/src/ffmpeg/libavcodec/g726.c

Source
/*
 * G.726 ADPCM audio codec
 * Copyright (c) 2004 Roman Shaposhnik
 *
 * This is a very straightforward rendition of the G.726
 * Section 4 "Computational Details".
 *
 * 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 "config_components.h"

#include <limits.h>

#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "codec_internal.h"
#include "decode.h"
#include "encode.h"
#include "get_bits.h"
#include "put_bits.h"

/**
 * G.726 11-bit float.
 * G.726 Standard uses rather odd 11-bit floating point arithmetic for
 * numerous occasions. It's a mystery to me why they did it this way
 * instead of simply using 32-bit integer arithmetic.
 */
typedef struct Float11 {
    uint8_t sign;   /**< 1 bit sign */
    uint8_t exp;    /**< 4 bits exponent */
    uint8_t mant;   /**< 6 bits mantissa */
} Float11;

static inline Float11* i2f(int i, Float11* f)
{
    f->sign = (i < 0);
    if (f->sign)
        i = -i;
    f->exp = av_log2_16bit(i) + !!i;
    f->mant = i? (i<<6) >> f->exp : 1<<5;
    return f;
}

static inline int16_t mult(Float11* f1, Float11* f2)
{
        int res, exp;

        exp = f1->exp + f2->exp;
        res = (((f1->mant * f2->mant) + 0x30) >> 4);
        res = exp > 19 ? res << (exp - 19) : res >> (19 - exp);
        return (f1->sign ^ f2->sign) ? -res : res;
}

static inline int sgn(int value)
{
    return (value < 0) ? -1 : 1;
}

typedef struct G726Tables {
    const int* quant;         /**< quantization table */
    const int16_t* iquant;    /**< inverse quantization table */
    const int16_t* W;         /**< special table #1 ;-) */
    const uint8_t* F;         /**< special table #2 */
} G726Tables;

typedef struct G726Context {
    AVClass *class;
    G726Tables tbls;    /**< static tables needed for computation */

    Float11 sr[2];      /**< prev. reconstructed samples */
    Float11 dq[6];      /**< prev. difference */
    int a[2];           /**< second order predictor coeffs */
    int b[6];           /**< sixth order predictor coeffs */
    int pk[2];          /**< signs of prev. 2 sez + dq */

    int ap;             /**< scale factor control */
    int yu;             /**< fast scale factor */
    int yl;             /**< slow scale factor */
    int dms;            /**< short average magnitude of F[i] */
    int dml;            /**< long average magnitude of F[i] */
    int td;             /**< tone detect */

    int se;             /**< estimated signal for the next iteration */
    int sez;            /**< estimated second order prediction */
    int y;              /**< quantizer scaling factor for the next iteration */
    int code_size;
    int little_endian;  /**< little-endian bitstream as used in aiff and Sun AU */
} G726Context;

static const int quant_tbl16[] =                  /**< 16kbit/s 2 bits per sample */
           { 260, INT_MAX };
static const int16_t iquant_tbl16[] =
           { 116, 365, 365, 116 };
static const int16_t W_tbl16[] =
           { -22, 439, 439, -22 };
static const uint8_t F_tbl16[] =
           { 0, 7, 7, 0 };

static const int quant_tbl24[] =                  /**< 24kbit/s 3 bits per sample */
           {  7, 217, 330, INT_MAX };
static const int16_t iquant_tbl24[] =
           { INT16_MIN, 135, 273, 373, 373, 273, 135, INT16_MIN };
static const int16_t W_tbl24[] =
           { -4,  30, 137, 582, 582, 137,  30, -4 };
static const uint8_t F_tbl24[] =
           { 0, 1, 2, 7, 7, 2, 1, 0 };

static const int quant_tbl32[] =                  /**< 32kbit/s 4 bits per sample */
           { -125,  79, 177, 245, 299, 348, 399, INT_MAX };
static const int16_t iquant_tbl32[] =
         { INT16_MIN,   4, 135, 213, 273, 323, 373, 425,
                 425, 373, 323, 273, 213, 135,   4, INT16_MIN };
static const int16_t W_tbl32[] =
           { -12,  18,  41,  64, 112, 198, 355, 1122,
            1122, 355, 198, 112,  64,  41,  18, -12};
static const uint8_t F_tbl32[] =
           { 0, 0, 0, 1, 1, 1, 3, 7, 7, 3, 1, 1, 1, 0, 0, 0 };

static const int quant_tbl40[] =                  /**< 40kbit/s 5 bits per sample */
           { -122, -16,  67, 138, 197, 249, 297, 338,
              377, 412, 444, 474, 501, 527, 552, INT_MAX };
static const int16_t iquant_tbl40[] =
         { INT16_MIN, -66,  28, 104, 169, 224, 274, 318,
                 358, 395, 429, 459, 488, 514, 539, 566,
                 566, 539, 514, 488, 459, 429, 395, 358,
                 318, 274, 224, 169, 104,  28, -66, INT16_MIN };
static const int16_t W_tbl40[] =
           {   14,  14,  24,  39,  40,  41,   58,  100,
              141, 179, 219, 280, 358, 440,  529,  696,
              696, 529, 440, 358, 280, 219,  179,  141,
              100,  58,  41,  40,  39,  24,   14,   14 };
static const uint8_t F_tbl40[] =
           { 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 6,
             6, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };

static const G726Tables G726Tables_pool[] =
           {{ quant_tbl16, iquant_tbl16, W_tbl16, F_tbl16 },
            { quant_tbl24, iquant_tbl24, W_tbl24, F_tbl24 },
            { quant_tbl32, iquant_tbl32, W_tbl32, F_tbl32 },
            { quant_tbl40, iquant_tbl40, W_tbl40, F_tbl40 }};


/**
 * Paragraph 4.2.2 page 18: Adaptive quantizer.
 */
static inline uint8_t quant(G726Context* c, int d)
{
    int sign, exp, i, dln;

    sign = i = 0;
    if (d < 0) {
        sign = 1;
        d = -d;
    }
    exp = av_log2_16bit(d);
    dln = ((exp<<7) + (((d<<7)>>exp)&0x7f)) - (c->y>>2);

    while (c->tbls.quant[i] < INT_MAX && c->tbls.quant[i] < dln)
        ++i;

    if (sign)
        i = ~i;
    if (c->code_size != 2 && i == 0) /* I'm not sure this is a good idea */
        i = 0xff;

    return i;
}

/**
 * Paragraph 4.2.3 page 22: Inverse adaptive quantizer.
 */
static inline int16_t inverse_quant(G726Context* c, int i)
{
    int dql, dex, dqt;

    dql = c->tbls.iquant[i] + (c->y >> 2);
    dex = (dql>>7) & 0xf;        /* 4-bit exponent */
    dqt = (1<<7) + (dql & 0x7f); /* log2 -> linear */
    return (dql < 0) ? 0 : ((dqt<<dex) >> 7);
}

static int16_t g726_decode(G726Context* c, int I)
{
    int dq, re_signal, pk0, fa1, i, tr, ylint, ylfrac, thr2, al, dq0;
    Float11 f;
    int I_sig= I >> (c->code_size - 1);

    dq = inverse_quant(c, I);

    /* Transition detect */
    ylint = (c->yl >> 15);
    ylfrac = (c->yl >> 10) & 0x1f;
    thr2 = (ylint > 9) ? 0x1f << 10 : (0x20 + ylfrac) << ylint;
    tr= (c->td == 1 && dq > ((3*thr2)>>2));

    if (I_sig)  /* get the sign */
        dq = -dq;
    re_signal = (int16_t)(c->se + dq);

    /* Update second order predictor coefficient A2 and A1 */
    pk0 = (c->sez + dq) ? sgn(c->sez + dq) : 0;
    dq0 = dq ? sgn(dq) : 0;
    if (tr) {
        c->a[0] = 0;
        c->a[1] = 0;
        for (i=0; i<6; i++)
            c->b[i] = 0;
    } else {
        /* This is a bit crazy, but it really is +255 not +256 */
        fa1 = av_clip_intp2((-c->a[0]*c->pk[0]*pk0)>>5, 8);

        c->a[1] += 128*pk0*c->pk[1] + fa1 - (c->a[1]>>7);
        c->a[1] = av_clip(c->a[1], -12288, 12288);
        c->a[0] += 64*3*pk0*c->pk[0] - (c->a[0] >> 8);
        c->a[0] = av_clip(c->a[0], -(15360 - c->a[1]), 15360 - c->a[1]);

        for (i=0; i<6; i++)
            c->b[i] += 128*dq0*sgn(-c->dq[i].sign) - (c->b[i]>>8);
    }

    /* Update Dq and Sr and Pk */
    c->pk[1] = c->pk[0];
    c->pk[0] = pk0 ? pk0 : 1;
    c->sr[1] = c->sr[0];
    i2f(re_signal, &c->sr[0]);
    for (i=5; i>0; i--)
        c->dq[i] = c->dq[i-1];
    i2f(dq, &c->dq[0]);
    c->dq[0].sign = I_sig; /* Isn't it crazy ?!?! */

    c->td = c->a[1] < -11776;

    /* Update Ap */
    c->dms += (c->tbls.F[I]<<4) + ((- c->dms) >> 5);
    c->dml += (c->tbls.F[I]<<4) + ((- c->dml) >> 7);
    if (tr)
        c->ap = 256;
    else {
        c->ap += (-c->ap) >> 4;
        if (c->y <= 1535 || c->td || abs((c->dms << 2) - c->dml) >= (c->dml >> 3))
            c->ap += 0x20;
    }

    /* Update Yu and Yl */
    c->yu = av_clip(c->y + c->tbls.W[I] + ((-c->y)>>5), 544, 5120);
    c->yl += c->yu + ((-c->yl)>>6);

    /* Next iteration for Y */
    al = (c->ap >= 256) ? 1<<6 : c->ap >> 2;
    c->y = (c->yl + (c->yu - (c->yl>>6))*al) >> 6;

    /* Next iteration for SE and SEZ */
    c->se = 0;
    for (i=0; i<6; i++)
        c->se += mult(i2f(c->b[i] >> 2, &f), &c->dq[i]);
    c->sez = c->se >> 1;
    for (i=0; i<2; i++)
        c->se += mult(i2f(c->a[i] >> 2, &f), &c->sr[i]);
    c->se >>= 1;

    return av_clip(re_signal * 4, -0xffff, 0xffff);
}

static av_cold int g726_reset(G726Context *c)
{
    int i;

    c->tbls = G726Tables_pool[c->code_size - 2];
    for (i=0; i<2; i++) {
        c->sr[i].mant = 1<<5;
        c->pk[i] = 1;
    }
    for (i=0; i<6; i++) {
        c->dq[i].mant = 1<<5;
    }
    c->yu = 544;
    c->yl = 34816;

    c->y = 544;

    return 0;
}

#if CONFIG_ADPCM_G726_ENCODER || CONFIG_ADPCM_G726LE_ENCODER
static int16_t g726_encode(G726Context* c, int16_t sig)
{
    uint8_t i;

    i = av_zero_extend(quant(c, sig/4 - c->se), c->code_size);
    g726_decode(c, i);
    return i;
}

/* Interfacing to the libavcodec */

static av_cold int g726_encode_init(AVCodecContext *avctx)
{
    G726Context* c = avctx->priv_data;

    c->little_endian = !strcmp(avctx->codec->name, "g726le");

    if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL &&
        avctx->sample_rate != 8000) {
        av_log(avctx, AV_LOG_ERROR, "Sample rates other than 8kHz are not "
               "allowed when the compliance level is higher than unofficial. "
               "Resample or reduce the compliance level.\n");
        return AVERROR(EINVAL);
    }
    if (avctx->sample_rate <= 0) {
        av_log(avctx, AV_LOG_ERROR, "Invalid sample rate %d\n",
               avctx->sample_rate);
        return AVERROR(EINVAL);
    }

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

    if (avctx->bit_rate)
        c->code_size = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate;

    c->code_size = av_clip(c->code_size, 2, 5);
    avctx->bit_rate = c->code_size * avctx->sample_rate;
    avctx->bits_per_coded_sample = c->code_size;

    g726_reset(c);

    /* select a frame size that will end on a byte boundary and have a size of
       approximately 1024 bytes */
    avctx->frame_size = ((int[]){ 4096, 2736, 2048, 1640 })[c->code_size - 2];

    return 0;
}

static int g726_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                             const AVFrame *frame, int *got_packet_ptr)
{
    G726Context *c = avctx->priv_data;
    const int16_t *samples = (const int16_t *)frame->data[0];
    PutBitContext pb;
    int i, ret, out_size;

    out_size = (frame->nb_samples * c->code_size + 7) / 8;
    if ((ret = ff_get_encode_buffer(avctx, avpkt, out_size, 0)) < 0)
        return ret;
    init_put_bits(&pb, avpkt->data, avpkt->size);

    for (i = 0; i < frame->nb_samples; i++)
        if (c->little_endian) {
            put_bits_le(&pb, c->code_size, g726_encode(c, *samples++));
        } else {
            put_bits(&pb, c->code_size, g726_encode(c, *samples++));
        }

    if (c->little_endian) {
        flush_put_bits_le(&pb);
    } else {
        flush_put_bits(&pb);
    }

    *got_packet_ptr = 1;
    return 0;
}

#define OFFSET(x) offsetof(G726Context, x)
#define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
    { "code_size", "Bits per code", OFFSET(code_size), AV_OPT_TYPE_INT, { .i64 = 4 }, 2, 5, AE },
    { NULL },
};

static const AVClass g726_class = {
    .class_name = "g726",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

static const FFCodecDefault defaults[] = {
    { "b", "0" },
    { NULL },
};
#endif

#if CONFIG_ADPCM_G726_ENCODER
const FFCodec ff_adpcm_g726_encoder = {
    .p.name         = "g726",
    CODEC_LONG_NAME("G.726 ADPCM"),
    .p.type         = AVMEDIA_TYPE_AUDIO,
    .p.id           = AV_CODEC_ID_ADPCM_G726,
    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SMALL_LAST_FRAME |
                      AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
    .priv_data_size = sizeof(G726Context),
    .init           = g726_encode_init,
    FF_CODEC_ENCODE_CB(g726_encode_frame),
    CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16),
    .p.priv_class   = &g726_class,
    .defaults       = defaults,
};
#endif

#if CONFIG_ADPCM_G726LE_ENCODER
const FFCodec ff_adpcm_g726le_encoder = {
    .p.name         = "g726le",
    CODEC_LONG_NAME("G.726 little endian ADPCM (\"right-justified\")"),
    .p.type         = AVMEDIA_TYPE_AUDIO,
    .p.id           = AV_CODEC_ID_ADPCM_G726LE,
    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SMALL_LAST_FRAME |
                      AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
    .priv_data_size = sizeof(G726Context),
    .init           = g726_encode_init,
    FF_CODEC_ENCODE_CB(g726_encode_frame),
    CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16),
    .p.priv_class   = &g726_class,
    .defaults       = defaults,
};
#endif

#if CONFIG_ADPCM_G726_DECODER || CONFIG_ADPCM_G726LE_DECODER
static av_cold int g726_decode_init(AVCodecContext *avctx)
{
    G726Context* c = avctx->priv_data;

    if (avctx->ch_layout.nb_channels > 1){
        avpriv_request_sample(avctx, "Decoding more than one channel");
        return AVERROR_PATCHWELCOME;
    }
    av_channel_layout_uninit(&avctx->ch_layout);
    avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

    c->little_endian = !strcmp(avctx->codec->name, "g726le");

    c->code_size = avctx->bits_per_coded_sample;
    if (c->code_size < 2 || c->code_size > 5) {
        av_log(avctx, AV_LOG_ERROR, "Invalid number of bits %d\n", c->code_size);
        return AVERROR(EINVAL);
    }
    g726_reset(c);

    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
    if (!avctx->sample_rate)
        avctx->sample_rate = 8000;

    return 0;
}

static int g726_decode_frame(AVCodecContext *avctx, AVFrame *frame,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    G726Context *c = avctx->priv_data;
    int16_t *samples;
    GetBitContext gb;
    int out_samples, ret;

    out_samples = buf_size * 8 / c->code_size;

    /* get output buffer */
    frame->nb_samples = out_samples;
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
        return ret;
    samples = (int16_t *)frame->data[0];

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

    while (out_samples--)
        *samples++ = g726_decode(c, c->little_endian ?
                                    get_bits_le(&gb, c->code_size) :
                                    get_bits(&gb, c->code_size));

    if (get_bits_left(&gb) > 0)
        av_log(avctx, AV_LOG_ERROR, "Frame invalidly split, missing parser?\n");

    *got_frame_ptr = 1;

    return buf_size;
}

static void g726_decode_flush(AVCodecContext *avctx)
{
    G726Context *c = avctx->priv_data;
    g726_reset(c);
}
#endif

#if CONFIG_ADPCM_G726_DECODER
const FFCodec ff_adpcm_g726_decoder = {
    .p.name         = "g726",
    CODEC_LONG_NAME("G.726 ADPCM"),
    .p.type         = AVMEDIA_TYPE_AUDIO,
    .p.id           = AV_CODEC_ID_ADPCM_G726,
    .priv_data_size = sizeof(G726Context),
    .init           = g726_decode_init,
    FF_CODEC_DECODE_CB(g726_decode_frame),
    .flush          = g726_decode_flush,
    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
};
#endif

#if CONFIG_ADPCM_G726LE_DECODER
const FFCodec ff_adpcm_g726le_decoder = {
    .p.name         = "g726le",
    .p.type         = AVMEDIA_TYPE_AUDIO,
    .p.id           = AV_CODEC_ID_ADPCM_G726LE,
    .priv_data_size = sizeof(G726Context),
    .init           = g726_decode_init,
    FF_CODEC_DECODE_CB(g726_decode_frame),
    .flush          = g726_decode_flush,
    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
    CODEC_LONG_NAME("G.726 ADPCM little-endian"),
};
#endif

Coverage Report

Created: 2026-01-16 07:48

Line	Count	Source
1		/*
2		* G.726 ADPCM audio codec
3		* Copyright (c) 2004 Roman Shaposhnik
4		*
5		* This is a very straightforward rendition of the G.726
6		* Section 4 "Computational Details".
7		*
8		* This file is part of FFmpeg.
9		*
10		* FFmpeg is free software; you can redistribute it and/or
11		* modify it under the terms of the GNU Lesser General Public
12		* License as published by the Free Software Foundation; either
13		* version 2.1 of the License, or (at your option) any later version.
14		*
15		* FFmpeg is distributed in the hope that it will be useful,
16		* but WITHOUT ANY WARRANTY; without even the implied warranty of
17		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18		* Lesser General Public License for more details.
19		*
20		* You should have received a copy of the GNU Lesser General Public
21		* License along with FFmpeg; if not, write to the Free Software
22		* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23		*/
24
25		#include "config_components.h"
26
27		#include <limits.h>
28
29		#include "libavutil/channel_layout.h"
30		#include "libavutil/opt.h"
31		#include "avcodec.h"
32		#include "codec_internal.h"
33		#include "decode.h"
34		#include "encode.h"
35		#include "get_bits.h"
36		#include "put_bits.h"
37
38		/**
39		* G.726 11-bit float.
40		* G.726 Standard uses rather odd 11-bit floating point arithmetic for
41		* numerous occasions. It's a mystery to me why they did it this way
42		* instead of simply using 32-bit integer arithmetic.
43		*/
44		typedef struct Float11 {
45		uint8_t sign; /*< 1 bit sign /
46		uint8_t exp; /*< 4 bits exponent /
47		uint8_t mant; /*< 6 bits mantissa /
48		} Float11;
49
50		static inline Float11* i2f(int i, Float11* f)
51	974M	{
52	974M	f->sign = (i < 0);
53	974M	if (f->sign)
54	275M	i = -i;
55	974M	f->exp = av_log2_16bit(i) + !!i;
56	974M	f->mant = i? (i<<6) >> f->exp : 1<<5;
57	974M	return f;
58	974M	}
59
60		static inline int16_t mult(Float11* f1, Float11* f2)
61	779M	{
62	779M	int res, exp;
63
64	779M	exp = f1->exp + f2->exp;
65	779M	res = (((f1->mant * f2->mant) + 0x30) >> 4);
66	779M	res = exp > 19 ? res << (exp - 19) : res >> (19 - exp);
67	779M	return (f1->sign ^ f2->sign) ? -res : res;
68	779M	}
69
70		static inline int sgn(int value)
71	752M	{
72	752M	return (value < 0) ? -1 : 1;
73	752M	}
74
75		typedef struct G726Tables {
76		const int* quant; /*< quantization table /
77		const int16_t* iquant; /*< inverse quantization table /
78		const int16_t* W; /*< special table #1 ;-) /
79		const uint8_t* F; /*< special table #2 /
80		} G726Tables;
81
82		typedef struct G726Context {
83		AVClass *class;
84		G726Tables tbls; /*< static tables needed for computation /
85
86		Float11 sr[2]; /*< prev. reconstructed samples /
87		Float11 dq[6]; /*< prev. difference /
88		int a[2]; /*< second order predictor coeffs /
89		int b[6]; /*< sixth order predictor coeffs /
90		int pk[2]; /*< signs of prev. 2 sez + dq /
91
92		int ap; /*< scale factor control /
93		int yu; /*< fast scale factor /
94		int yl; /*< slow scale factor /
95		int dms; /*< short average magnitude of F[i] /
96		int dml; /*< long average magnitude of F[i] /
97		int td; /*< tone detect /
98
99		int se; /*< estimated signal for the next iteration /
100		int sez; /*< estimated second order prediction /
101		int y; /*< quantizer scaling factor for the next iteration /
102		int code_size;
103		int little_endian; /*< little-endian bitstream as used in aiff and Sun AU /
104		} G726Context;
105
106		static const int quant_tbl16[] = /*< 16kbit/s 2 bits per sample /
107		{ 260, INT_MAX };
108		static const int16_t iquant_tbl16[] =
109		{ 116, 365, 365, 116 };
110		static const int16_t W_tbl16[] =
111		{ -22, 439, 439, -22 };
112		static const uint8_t F_tbl16[] =
113		{ 0, 7, 7, 0 };
114
115		static const int quant_tbl24[] = /*< 24kbit/s 3 bits per sample /
116		{ 7, 217, 330, INT_MAX };
117		static const int16_t iquant_tbl24[] =
118		{ INT16_MIN, 135, 273, 373, 373, 273, 135, INT16_MIN };
119		static const int16_t W_tbl24[] =
120		{ -4, 30, 137, 582, 582, 137, 30, -4 };
121		static const uint8_t F_tbl24[] =
122		{ 0, 1, 2, 7, 7, 2, 1, 0 };
123
124		static const int quant_tbl32[] = /*< 32kbit/s 4 bits per sample /
125		{ -125, 79, 177, 245, 299, 348, 399, INT_MAX };
126		static const int16_t iquant_tbl32[] =
127		{ INT16_MIN, 4, 135, 213, 273, 323, 373, 425,
128		425, 373, 323, 273, 213, 135, 4, INT16_MIN };
129		static const int16_t W_tbl32[] =
130		{ -12, 18, 41, 64, 112, 198, 355, 1122,
131		1122, 355, 198, 112, 64, 41, 18, -12};
132		static const uint8_t F_tbl32[] =
133		{ 0, 0, 0, 1, 1, 1, 3, 7, 7, 3, 1, 1, 1, 0, 0, 0 };
134
135		static const int quant_tbl40[] = /*< 40kbit/s 5 bits per sample /
136		{ -122, -16, 67, 138, 197, 249, 297, 338,
137		377, 412, 444, 474, 501, 527, 552, INT_MAX };
138		static const int16_t iquant_tbl40[] =
139		{ INT16_MIN, -66, 28, 104, 169, 224, 274, 318,
140		358, 395, 429, 459, 488, 514, 539, 566,
141		566, 539, 514, 488, 459, 429, 395, 358,
142		318, 274, 224, 169, 104, 28, -66, INT16_MIN };
143		static const int16_t W_tbl40[] =
144		{ 14, 14, 24, 39, 40, 41, 58, 100,
145		141, 179, 219, 280, 358, 440, 529, 696,
146		696, 529, 440, 358, 280, 219, 179, 141,
147		100, 58, 41, 40, 39, 24, 14, 14 };
148		static const uint8_t F_tbl40[] =
149		{ 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 6,
150		6, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
151
152		static const G726Tables G726Tables_pool[] =
153		{{ quant_tbl16, iquant_tbl16, W_tbl16, F_tbl16 },
154		{ quant_tbl24, iquant_tbl24, W_tbl24, F_tbl24 },
155		{ quant_tbl32, iquant_tbl32, W_tbl32, F_tbl32 },
156		{ quant_tbl40, iquant_tbl40, W_tbl40, F_tbl40 }};
157
158
159		/**
160		* Paragraph 4.2.2 page 18: Adaptive quantizer.
161		*/
162		static inline uint8_t quant(G726Context* c, int d)
163	0	{
164	0	int sign, exp, i, dln;
165
166	0	sign = i = 0;
167	0	if (d < 0) {
168	0	sign = 1;
169	0	d = -d;
170	0	}
171	0	exp = av_log2_16bit(d);
172	0	dln = ((exp<<7) + (((d<<7)>>exp)&0x7f)) - (c->y>>2);
173
174	0	while (c->tbls.quant[i] < INT_MAX && c->tbls.quant[i] < dln)
175	0	++i;
176
177	0	if (sign)
178	0	i = ~i;
179	0	if (c->code_size != 2 && i == 0) /* I'm not sure this is a good idea */
180	0	i = 0xff;
181
182	0	return i;
183	0	}
184
185		/**
186		* Paragraph 4.2.3 page 22: Inverse adaptive quantizer.
187		*/
188		static inline int16_t inverse_quant(G726Context* c, int i)
189	97.4M	{
190	97.4M	int dql, dex, dqt;
191
192	97.4M	dql = c->tbls.iquant[i] + (c->y >> 2);
193	97.4M	dex = (dql>>7) & 0xf; /* 4-bit exponent */
194	97.4M	dqt = (1<<7) + (dql & 0x7f); /* log2 -> linear */
195	97.4M	return (dql < 0) ? 0 : ((dqt<<dex) >> 7);
196	97.4M	}
197
198		static int16_t g726_decode(G726Context* c, int I)
199	97.4M	{
200	97.4M	int dq, re_signal, pk0, fa1, i, tr, ylint, ylfrac, thr2, al, dq0;
201	97.4M	Float11 f;
202	97.4M	int I_sig= I >> (c->code_size - 1);
203
204	97.4M	dq = inverse_quant(c, I);
205
206		/* Transition detect */
207	97.4M	ylint = (c->yl >> 15);
208	97.4M	ylfrac = (c->yl >> 10) & 0x1f;
209	97.4M	thr2 = (ylint > 9) ? 0x1f << 10 : (0x20 + ylfrac) << ylint;
210	97.4M	tr= (c->td == 1 && dq > ((3*thr2)>>2));
211
212	97.4M	if (I_sig) /* get the sign */
213	23.9M	dq = -dq;
214	97.4M	re_signal = (int16_t)(c->se + dq);
215
216		/* Update second order predictor coefficient A2 and A1 */
217	97.4M	pk0 = (c->sez + dq) ? sgn(c->sez + dq) : 0;
218	97.4M	dq0 = dq ? sgn(dq) : 0;
219	97.4M	if (tr) {
220	57.0k	c->a[0] = 0;
221	57.0k	c->a[1] = 0;
222	399k	for (i=0; i<6; i++)
223	342k	c->b[i] = 0;
224	97.4M	} else {
225		/* This is a bit crazy, but it really is +255 not +256 */
226	97.4M	fa1 = av_clip_intp2((-c->a[0]c->pk[0]pk0)>>5, 8);
227
228	97.4M	c->a[1] += 128pk0c->pk[1] + fa1 - (c->a[1]>>7);
229	97.4M	c->a[1] = av_clip(c->a[1], -12288, 12288);
230	97.4M	c->a[0] += 643pk0*c->pk[0] - (c->a[0] >> 8);
231	97.4M	c->a[0] = av_clip(c->a[0], -(15360 - c->a[1]), 15360 - c->a[1]);
232
233	681M	for (i=0; i<6; i++)
234	584M	c->b[i] += 128dq0sgn(-c->dq[i].sign) - (c->b[i]>>8);
235	97.4M	}
236
237		/* Update Dq and Sr and Pk */
238	97.4M	c->pk[1] = c->pk[0];
239	97.4M	c->pk[0] = pk0 ? pk0 : 1;
240	97.4M	c->sr[1] = c->sr[0];
241	97.4M	i2f(re_signal, &c->sr[0]);
242	584M	for (i=5; i>0; i--)
243	487M	c->dq[i] = c->dq[i-1];
244	97.4M	i2f(dq, &c->dq[0]);
245	97.4M	c->dq[0].sign = I_sig; /* Isn't it crazy ?!?! */
246
247	97.4M	c->td = c->a[1] < -11776;
248
249		/* Update Ap */
250	97.4M	c->dms += (c->tbls.F[I]<<4) + ((- c->dms) >> 5);
251	97.4M	c->dml += (c->tbls.F[I]<<4) + ((- c->dml) >> 7);
252	97.4M	if (tr)
253	57.0k	c->ap = 256;
254	97.4M	else {
255	97.4M	c->ap += (-c->ap) >> 4;
256	97.4M	if (c->y <= 1535 \|\| c->td \|\| abs((c->dms << 2) - c->dml) >= (c->dml >> 3))
257	76.5M	c->ap += 0x20;
258	97.4M	}
259
260		/* Update Yu and Yl */
261	97.4M	c->yu = av_clip(c->y + c->tbls.W[I] + ((-c->y)>>5), 544, 5120);
262	97.4M	c->yl += c->yu + ((-c->yl)>>6);
263
264		/* Next iteration for Y */
265	97.4M	al = (c->ap >= 256) ? 1<<6 : c->ap >> 2;
266	97.4M	c->y = (c->yl + (c->yu - (c->yl>>6))*al) >> 6;
267
268		/* Next iteration for SE and SEZ */
269	97.4M	c->se = 0;
270	682M	for (i=0; i<6; i++)
271	584M	c->se += mult(i2f(c->b[i] >> 2, &f), &c->dq[i]);
272	97.4M	c->sez = c->se >> 1;
273	292M	for (i=0; i<2; i++)
274	194M	c->se += mult(i2f(c->a[i] >> 2, &f), &c->sr[i]);
275	97.4M	c->se >>= 1;
276
277	97.4M	return av_clip(re_signal * 4, -0xffff, 0xffff);
278	97.4M	}
279
280		static av_cold int g726_reset(G726Context *c)
281	85.5k	{
282	85.5k	int i;
283
284	85.5k	c->tbls = G726Tables_pool[c->code_size - 2];
285	256k	for (i=0; i<2; i++) {
286	171k	c->sr[i].mant = 1<<5;
287	171k	c->pk[i] = 1;
288	171k	}
289	598k	for (i=0; i<6; i++) {
290	513k	c->dq[i].mant = 1<<5;
291	513k	}
292	85.5k	c->yu = 544;
293	85.5k	c->yl = 34816;
294
295	85.5k	c->y = 544;
296
297	85.5k	return 0;
298	85.5k	}
299
300		#if CONFIG_ADPCM_G726_ENCODER \|\| CONFIG_ADPCM_G726LE_ENCODER
301		static int16_t g726_encode(G726Context* c, int16_t sig)
302	0	{
303	0	uint8_t i;
304
305	0	i = av_zero_extend(quant(c, sig/4 - c->se), c->code_size);
306	0	g726_decode(c, i);
307	0	return i;
308	0	}
309
310		/* Interfacing to the libavcodec */
311
312		static av_cold int g726_encode_init(AVCodecContext *avctx)
313	0	{
314	0	G726Context* c = avctx->priv_data;
315
316	0	c->little_endian = !strcmp(avctx->codec->name, "g726le");
317
318	0	if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL &&
319	0	avctx->sample_rate != 8000) {
320	0	av_log(avctx, AV_LOG_ERROR, "Sample rates other than 8kHz are not "
321	0	"allowed when the compliance level is higher than unofficial. "
322	0	"Resample or reduce the compliance level.\n");
323	0	return AVERROR(EINVAL);
324	0	}
325	0	if (avctx->sample_rate <= 0) {
326	0	av_log(avctx, AV_LOG_ERROR, "Invalid sample rate %d\n",
327	0	avctx->sample_rate);
328	0	return AVERROR(EINVAL);
329	0	}
330
331	0	if (avctx->ch_layout.nb_channels != 1) {
332	0	av_log(avctx, AV_LOG_ERROR, "Only mono is supported\n");
333	0	return AVERROR(EINVAL);
334	0	}
335
336	0	if (avctx->bit_rate)
337	0	c->code_size = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate;
338
339	0	c->code_size = av_clip(c->code_size, 2, 5);
340	0	avctx->bit_rate = c->code_size * avctx->sample_rate;
341	0	avctx->bits_per_coded_sample = c->code_size;
342
343	0	g726_reset(c);
344
345		/* select a frame size that will end on a byte boundary and have a size of
346		approximately 1024 bytes */
347	0	avctx->frame_size = ((int[]){ 4096, 2736, 2048, 1640 })[c->code_size - 2];
348
349	0	return 0;
350	0	}
351
352		static int g726_encode_frame(AVCodecContext avctx, AVPacket avpkt,
353		const AVFrame frame, int got_packet_ptr)
354	0	{
355	0	G726Context *c = avctx->priv_data;
356	0	const int16_t samples = (const int16_t )frame->data[0];
357	0	PutBitContext pb;
358	0	int i, ret, out_size;
359
360	0	out_size = (frame->nb_samples * c->code_size + 7) / 8;
361	0	if ((ret = ff_get_encode_buffer(avctx, avpkt, out_size, 0)) < 0)
362	0	return ret;
363	0	init_put_bits(&pb, avpkt->data, avpkt->size);
364
365	0	for (i = 0; i < frame->nb_samples; i++)
366	0	if (c->little_endian) {
367	0	put_bits_le(&pb, c->code_size, g726_encode(c, *samples++));
368	0	} else {
369	0	put_bits(&pb, c->code_size, g726_encode(c, *samples++));
370	0	}
371
372	0	if (c->little_endian) {
373	0	flush_put_bits_le(&pb);
374	0	} else {
375	0	flush_put_bits(&pb);
376	0	}
377
378	0	*got_packet_ptr = 1;
379	0	return 0;
380	0	}
381
382		#define OFFSET(x) offsetof(G726Context, x)
383		#define AE AV_OPT_FLAG_AUDIO_PARAM \| AV_OPT_FLAG_ENCODING_PARAM
384		static const AVOption options[] = {
385		{ "code_size", "Bits per code", OFFSET(code_size), AV_OPT_TYPE_INT, { .i64 = 4 }, 2, 5, AE },
386		{ NULL },
387		};
388
389		static const AVClass g726_class = {
390		.class_name = "g726",
391		.item_name = av_default_item_name,
392		.option = options,
393		.version = LIBAVUTIL_VERSION_INT,
394		};
395
396		static const FFCodecDefault defaults[] = {
397		{ "b", "0" },
398		{ NULL },
399		};
400		#endif
401
402		#if CONFIG_ADPCM_G726_ENCODER
403		const FFCodec ff_adpcm_g726_encoder = {
404		.p.name = "g726",
405		CODEC_LONG_NAME("G.726 ADPCM"),
406		.p.type = AVMEDIA_TYPE_AUDIO,
407		.p.id = AV_CODEC_ID_ADPCM_G726,
408		.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_SMALL_LAST_FRAME \|
409		AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
410		.priv_data_size = sizeof(G726Context),
411		.init = g726_encode_init,
412		FF_CODEC_ENCODE_CB(g726_encode_frame),
413		CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16),
414		.p.priv_class = &g726_class,
415		.defaults = defaults,
416		};
417		#endif
418
419		#if CONFIG_ADPCM_G726LE_ENCODER
420		const FFCodec ff_adpcm_g726le_encoder = {
421		.p.name = "g726le",
422		CODEC_LONG_NAME("G.726 little endian ADPCM (\"right-justified\")"),
423		.p.type = AVMEDIA_TYPE_AUDIO,
424		.p.id = AV_CODEC_ID_ADPCM_G726LE,
425		.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_SMALL_LAST_FRAME \|
426		AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
427		.priv_data_size = sizeof(G726Context),
428		.init = g726_encode_init,
429		FF_CODEC_ENCODE_CB(g726_encode_frame),
430		CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16),
431		.p.priv_class = &g726_class,
432		.defaults = defaults,
433		};
434		#endif
435
436		#if CONFIG_ADPCM_G726_DECODER \|\| CONFIG_ADPCM_G726LE_DECODER
437		static av_cold int g726_decode_init(AVCodecContext *avctx)
438	1.30k	{
439	1.30k	G726Context* c = avctx->priv_data;
440
441	1.30k	if (avctx->ch_layout.nb_channels > 1){
442	214	avpriv_request_sample(avctx, "Decoding more than one channel");
443	214	return AVERROR_PATCHWELCOME;
444	214	}
445	1.08k	av_channel_layout_uninit(&avctx->ch_layout);
446	1.08k	avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
447
448	1.08k	c->little_endian = !strcmp(avctx->codec->name, "g726le");
449
450	1.08k	c->code_size = avctx->bits_per_coded_sample;
451	1.08k	if (c->code_size < 2 \|\| c->code_size > 5) {
452	206	av_log(avctx, AV_LOG_ERROR, "Invalid number of bits %d\n", c->code_size);
453	206	return AVERROR(EINVAL);
454	206	}
455	882	g726_reset(c);
456
457	882	avctx->sample_fmt = AV_SAMPLE_FMT_S16;
458	882	if (!avctx->sample_rate)
459	124	avctx->sample_rate = 8000;
460
461	882	return 0;
462	1.08k	}
463
464		static int g726_decode_frame(AVCodecContext avctx, AVFrame frame,
465		int got_frame_ptr, AVPacket avpkt)
466	278k	{
467	278k	const uint8_t *buf = avpkt->data;
468	278k	int buf_size = avpkt->size;
469	278k	G726Context *c = avctx->priv_data;
470	278k	int16_t *samples;
471	278k	GetBitContext gb;
472	278k	int out_samples, ret;
473
474	278k	out_samples = buf_size * 8 / c->code_size;
475
476		/* get output buffer */
477	278k	frame->nb_samples = out_samples;
478	278k	if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
479	0	return ret;
480	278k	samples = (int16_t *)frame->data[0];
481
482	278k	init_get_bits(&gb, buf, buf_size * 8);
483
484	97.7M	while (out_samples--)
485	97.4M	*samples++ = g726_decode(c, c->little_endian ?
486	49.5M	get_bits_le(&gb, c->code_size) :
487	97.4M	get_bits(&gb, c->code_size));
488
489	278k	if (get_bits_left(&gb) > 0)
490	40.5k	av_log(avctx, AV_LOG_ERROR, "Frame invalidly split, missing parser?\n");
491
492	278k	*got_frame_ptr = 1;
493
494	278k	return buf_size;
495	278k	}
496
497		static void g726_decode_flush(AVCodecContext *avctx)
498	84.6k	{
499	84.6k	G726Context *c = avctx->priv_data;
500	84.6k	g726_reset(c);
501	84.6k	}
502		#endif
503
504		#if CONFIG_ADPCM_G726_DECODER
505		const FFCodec ff_adpcm_g726_decoder = {
506		.p.name = "g726",
507		CODEC_LONG_NAME("G.726 ADPCM"),
508		.p.type = AVMEDIA_TYPE_AUDIO,
509		.p.id = AV_CODEC_ID_ADPCM_G726,
510		.priv_data_size = sizeof(G726Context),
511		.init = g726_decode_init,
512		FF_CODEC_DECODE_CB(g726_decode_frame),
513		.flush = g726_decode_flush,
514		.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_CHANNEL_CONF,
515		};
516		#endif
517
518		#if CONFIG_ADPCM_G726LE_DECODER
519		const FFCodec ff_adpcm_g726le_decoder = {
520		.p.name = "g726le",
521		.p.type = AVMEDIA_TYPE_AUDIO,
522		.p.id = AV_CODEC_ID_ADPCM_G726LE,
523		.priv_data_size = sizeof(G726Context),
524		.init = g726_decode_init,
525		FF_CODEC_DECODE_CB(g726_decode_frame),
526		.flush = g726_decode_flush,
527		.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_CHANNEL_CONF,
528		CODEC_LONG_NAME("G.726 ADPCM little-endian"),
529		};
530		#endif