annotate ffmpeg/libavcodec/mace.c @ 13:844d341cf643 tip

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/*
 * MACE decoder
 * Copyright (c) 2002 Laszlo Torok <[e-mail]>
 *
 * 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
 */

/**
 * @file
 * MACE decoder.
 */

#include "avcodec.h"
#include "internal.h"
#include "libavutil/common.h"

/*
 * Adapted to libavcodec by Francois Revol <[e-mail]>
 * (removed 68k REG stuff, changed types, added some statics and consts,
 * libavcodec api, context stuff, interlaced stereo out).
 */

static const int16_t MACEtab1[] = {-13, 8, 76, 222, 222, 76, 8, -13};

static const int16_t MACEtab3[] = {-18, 140, 140, -18};

static const int16_t MACEtab2[][4] = {
    {    37,    116,    206,    330}, {    39,    121,    216,    346},
    {    41,    127,    225,    361}, {    42,    132,    235,    377},
    {    44,    137,    245,    392}, {    46,    144,    256,    410},
    {    48,    150,    267,    428}, {    51,    157,    280,    449},
    {    53,    165,    293,    470}, {    55,    172,    306,    490},
    {    58,    179,    319,    511}, {    60,    187,    333,    534},
    {    63,    195,    348,    557}, {    66,    205,    364,    583},
    {    69,    214,    380,    609}, {    72,    223,    396,    635},
    {    75,    233,    414,    663}, {    79,    244,    433,    694},
    {    82,    254,    453,    725}, {    86,    265,    472,    756},
    {    90,    278,    495,    792}, {    94,    290,    516,    826},
    {    98,    303,    538,    862}, {   102,    316,    562,    901},
    {   107,    331,    588,    942}, {   112,    345,    614,    983},
    {   117,    361,    641,   1027}, {   122,    377,    670,   1074},
    {   127,    394,    701,   1123}, {   133,    411,    732,   1172},
    {   139,    430,    764,   1224}, {   145,    449,    799,   1280},
    {   152,    469,    835,   1337}, {   159,    490,    872,   1397},
    {   166,    512,    911,   1459}, {   173,    535,    951,   1523},
    {   181,    558,    993,   1590}, {   189,    584,   1038,   1663},
    {   197,    610,   1085,   1738}, {   206,    637,   1133,   1815},
    {   215,    665,   1183,   1895}, {   225,    695,   1237,   1980},
    {   235,    726,   1291,   2068}, {   246,    759,   1349,   2161},
    {   257,    792,   1409,   2257}, {   268,    828,   1472,   2357},
    {   280,    865,   1538,   2463}, {   293,    903,   1606,   2572},
    {   306,    944,   1678,   2688}, {   319,    986,   1753,   2807},
    {   334,   1030,   1832,   2933}, {   349,   1076,   1914,   3065},
    {   364,   1124,   1999,   3202}, {   380,   1174,   2088,   3344},
    {   398,   1227,   2182,   3494}, {   415,   1281,   2278,   3649},
    {   434,   1339,   2380,   3811}, {   453,   1398,   2486,   3982},
    {   473,   1461,   2598,   4160}, {   495,   1526,   2714,   4346},
    {   517,   1594,   2835,   4540}, {   540,   1665,   2961,   4741},
    {   564,   1740,   3093,   4953}, {   589,   1818,   3232,   5175},
    {   615,   1898,   3375,   5405}, {   643,   1984,   3527,   5647},
    {   671,   2072,   3683,   5898}, {   701,   2164,   3848,   6161},
    {   733,   2261,   4020,   6438}, {   766,   2362,   4199,   6724},
    {   800,   2467,   4386,   7024}, {   836,   2578,   4583,   7339},
    {   873,   2692,   4786,   7664}, {   912,   2813,   5001,   8008},
    {   952,   2938,   5223,   8364}, {   995,   3070,   5457,   8739},
    {  1039,   3207,   5701,   9129}, {  1086,   3350,   5956,   9537},
    {  1134,   3499,   6220,   9960}, {  1185,   3655,   6497,  10404},
    {  1238,   3818,   6788,  10869}, {  1293,   3989,   7091,  11355},
    {  1351,   4166,   7407,  11861}, {  1411,   4352,   7738,  12390},
    {  1474,   4547,   8084,  12946}, {  1540,   4750,   8444,  13522},
    {  1609,   4962,   8821,  14126}, {  1680,   5183,   9215,  14756},
    {  1756,   5415,   9626,  15415}, {  1834,   5657,  10057,  16104},
    {  1916,   5909,  10505,  16822}, {  2001,   6173,  10975,  17574},
    {  2091,   6448,  11463,  18356}, {  2184,   6736,  11974,  19175},
    {  2282,   7037,  12510,  20032}, {  2383,   7351,  13068,  20926},
    {  2490,   7679,  13652,  21861}, {  2601,   8021,  14260,  22834},
    {  2717,   8380,  14897,  23854}, {  2838,   8753,  15561,  24918},
    {  2965,   9144,  16256,  26031}, {  3097,   9553,  16982,  27193},
    {  3236,   9979,  17740,  28407}, {  3380,  10424,  18532,  29675},
    {  3531,  10890,  19359,  31000}, {  3688,  11375,  20222,  32382},
    {  3853,  11883,  21125,  32767}, {  4025,  12414,  22069,  32767},
    {  4205,  12967,  23053,  32767}, {  4392,  13546,  24082,  32767},
    {  4589,  14151,  25157,  32767}, {  4793,  14783,  26280,  32767},
    {  5007,  15442,  27452,  32767}, {  5231,  16132,  28678,  32767},
    {  5464,  16851,  29957,  32767}, {  5708,  17603,  31294,  32767},
    {  5963,  18389,  32691,  32767}, {  6229,  19210,  32767,  32767},
    {  6507,  20067,  32767,  32767}, {  6797,  20963,  32767,  32767},
    {  7101,  21899,  32767,  32767}, {  7418,  22876,  32767,  32767},
    {  7749,  23897,  32767,  32767}, {  8095,  24964,  32767,  32767},
    {  8456,  26078,  32767,  32767}, {  8833,  27242,  32767,  32767},
    {  9228,  28457,  32767,  32767}, {  9639,  29727,  32767,  32767}
};

static const int16_t MACEtab4[][2] = {
    {    64,    216}, {    67,    226}, {    70,    236}, {    74,    246},
    {    77,    257}, {    80,    268}, {    84,    280}, {    88,    294},
    {    92,    307}, {    96,    321}, {   100,    334}, {   104,    350},
    {   109,    365}, {   114,    382}, {   119,    399}, {   124,    416},
    {   130,    434}, {   136,    454}, {   142,    475}, {   148,    495},
    {   155,    519}, {   162,    541}, {   169,    564}, {   176,    590},
    {   185,    617}, {   193,    644}, {   201,    673}, {   210,    703},
    {   220,    735}, {   230,    767}, {   240,    801}, {   251,    838},
    {   262,    876}, {   274,    914}, {   286,    955}, {   299,    997},
    {   312,   1041}, {   326,   1089}, {   341,   1138}, {   356,   1188},
    {   372,   1241}, {   388,   1297}, {   406,   1354}, {   424,   1415},
    {   443,   1478}, {   462,   1544}, {   483,   1613}, {   505,   1684},
    {   527,   1760}, {   551,   1838}, {   576,   1921}, {   601,   2007},
    {   628,   2097}, {   656,   2190}, {   686,   2288}, {   716,   2389},
    {   748,   2496}, {   781,   2607}, {   816,   2724}, {   853,   2846},
    {   891,   2973}, {   930,   3104}, {   972,   3243}, {  1016,   3389},
    {  1061,   3539}, {  1108,   3698}, {  1158,   3862}, {  1209,   4035},
    {  1264,   4216}, {  1320,   4403}, {  1379,   4599}, {  1441,   4806},
    {  1505,   5019}, {  1572,   5244}, {  1642,   5477}, {  1715,   5722},
    {  1792,   5978}, {  1872,   6245}, {  1955,   6522}, {  2043,   6813},
    {  2134,   7118}, {  2229,   7436}, {  2329,   7767}, {  2432,   8114},
    {  2541,   8477}, {  2655,   8854}, {  2773,   9250}, {  2897,   9663},
    {  3026,  10094}, {  3162,  10546}, {  3303,  11016}, {  3450,  11508},
    {  3604,  12020}, {  3765,  12556}, {  3933,  13118}, {  4108,  13703},
    {  4292,  14315}, {  4483,  14953}, {  4683,  15621}, {  4892,  16318},
    {  5111,  17046}, {  5339,  17807}, {  5577,  18602}, {  5826,  19433},
    {  6086,  20300}, {  6358,  21205}, {  6642,  22152}, {  6938,  23141},
    {  7248,  24173}, {  7571,  25252}, {  7909,  26380}, {  8262,  27557},
    {  8631,  28786}, {  9016,  30072}, {  9419,  31413}, {  9839,  32767},
    { 10278,  32767}, { 10737,  32767}, { 11216,  32767}, { 11717,  32767},
    { 12240,  32767}, { 12786,  32767}, { 13356,  32767}, { 13953,  32767},
    { 14576,  32767}, { 15226,  32767}, { 15906,  32767}, { 16615,  32767}
};

static const struct {
    const int16_t *tab1; const int16_t *tab2; int stride;
} tabs[] = {
    {MACEtab1, &MACEtab2[0][0], 4},
    {MACEtab3, &MACEtab4[0][0], 2},
    {MACEtab1, &MACEtab2[0][0], 4}
};

#define QT_8S_2_16S(x) (((x) & 0xFF00) | (((x) >> 8) & 0xFF))

typedef struct ChannelData {
    int16_t index, factor, prev2, previous, level;
} ChannelData;

typedef struct MACEContext {
    ChannelData chd[2];
} MACEContext;

/**
 * MACE version of av_clip_int16(). We have to do this to keep binary
 * identical output to the binary decoder.
 */
static inline int16_t mace_broken_clip_int16(int n)
{
    if (n > 32767)
        return 32767;
    else if (n < -32768)
        return -32767;
    else
        return n;
}

static int16_t read_table(ChannelData *chd, uint8_t val, int tab_idx)
{
    int16_t current;

    if (val < tabs[tab_idx].stride)
        current = tabs[tab_idx].tab2[((chd->index & 0x7f0) >> 4) * tabs[tab_idx].stride + val];
    else
        current = - 1 - tabs[tab_idx].tab2[((chd->index & 0x7f0) >> 4)*tabs[tab_idx].stride + 2*tabs[tab_idx].stride-val-1];

    if (( chd->index += tabs[tab_idx].tab1[val]-(chd->index >> 5) ) < 0)
      chd->index = 0;

    return current;
}

static void chomp3(ChannelData *chd, int16_t *output, uint8_t val, int tab_idx)
{

    int16_t current = read_table(chd, val, tab_idx);

    current = mace_broken_clip_int16(current + chd->level);

    chd->level = current - (current >> 3);
    *output = QT_8S_2_16S(current);
}

static void chomp6(ChannelData *chd, int16_t *output, uint8_t val, int tab_idx)
{
    int16_t current = read_table(chd, val, tab_idx);

    if ((chd->previous ^ current) >= 0) {
        chd->factor = FFMIN(chd->factor + 506, 32767);
    } else {
        if (chd->factor - 314 < -32768)
            chd->factor = -32767;
        else
            chd->factor -= 314;
    }

    current = mace_broken_clip_int16(current + chd->level);

    chd->level = (current*chd->factor) >> 15;
    current >>= 1;

    output[0] = QT_8S_2_16S(chd->previous + chd->prev2 -
                            ((chd->prev2-current) >> 2));
    output[1] = QT_8S_2_16S(chd->previous + current +
                            ((chd->prev2-current) >> 2));
    chd->prev2 = chd->previous;
    chd->previous = current;
}

static av_cold int mace_decode_init(AVCodecContext * avctx)
{
    if (avctx->channels > 2 || avctx->channels <= 0)
        return -1;
    avctx->sample_fmt = AV_SAMPLE_FMT_S16P;

    return 0;
}

static int mace_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    AVFrame *frame     = data;
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    int16_t **samples;
    MACEContext *ctx = avctx->priv_data;
    int i, j, k, l, ret;
    int is_mace3 = (avctx->codec_id == AV_CODEC_ID_MACE3);

    /* get output buffer */
    frame->nb_samples = 3 * (buf_size << (1 - is_mace3)) / avctx->channels;
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
        return ret;
    samples = (int16_t **)frame->extended_data;

    for(i = 0; i < avctx->channels; i++) {
        int16_t *output = samples[i];

        for (j=0; j < buf_size / (avctx->channels << is_mace3); j++)
            for (k=0; k < (1 << is_mace3); k++) {
                uint8_t pkt = buf[(i << is_mace3) +
                                  (j*avctx->channels << is_mace3) + k];

                uint8_t val[2][3] = {{pkt >> 5, (pkt >> 3) & 3, pkt & 7 },
                                     {pkt & 7 , (pkt >> 3) & 3, pkt >> 5}};

                for (l=0; l < 3; l++) {
                    if (is_mace3)
                        chomp3(&ctx->chd[i], output, val[1][l], l);
                    else
                        chomp6(&ctx->chd[i], output, val[0][l], l);

                    output += 1 << (1-is_mace3);
                }
            }
    }

    *got_frame_ptr = 1;

    return buf_size;
}

AVCodec ff_mace3_decoder = {
    .name           = "mace3",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_MACE3,
    .priv_data_size = sizeof(MACEContext),
    .init           = mace_decode_init,
    .decode         = mace_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("MACE (Macintosh Audio Compression/Expansion) 3:1"),
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
                                                      AV_SAMPLE_FMT_NONE },
};

AVCodec ff_mace6_decoder = {
    .name           = "mace6",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_MACE6,
    .priv_data_size = sizeof(MACEContext),
    .init           = mace_decode_init,
    .decode         = mace_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("MACE (Macintosh Audio Compression/Expansion) 6:1"),
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
                                                      AV_SAMPLE_FMT_NONE },
};