libavcodec/metasound.c - manifest_repos/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"
 #include "libavutil/float_dsp.h"

 #define BITSTREAM_READER_LE
 #include "avcodec.h"
 #include "fft.h"
 #include "get_bits.h"
 #include "internal.h"
 #include "lsp.h"
 #include "sinewin.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 isampf       = tctx->avctx->sample_rate / 1000;
     int ibps         = tctx->avctx->bit_rate / (1000 * tctx->avctx->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 (tctx->avctx->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 (tctx->avctx->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 = tctx->avctx->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;

     if (tctx->avctx->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 (tctx->avctx->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->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;

     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;
             avctx->channels    = props->channels;
             avctx->bit_rate    = props->bit_rate * 1000;
             isampf             = avctx->sample_rate / 1000;
             break;
         }
         props++;
     }

     if (avctx->channels <= 0 || avctx->channels > TWINVQ_CHANNELS_MAX) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %i\n",
                avctx->channels);
         return AVERROR_INVALIDDATA;
     }
     avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
                                                  : AV_CH_LAYOUT_STEREO;

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

     switch ((avctx->channels << 16) + (isampf << 8) + ibps) {
     case (1 << 16) + ( 8 << 8) +  6:
         tctx->mtab = &ff_metasound_mode0806;
         break;
     case (2 << 16) + ( 8 << 8) +  6:
         tctx->mtab = &ff_metasound_mode0806s;
         break;
     case (1 << 16) + ( 8 << 8) +  8:
         tctx->mtab = &ff_metasound_mode0808;
         break;
     case (2 << 16) + ( 8 << 8) +  8:
         tctx->mtab = &ff_metasound_mode0808s;
         break;
     case (1 << 16) + (11 << 8) + 10:
         tctx->mtab = &ff_metasound_mode1110;
         break;
     case (2 << 16) + (11 << 8) + 10:
         tctx->mtab = &ff_metasound_mode1110s;
         break;
     case (1 << 16) + (16 << 8) + 16:
         tctx->mtab = &ff_metasound_mode1616;
         break;
     case (2 << 16) + (16 << 8) + 16:
         tctx->mtab = &ff_metasound_mode1616s;
         break;
     case (1 << 16) + (22 << 8) + 24:
         tctx->mtab = &ff_metasound_mode2224;
         break;
     case (2 << 16) + (22 << 8) + 24:
         tctx->mtab = &ff_metasound_mode2224s;
         break;
     case (1 << 16) + (44 << 8) + 32:
         tctx->mtab = &ff_metasound_mode4432;
         break;
     case (2 << 16) + (44 << 8) + 32:
         tctx->mtab = &ff_metasound_mode4432s;
         break;
     case (1 << 16) + (44 << 8) + 40:
         tctx->mtab = &ff_metasound_mode4440;
         break;
     case (2 << 16) + (44 << 8) + 40:
         tctx->mtab = &ff_metasound_mode4440s;
         break;
     case (1 << 16) + (44 << 8) + 48:
         tctx->mtab = &ff_metasound_mode4448;
         break;
     case (2 << 16) + (44 << 8) + 48:
         tctx->mtab = &ff_metasound_mode4448s;
         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);
 }

 AVCodec ff_metasound_decoder = {
     .name           = "metasound",
     .long_name      = NULL_IF_CONFIG_SMALL("Voxware MetaSound"),
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = AV_CODEC_ID_METASOUND,
     .priv_data_size = sizeof(TwinVQContext),
     .init           = metasound_decode_init,
     .close          = ff_twinvq_decode_close,
     .decode         = ff_twinvq_decode_frame,
     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                       AV_SAMPLE_FMT_NONE },
 };
	/*
	* 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"
	#include "libavutil/float_dsp.h"

	#define BITSTREAM_READER_LE
	#include "avcodec.h"
	#include "fft.h"
	#include "get_bits.h"
	#include "internal.h"
	#include "lsp.h"
	#include "sinewin.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 isampf = tctx->avctx->sample_rate / 1000;
	int ibps = tctx->avctx->bit_rate / (1000 * tctx->avctx->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 (tctx->avctx->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 (tctx->avctx->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 = tctx->avctx->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;

	if (tctx->avctx->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 (tctx->avctx->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->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;

	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;
	avctx->channels = props->channels;
	avctx->bit_rate = props->bit_rate * 1000;
	isampf = avctx->sample_rate / 1000;
	break;
	}
	props++;
	}

	if (avctx->channels <= 0 \|\| avctx->channels > TWINVQ_CHANNELS_MAX) {
	av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %i\n",
	avctx->channels);
	return AVERROR_INVALIDDATA;
	}
	avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
	: AV_CH_LAYOUT_STEREO;

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

	switch ((avctx->channels << 16) + (isampf << 8) + ibps) {
	case (1 << 16) + ( 8 << 8) + 6:
	tctx->mtab = &ff_metasound_mode0806;
	break;
	case (2 << 16) + ( 8 << 8) + 6:
	tctx->mtab = &ff_metasound_mode0806s;
	break;
	case (1 << 16) + ( 8 << 8) + 8:
	tctx->mtab = &ff_metasound_mode0808;
	break;
	case (2 << 16) + ( 8 << 8) + 8:
	tctx->mtab = &ff_metasound_mode0808s;
	break;
	case (1 << 16) + (11 << 8) + 10:
	tctx->mtab = &ff_metasound_mode1110;
	break;
	case (2 << 16) + (11 << 8) + 10:
	tctx->mtab = &ff_metasound_mode1110s;
	break;
	case (1 << 16) + (16 << 8) + 16:
	tctx->mtab = &ff_metasound_mode1616;
	break;
	case (2 << 16) + (16 << 8) + 16:
	tctx->mtab = &ff_metasound_mode1616s;
	break;
	case (1 << 16) + (22 << 8) + 24:
	tctx->mtab = &ff_metasound_mode2224;
	break;
	case (2 << 16) + (22 << 8) + 24:
	tctx->mtab = &ff_metasound_mode2224s;
	break;
	case (1 << 16) + (44 << 8) + 32:
	tctx->mtab = &ff_metasound_mode4432;
	break;
	case (2 << 16) + (44 << 8) + 32:
	tctx->mtab = &ff_metasound_mode4432s;
	break;
	case (1 << 16) + (44 << 8) + 40:
	tctx->mtab = &ff_metasound_mode4440;
	break;
	case (2 << 16) + (44 << 8) + 40:
	tctx->mtab = &ff_metasound_mode4440s;
	break;
	case (1 << 16) + (44 << 8) + 48:
	tctx->mtab = &ff_metasound_mode4448;
	break;
	case (2 << 16) + (44 << 8) + 48:
	tctx->mtab = &ff_metasound_mode4448s;
	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);
	}

	AVCodec ff_metasound_decoder = {
	.name = "metasound",
	.long_name = NULL_IF_CONFIG_SMALL("Voxware MetaSound"),
	.type = AVMEDIA_TYPE_AUDIO,
	.id = AV_CODEC_ID_METASOUND,
	.priv_data_size = sizeof(TwinVQContext),
	.init = metasound_decode_init,
	.close = ff_twinvq_decode_close,
	.decode = ff_twinvq_decode_frame,
	.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_CHANNEL_CONF,
	.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
	AV_SAMPLE_FMT_NONE },
	};