            bits->gain_bits[i] = get_bits(&gb, TWINVQ_GAIN_BITS);

            
                            for (j = 0; j < sub; j++)

            
                                bits->sub_gain_bits[i * sub + j] =

            
                                    get_bits(&gb, TWINVQ_SUB_GAIN_BITS);

            
                        }

            
                    }


                    for (i = 0; i < channels; i++) {

            
                        bits->lpc_hist_idx[i] = get_bits(&gb, mtab->lsp_bit0);

            
                        bits->lpc_idx1[i]     = get_bits(&gb, mtab->lsp_bit1);


                        for (j = 0; j < mtab->lsp_split; j++)

            
                            bits->lpc_idx2[i][j] = get_bits(&gb, mtab->lsp_bit2);

            
                    }


                    if (bits->ftype == TWINVQ_FT_LONG) {

            
                        read_cb_data(tctx, &gb, bits->ppc_coeffs, 3);

            
                        for (i = 0; i < channels; i++) {

            
                            bits->p_coef[i] = get_bits(&gb, mtab->ppc_period_bit);

            
                            bits->g_coef[i] = get_bits(&gb, mtab->pgain_bit);

            
                        }

            
                    }


                    // subframes are aligned to nibbles

            
                    if (get_bits_count(&gb) & 3)

            
                        skip_bits(&gb, 4 - (get_bits_count(&gb) & 3));

            
                }


                return (get_bits_count(&gb) + 7) / 8;

            
            }


            typedef struct MetasoundProps {

            
                uint32_t tag;

            
                int      bit_rate;

            
                int      channels;

            
                int      sample_rate;

            
            } MetasoundProps;


            static const MetasoundProps codec_props[] = {

            
                { MKTAG('V','X','0','3'),  6, 1,  8000 },

            
                { MKTAG('V','X','0','4'), 12, 2,  8000 },


                { MKTAG('V','O','X','i'),  8, 1,  8000 },

            
                { MKTAG('V','O','X','j'), 10, 1, 11025 },

            
                { MKTAG('V','O','X','k'), 16, 1, 16000 },

            
                { MKTAG('V','O','X','L'), 24, 1, 22050 },

            
                { MKTAG('V','O','X','q'), 32, 1, 44100 },

            
                { MKTAG('V','O','X','r'), 40, 1, 44100 },

            
                { MKTAG('V','O','X','s'), 48, 1, 44100 },

            
                { MKTAG('V','O','X','t'), 16, 2,  8000 },

            
                { MKTAG('V','O','X','u'), 20, 2, 11025 },

            
                { MKTAG('V','O','X','v'), 32, 2, 16000 },

            
                { MKTAG('V','O','X','w'), 48, 2, 22050 },

            
                { MKTAG('V','O','X','x'), 64, 2, 44100 },

            
                { MKTAG('V','O','X','y'), 80, 2, 44100 },

            
                { MKTAG('V','O','X','z'), 96, 2, 44100 },


                { 0, 0, 0, 0 }

            
            };


            static av_cold int metasound_decode_init(AVCodecContext *avctx)

            
            {

            
                int isampf, ibps;

            
                TwinVQContext *tctx = avctx->priv_data;

            
                uint32_t tag;

            
                const MetasoundProps *props = codec_props;

            
                int channels;


                if (!avctx->extradata || avctx->extradata_size < 16) {

            
                    av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata\n");

            
                    return AVERROR_INVALIDDATA;

            
                }


                tag = AV_RL32(avctx->extradata + 12);


                for (;;) {

            
                    if (!props->tag) {

            
                        av_log(avctx, AV_LOG_ERROR, "Could not find tag %08"PRIX32"\n", tag);

            
                        return AVERROR_INVALIDDATA;

            
                    }

            
                    if (props->tag == tag) {

            
                        avctx->sample_rate = props->sample_rate;

            
                        channels           = props->channels;

            
                        avctx->bit_rate    = props->bit_rate * 1000;

            
                        isampf             = avctx->sample_rate / 1000;

            
                        break;

            
                    }

            
                    props++;

            
                }


                av_channel_layout_uninit(&avctx->ch_layout);

            
                av_channel_layout_default(&avctx->ch_layout, channels);


                ibps = avctx->bit_rate / (1000 * channels);


                switch ((channels << 16) + (isampf << 8) + ibps) {

            
                case (1 << 16) + ( 8 << 8) +  6:

            
                    tctx->mtab = &metasound_mode0806;

            
                    break;

            
                case (2 << 16) + ( 8 << 8) +  6:

            
                    tctx->mtab = &metasound_mode0806s;

            
                    break;

            
                case (1 << 16) + ( 8 << 8) +  8:

            
                    tctx->mtab = &metasound_mode0808;

            
                    break;

            
                case (2 << 16) + ( 8 << 8) +  8:

            
                    tctx->mtab = &metasound_mode0808s;

            
                    break;

            
                case (1 << 16) + (11 << 8) + 10:

            
                    tctx->mtab = &metasound_mode1110;

            
                    break;

            
                case (2 << 16) + (11 << 8) + 10:

            
                    tctx->mtab = &metasound_mode1110s;

            
                    break;

            
                case (1 << 16) + (16 << 8) + 16:

            
                    tctx->mtab = &metasound_mode1616;

            
                    break;

            
                case (2 << 16) + (16 << 8) + 16:

            
                    tctx->mtab = &metasound_mode1616s;

            
                    break;

            
                case (1 << 16) + (22 << 8) + 24:

            
                    tctx->mtab = &metasound_mode2224;

            
                    break;

            
                case (2 << 16) + (22 << 8) + 24:

            
                    tctx->mtab = &metasound_mode2224s;

            
                    break;

            
                case (1 << 16) + (44 << 8) + 32:

            
                case (2 << 16) + (44 << 8) + 32:

            
                    tctx->mtab = &metasound_mode4432;

            
                    break;

            
                case (1 << 16) + (44 << 8) + 40:

            
                case (2 << 16) + (44 << 8) + 40:

            
                    tctx->mtab = &metasound_mode4440;

            
                    break;

            
                case (1 << 16) + (44 << 8) + 48:

            
                case (2 << 16) + (44 << 8) + 48:

            
                    tctx->mtab = &metasound_mode4448;

            
                    break;

            
                default:

            
                    av_log(avctx, AV_LOG_ERROR,

            
                           "This version does not support %d kHz - %d kbit/s/ch mode.\n",

            
                           isampf, ibps);

            
                    return AVERROR(ENOSYS);

            
                }


                tctx->codec          = TWINVQ_CODEC_METASOUND;

            
                tctx->read_bitstream = metasound_read_bitstream;

            
                tctx->dec_bark_env   = dec_bark_env;

            
                tctx->decode_ppc     = decode_ppc;

            
                tctx->frame_size     = avctx->bit_rate * tctx->mtab->size

            
                                                       / avctx->sample_rate;

            
                tctx->is_6kbps       = ibps == 6;


                return ff_twinvq_decode_init(avctx);

            
            }


            const FFCodec ff_metasound_decoder = {

            
                .p.name         = "metasound",

            
                CODEC_LONG_NAME("Voxware MetaSound"),

            
                .p.type         = AVMEDIA_TYPE_AUDIO,

            
                .p.id           = AV_CODEC_ID_METASOUND,

            
                .priv_data_size = sizeof(TwinVQContext),

            
                .init           = metasound_decode_init,

            
                .close          = ff_twinvq_decode_close,

            
                FF_CODEC_DECODE_CB(ff_twinvq_decode_frame),

            
                .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,

            
                .p.sample_fmts  = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,

            
                                                                  AV_SAMPLE_FMT_NONE },

            
                .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

            
            };
	/*
	* Voxware MetaSound decoder
	* Copyright (c) 2013 Konstantin Shishkov
	* based on 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 <inttypes.h>
	#include <math.h>
	#include <stdint.h>

	#include "libavutil/channel_layout.h"

	#define BITSTREAM_READER_LE
	#include "avcodec.h"
	#include "codec_internal.h"
	#include "get_bits.h"

	#include "twinvq.h"
	#include "metasound_data.h"

	static void add_peak(float period, int width, const float *shape,
	float ppc_gain, float *speech, int len)
	{
	int i, j, center;
	const float *shape_end = shape + len;

	// 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 = (int)(i * period + 0.5);
	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 = (int)(i * period + 0.5);
	for (j = -width / 2; j < (width + 1) / 2 && shape < shape_end; j++)
	speech[j + center] += ppc_gain * *shape++;
	}

	static void decode_ppc(TwinVQContext *tctx, int period_coef, int g_coef,
	const float shape, float speech)
	{
	const TwinVQModeTab *mtab = tctx->mtab;
	int channels = tctx->avctx->ch_layout.nb_channels;
	int isampf = tctx->avctx->sample_rate / 1000;
	int ibps = tctx->avctx->bit_rate / (1000 * channels);
	int width;

	float ratio = (float)mtab->size / isampf;
	float min_period, max_period, period_range, period;
	float some_mult;

	float pgain_base, pgain_step, ppc_gain;

	if (channels == 1) {
	min_period = log2(ratio * 0.2);
	max_period = min_period + log2(6);
	} else {
	min_period = (int)(ratio * 0.2 * 400 + 0.5) / 400.0;
	max_period = (int)(ratio * 0.2 * 400 * 6 + 0.5) / 400.0;
	}
	period_range = max_period - min_period;
	period = min_period + period_coef * period_range /
	((1 << mtab->ppc_period_bit) - 1);
	if (channels == 1)
	period = powf(2.0, period);
	else
	period = (int)(period * 400 + 0.5) / 400.0;

	switch (isampf) {
	case 8: some_mult = 2.0; break;
	case 11: some_mult = 3.0; break;
	case 16: some_mult = 3.0; break;
	case 22: some_mult = ibps == 32 ? 2.0 : 4.0; break;
	case 44: some_mult = 8.0; break;
	default: some_mult = 4.0;
	}

	width = (int)(some_mult / (mtab->size / period) * mtab->ppc_shape_len);
	if (isampf == 22 && ibps == 32)
	width = (int)((2.0 / period + 1) * width + 0.5);

	pgain_base = channels == 2 ? 25000.0 : 20000.0;
	pgain_step = pgain_base / ((1 << mtab->pgain_bit) - 1);
	ppc_gain = 1.0 / 8192 *
	twinvq_mulawinv(pgain_step * g_coef + pgain_step / 2,
	pgain_base, TWINVQ_PGAIN_MU);

	add_peak(period, width, shape, ppc_gain, speech, mtab->ppc_shape_len);
	}

	static void dec_bark_env(TwinVQContext tctx, const uint8_t in, int use_hist,
	int ch, float *out, float gain,
	enum TwinVQFrameType ftype)
	{
	const TwinVQModeTab *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;
	int channels = tctx->avctx->ch_layout.nb_channels;

	if (channels == 1)
	val = 0.5;
	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] *
	(1.0 / 2048);
	float st;

	if (channels == 1)
	st = use_hist ?
	tmp2 + val * hist[idx] + 1.0 : tmp2 + 1.0;
	else
	st = use_hist ? (1.0 - val) * tmp2 + val * hist[idx] + 1.0
	: tmp2 + 1.0;

	hist[idx] = tmp2;
	if (st < 0.1)
	st = 0.1;

	twinvq_memset_float(out, st * gain,
	mtab->fmode[ftype].bark_tab[idx]);
	out += mtab->fmode[ftype].bark_tab[idx];
	}
	}

	static void read_cb_data(TwinVQContext tctx, GetBitContext gb,
	uint8_t *dst, enum TwinVQFrameType ftype)
	{
	int i;

	for (i = 0; i < tctx->n_div[ftype]; i++) {
	int bs_second_part = (i >= tctx->bits_main_spec_change[ftype]);

	*dst++ = get_bits(gb, tctx->bits_main_spec[0][ftype][bs_second_part]);
	*dst++ = get_bits(gb, tctx->bits_main_spec[1][ftype][bs_second_part]);
	}
	}

	static int metasound_read_bitstream(AVCodecContext avctx, TwinVQContext tctx,
	const uint8_t *buf, int buf_size)
	{
	TwinVQFrameData *bits;
	const TwinVQModeTab *mtab = tctx->mtab;
	int channels = tctx->avctx->ch_layout.nb_channels;
	int sub;
	GetBitContext gb;
	int i, j, k, ret;

	if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
	return ret;

	for (tctx->cur_frame = 0; tctx->cur_frame < tctx->frames_per_packet;
	tctx->cur_frame++) {
	bits = tctx->bits + tctx->cur_frame;

	bits->window_type = get_bits(&gb, TWINVQ_WINDOW_TYPE_BITS);

	if (bits->window_type > 8) {
	av_log(avctx, AV_LOG_ERROR, "Invalid window type, broken sample?\n");
	return AVERROR_INVALIDDATA;
	}

	bits->ftype = ff_twinvq_wtype_to_ftype_table[tctx->bits[tctx->cur_frame].window_type];

	sub = mtab->fmode[bits->ftype].sub;

	if (bits->ftype != TWINVQ_FT_SHORT && !tctx->is_6kbps)
	get_bits(&gb, 2);

	read_cb_data(tctx, &gb, bits->main_coeffs, bits->ftype);

	for (i = 0; i < channels; i++)
	for (j = 0; j < sub; j++)
	for (k = 0; k < mtab->fmode[bits->ftype].bark_n_coef; k++)
	bits->bark1[i][j][k] =
	get_bits(&gb, mtab->fmode[bits->ftype].bark_n_bit);

	for (i = 0; i < channels; i++)
	for (j = 0; j < sub; j++)
	bits->bark_use_hist[i][j] = get_bits1(&gb);

	if (bits->ftype == TWINVQ_FT_LONG) {
	for (i = 0; i < channels; i++)
	bits->gain_bits[i] = get_bits(&gb, TWINVQ_GAIN_BITS);
	} else {
	for (i = 0; i < channels; i++) {
	bits->gain_bits[i] = get_bits(&gb, TWINVQ_GAIN_BITS);
	for (j = 0; j < sub; j++)
	bits->sub_gain_bits[i * sub + j] =
	get_bits(&gb, TWINVQ_SUB_GAIN_BITS);
	}
	}

	for (i = 0; i < channels; i++) {
	bits->lpc_hist_idx[i] = get_bits(&gb, mtab->lsp_bit0);
	bits->lpc_idx1[i] = get_bits(&gb, mtab->lsp_bit1);

	for (j = 0; j < mtab->lsp_split; j++)
	bits->lpc_idx2[i][j] = get_bits(&gb, mtab->lsp_bit2);
	}

	if (bits->ftype == TWINVQ_FT_LONG) {
	read_cb_data(tctx, &gb, bits->ppc_coeffs, 3);
	for (i = 0; i < channels; i++) {
	bits->p_coef[i] = get_bits(&gb, mtab->ppc_period_bit);
	bits->g_coef[i] = get_bits(&gb, mtab->pgain_bit);
	}
	}

	// subframes are aligned to nibbles
	if (get_bits_count(&gb) & 3)
	skip_bits(&gb, 4 - (get_bits_count(&gb) & 3));
	}

	return (get_bits_count(&gb) + 7) / 8;
	}

	typedef struct MetasoundProps {
	uint32_t tag;
	int bit_rate;
	int channels;
	int sample_rate;
	} MetasoundProps;

	static const MetasoundProps codec_props[] = {
	{ MKTAG('V','X','0','3'), 6, 1, 8000 },
	{ MKTAG('V','X','0','4'), 12, 2, 8000 },

	{ MKTAG('V','O','X','i'), 8, 1, 8000 },
	{ MKTAG('V','O','X','j'), 10, 1, 11025 },
	{ MKTAG('V','O','X','k'), 16, 1, 16000 },
	{ MKTAG('V','O','X','L'), 24, 1, 22050 },
	{ MKTAG('V','O','X','q'), 32, 1, 44100 },
	{ MKTAG('V','O','X','r'), 40, 1, 44100 },
	{ MKTAG('V','O','X','s'), 48, 1, 44100 },
	{ MKTAG('V','O','X','t'), 16, 2, 8000 },
	{ MKTAG('V','O','X','u'), 20, 2, 11025 },
	{ MKTAG('V','O','X','v'), 32, 2, 16000 },
	{ MKTAG('V','O','X','w'), 48, 2, 22050 },
	{ MKTAG('V','O','X','x'), 64, 2, 44100 },
	{ MKTAG('V','O','X','y'), 80, 2, 44100 },
	{ MKTAG('V','O','X','z'), 96, 2, 44100 },

	{ 0, 0, 0, 0 }
	};

	static av_cold int metasound_decode_init(AVCodecContext *avctx)
	{
	int isampf, ibps;
	TwinVQContext *tctx = avctx->priv_data;
	uint32_t tag;
	const MetasoundProps *props = codec_props;
	int channels;

	if (!avctx->extradata \|\| avctx->extradata_size < 16) {
	av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata\n");
	return AVERROR_INVALIDDATA;
	}

	tag = AV_RL32(avctx->extradata + 12);

	for (;;) {
	if (!props->tag) {
	av_log(avctx, AV_LOG_ERROR, "Could not find tag %08"PRIX32"\n", tag);
	return AVERROR_INVALIDDATA;
	}
	if (props->tag == tag) {
	avctx->sample_rate = props->sample_rate;
	channels = props->channels;
	avctx->bit_rate = props->bit_rate * 1000;
	isampf = avctx->sample_rate / 1000;
	break;
	}
	props++;
	}

	av_channel_layout_uninit(&avctx->ch_layout);
	av_channel_layout_default(&avctx->ch_layout, channels);

	ibps = avctx->bit_rate / (1000 * channels);

	switch ((channels << 16) + (isampf << 8) + ibps) {
	case (1 << 16) + ( 8 << 8) + 6:
	tctx->mtab = &metasound_mode0806;
	break;
	case (2 << 16) + ( 8 << 8) + 6:
	tctx->mtab = &metasound_mode0806s;
	break;
	case (1 << 16) + ( 8 << 8) + 8:
	tctx->mtab = &metasound_mode0808;
	break;
	case (2 << 16) + ( 8 << 8) + 8:
	tctx->mtab = &metasound_mode0808s;
	break;
	case (1 << 16) + (11 << 8) + 10:
	tctx->mtab = &metasound_mode1110;
	break;
	case (2 << 16) + (11 << 8) + 10:
	tctx->mtab = &metasound_mode1110s;
	break;
	case (1 << 16) + (16 << 8) + 16:
	tctx->mtab = &metasound_mode1616;
	break;
	case (2 << 16) + (16 << 8) + 16:
	tctx->mtab = &metasound_mode1616s;
	break;
	case (1 << 16) + (22 << 8) + 24:
	tctx->mtab = &metasound_mode2224;
	break;
	case (2 << 16) + (22 << 8) + 24:
	tctx->mtab = &metasound_mode2224s;
	break;
	case (1 << 16) + (44 << 8) + 32:
	case (2 << 16) + (44 << 8) + 32:
	tctx->mtab = &metasound_mode4432;
	break;
	case (1 << 16) + (44 << 8) + 40:
	case (2 << 16) + (44 << 8) + 40:
	tctx->mtab = &metasound_mode4440;
	break;
	case (1 << 16) + (44 << 8) + 48:
	case (2 << 16) + (44 << 8) + 48:
	tctx->mtab = &metasound_mode4448;
	break;
	default:
	av_log(avctx, AV_LOG_ERROR,
	"This version does not support %d kHz - %d kbit/s/ch mode.\n",
	isampf, ibps);
	return AVERROR(ENOSYS);
	}

	tctx->codec = TWINVQ_CODEC_METASOUND;
	tctx->read_bitstream = metasound_read_bitstream;
	tctx->dec_bark_env = dec_bark_env;
	tctx->decode_ppc = decode_ppc;
	tctx->frame_size = avctx->bit_rate * tctx->mtab->size
	/ avctx->sample_rate;
	tctx->is_6kbps = ibps == 6;

	return ff_twinvq_decode_init(avctx);
	}

	const FFCodec ff_metasound_decoder = {
	.p.name = "metasound",
	CODEC_LONG_NAME("Voxware MetaSound"),
	.p.type = AVMEDIA_TYPE_AUDIO,
	.p.id = AV_CODEC_ID_METASOUND,
	.priv_data_size = sizeof(TwinVQContext),
	.init = metasound_decode_init,
	.close = ff_twinvq_decode_close,
	FF_CODEC_DECODE_CB(ff_twinvq_decode_frame),
	.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_CHANNEL_CONF,
	.p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
	AV_SAMPLE_FMT_NONE },
	.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
	};