libavcodec/g726.c - play-games/ffmpeg - Git at Google


            
            /*

            
             * 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_mod_uintp2(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),

            
                .p.sample_fmts  = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,

            
                                                                 AV_SAMPLE_FMT_NONE },

            
                .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),

            
                .p.sample_fmts  = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,

            
                                                                 AV_SAMPLE_FMT_NONE },

            
                .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;


                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
	/*
	* 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] += 128pk0c->pk[1] + fa1 - (c->a[1]>>7);
	c->a[1] = av_clip(c->a[1], -12288, 12288);
	c->a[0] += 643pk0*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] += 128dq0sgn(-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_mod_uintp2(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),
	.p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
	AV_SAMPLE_FMT_NONE },
	.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),
	.p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
	AV_SAMPLE_FMT_NONE },
	.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;

	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