FFmpeg/libavformat/mov_chan.c

/*
 * Copyright (c) 2011 Justin Ruggles
 *
 * 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
 */

/**
 * mov 'chan' tag reading/writing.
 * @author Justin Ruggles
 */

#include <stdint.h>

#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavcodec/codec_id.h"
#include "mov_chan.h"

enum {
    c_L      = AV_CHAN_FRONT_LEFT,
    c_R      = AV_CHAN_FRONT_RIGHT,
    c_C      = AV_CHAN_FRONT_CENTER,
    c_LFE    = AV_CHAN_LOW_FREQUENCY,
    c_Rls    = AV_CHAN_BACK_LEFT,
    c_Rrs    = AV_CHAN_BACK_RIGHT,
    c_Lc     = AV_CHAN_FRONT_LEFT_OF_CENTER,
    c_Rc     = AV_CHAN_FRONT_RIGHT_OF_CENTER,
    c_Cs     = AV_CHAN_BACK_CENTER,
    c_Ls     = AV_CHAN_SIDE_LEFT,
    c_Rs     = AV_CHAN_SIDE_RIGHT,
    c_Ts     = AV_CHAN_TOP_CENTER,
    c_Vhl    = AV_CHAN_TOP_FRONT_LEFT,
    c_Vhc    = AV_CHAN_TOP_FRONT_CENTER,
    c_Vhr    = AV_CHAN_TOP_FRONT_RIGHT,
    c_Rlt    = AV_CHAN_TOP_BACK_LEFT,
    //       = AV_CHAN_TOP_BACK_CENTER,
    c_Rrt    = AV_CHAN_TOP_BACK_RIGHT,
    c_Lt     = AV_CHAN_STEREO_LEFT,
    c_Rt     = AV_CHAN_STEREO_RIGHT,
    c_Lw     = AV_CHAN_WIDE_LEFT,
    c_Rw     = AV_CHAN_WIDE_RIGHT,
    c_Lsd    = AV_CHAN_SURROUND_DIRECT_LEFT,
    c_Rsd    = AV_CHAN_SURROUND_DIRECT_RIGHT,
    c_LFE2   = AV_CHAN_LOW_FREQUENCY_2,
    //       = AV_CHAN_TOP_SIDE_LEFT,
    //       = AV_CHAN_TOP_SIDE_RIGHT,
    //       = AV_CHAN_BOTTOM_FRONT_CENTER,
    //       = AV_CHAN_BOTTOM_FRONT_LEFT,
    //       = AV_CHAN_BOTTOM_FRONT_RIGHT,
    c_W      = AV_CHAN_AMBISONIC_BASE,
    c_Y      = AV_CHAN_AMBISONIC_BASE + 1,
    c_Z      = AV_CHAN_AMBISONIC_BASE + 2,
    c_X      = AV_CHAN_AMBISONIC_BASE + 3,
    /* The following have no exact counterparts */
    c_LFE1   = AV_CHAN_LOW_FREQUENCY,
    c_Csd    = AV_CHAN_NONE,
    c_HI     = AV_CHAN_NONE,
    c_VI     = AV_CHAN_NONE,
    c_Haptic = AV_CHAN_NONE,
};

struct MovChannelLayoutMap {
    union {
        uint32_t tag;
        enum AVChannel id;
    };
};

#define TAG(_0)                                          {.tag = _0}
#define ID(_0)                                           {.id = c_##_0}
#define CHLIST(_0, ...)                                  TAG(_0), __VA_ARGS__
#define CHLIST01(_0, _1)                                 CHLIST(_0, ID(_1))
#define CHLIST02(_0, _1, _2)                             CHLIST(_0, ID(_1), ID(_2))
#define CHLIST03(_0, _1, _2, _3)                         CHLIST(_0, ID(_1), ID(_2), ID(_3))
#define CHLIST04(_0, _1, _2, _3, _4)                     CHLIST(_0, ID(_1), ID(_2), ID(_3), ID(_4))
#define CHLIST05(_0, _1, _2, _3, _4, _5)                 CHLIST(_0, ID(_1), ID(_2), ID(_3), ID(_4), ID(_5))
#define CHLIST06(_0, _1, _2, _3, _4, _5, _6)             CHLIST(_0, ID(_1), ID(_2), ID(_3), ID(_4), ID(_5), ID(_6))
#define CHLIST07(_0, _1, _2, _3, _4, _5, _6, _7)         CHLIST(_0, ID(_1), ID(_2), ID(_3), ID(_4), ID(_5), ID(_6), ID(_7))
#define CHLIST08(_0, _1, _2, _3, _4, _5, _6, _7, _8)     CHLIST(_0, ID(_1), ID(_2), ID(_3), ID(_4), ID(_5), ID(_6), ID(_7), ID(_8))
#define CHLIST09(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9) CHLIST(_0, ID(_1), ID(_2), ID(_3), ID(_4), ID(_5), ID(_6), ID(_7), ID(_8), ID(_9))
#define CHLIST16(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16) \
    CHLIST(_0, ID(_1),  ID(_2),  ID(_3),  ID(_4),  ID(_5),  ID(_6), ID(_7), ID(_8), ID(_9), ID(_10), \
               ID(_11), ID(_12), ID(_13), ID(_14), ID(_15), ID(_16))
#define CHLIST21(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21) \
    CHLIST(_0, ID(_1),  ID(_2),  ID(_3),  ID(_4),  ID(_5),  ID(_6),  ID(_7),  ID(_8),  ID(_9),  ID(_10), \
               ID(_11), ID(_12), ID(_13), ID(_14), ID(_15), ID(_16), ID(_17), ID(_18), ID(_19), ID(_20), ID(_21))

static const struct MovChannelLayoutMap mov_ch_layout_map[] = {
    CHLIST01( MOV_CH_LAYOUT_MONO,                 C ),
    CHLIST02( MOV_CH_LAYOUT_STEREO,               L,   R   ),
    CHLIST02( MOV_CH_LAYOUT_STEREOHEADPHONES,     L,   R   ),
    CHLIST02( MOV_CH_LAYOUT_BINAURAL,             L,   R   ),
    CHLIST02( MOV_CH_LAYOUT_MIDSIDE,              L,   R   ),     //C, sides
    CHLIST02( MOV_CH_LAYOUT_XY,                   L,   R   ),     //X (left ), Y (right )
    CHLIST02( MOV_CH_LAYOUT_MATRIXSTEREO,         Lt,  Rt  ),
    CHLIST02( MOV_CH_LAYOUT_AC3_1_0_1,            C,   LFE ),
    CHLIST03( MOV_CH_LAYOUT_MPEG_3_0_A,           L,   R,   C   ),
    CHLIST03( MOV_CH_LAYOUT_MPEG_3_0_B,           C,   L,   R   ),
    CHLIST03( MOV_CH_LAYOUT_AC3_3_0,              L,   C,   R   ),
    CHLIST03( MOV_CH_LAYOUT_ITU_2_1,              L,   R,   Cs  ),
    CHLIST03( MOV_CH_LAYOUT_DVD_4,                L,   R,   LFE ),
    CHLIST04( MOV_CH_LAYOUT_AMBISONIC_B_FORMAT,   W,   X,   Y,    Z   ),
    CHLIST04( MOV_CH_LAYOUT_QUADRAPHONIC,         L,   R,   Rls,  Rrs ),
    CHLIST04( MOV_CH_LAYOUT_MPEG_4_0_A,           L,   R,   C,    Cs  ),
    CHLIST04( MOV_CH_LAYOUT_MPEG_4_0_B,           C,   L,   R,    Cs  ),
    CHLIST04( MOV_CH_LAYOUT_AC3_3_1,              L,   C,   R,    Cs  ),
    CHLIST04( MOV_CH_LAYOUT_ITU_2_2,              L,   R,   Ls,   Rs  ),
    CHLIST04( MOV_CH_LAYOUT_DVD_5,                L,   R,   LFE,  Cs  ),
    CHLIST04( MOV_CH_LAYOUT_AC3_2_1_1,            L,   R,   Cs,   LFE ),
    CHLIST04( MOV_CH_LAYOUT_DVD_10,               L,   R,   C,    LFE ),
    CHLIST04( MOV_CH_LAYOUT_AC3_3_0_1,            L,   C,   R,    LFE ),
    CHLIST04( MOV_CH_LAYOUT_DTS_3_1,              C,   L,   R,    LFE ),
    CHLIST05( MOV_CH_LAYOUT_PENTAGONAL,           L,   R,   Rls,  Rrs,  C   ),
    CHLIST05( MOV_CH_LAYOUT_MPEG_5_0_A,           L,   R,   C,    Ls,   Rs  ),
    CHLIST05( MOV_CH_LAYOUT_MPEG_5_0_B,           L,   R,   Ls,   Rs,   C   ),
    CHLIST05( MOV_CH_LAYOUT_MPEG_5_0_C,           L,   C,   R,    Ls,   Rs  ),
    CHLIST05( MOV_CH_LAYOUT_MPEG_5_0_D,           C,   L,   R,    Ls,   Rs  ),
    CHLIST05( MOV_CH_LAYOUT_DVD_6,                L,   R,   LFE,  Ls,   Rs  ),
    CHLIST05( MOV_CH_LAYOUT_DVD_18,               L,   R,   Ls,   Rs,   LFE ),
    CHLIST05( MOV_CH_LAYOUT_DVD_11,               L,   R,   C,    LFE,  Cs  ),
    CHLIST05( MOV_CH_LAYOUT_AC3_3_1_1,            L,   C,   R,    Cs,   LFE ),
    CHLIST05( MOV_CH_LAYOUT_DTS_4_1,              C,   L,   R,    Cs,   LFE ),
    CHLIST06( MOV_CH_LAYOUT_HEXAGONAL,            L,   R,   Rls,  Rrs,  C,    Cs  ),
    CHLIST06( MOV_CH_LAYOUT_DTS_6_0_C,            C,   Cs,  L,    R,    Rls,  Rrs ),
    CHLIST06( MOV_CH_LAYOUT_MPEG_5_1_A,           L,   R,   C,    LFE,  Ls,   Rs  ),
    CHLIST06( MOV_CH_LAYOUT_MPEG_5_1_B,           L,   R,   Ls,   Rs,   C,    LFE ),
    CHLIST06( MOV_CH_LAYOUT_MPEG_5_1_C,           L,   C,   R,    Ls,   Rs,   LFE ),
    CHLIST06( MOV_CH_LAYOUT_MPEG_5_1_D,           C,   L,   R,    Ls,   Rs,   LFE ),
    CHLIST06( MOV_CH_LAYOUT_AUDIOUNIT_6_0,        L,   R,   Ls,   Rs,   C,    Cs  ),
    CHLIST06( MOV_CH_LAYOUT_AAC_6_0,              C,   L,   R,    Ls,   Rs,   Cs  ),
    CHLIST06( MOV_CH_LAYOUT_EAC3_6_0_A,           L,   C,   R,    Ls,   Rs,   Cs  ),
    CHLIST06( MOV_CH_LAYOUT_DTS_6_0_A,            Lc,  Rc,  L,    R,    Ls,   Rs  ),
    CHLIST06( MOV_CH_LAYOUT_DTS_6_0_B,            C,   L,   R,    Rls,  Rrs,  Ts  ),
    CHLIST07( MOV_CH_LAYOUT_MPEG_6_1_A,           L,   R,   C,    LFE,  Ls,   Rs,    Cs  ),
    CHLIST07( MOV_CH_LAYOUT_AAC_6_1,              C,   L,   R,    Ls,   Rs,   Cs,    LFE ),
    CHLIST07( MOV_CH_LAYOUT_EAC3_6_1_A,           L,   C,   R,    Ls,   Rs,   LFE,   Cs  ),
    CHLIST07( MOV_CH_LAYOUT_DTS_6_1_D,            C,   L,   R,    Ls,   Rs,   LFE,   Cs  ),
    CHLIST07( MOV_CH_LAYOUT_AUDIOUNIT_7_0,        L,   R,   Ls,   Rs,   C,    Rls,   Rrs ),
    CHLIST07( MOV_CH_LAYOUT_AAC_7_0,              C,   L,   R,    Ls,   Rs,   Rls,   Rrs ),
    CHLIST07( MOV_CH_LAYOUT_EAC3_7_0_A,           L,   C,   R,    Ls,   Rs,   Rls,   Rrs ),
    CHLIST07( MOV_CH_LAYOUT_AUDIOUNIT_7_0_FRONT,  L,   R,   Ls,   Rs,   C,    Lc,    Rc  ),
    CHLIST07( MOV_CH_LAYOUT_DTS_7_0,              Lc,  C,   Rc,   L,    R,    Ls,    Rs  ),
    CHLIST07( MOV_CH_LAYOUT_EAC3_6_1_B,           L,   C,   R,    Ls,   Rs,   LFE,   Ts  ),
    CHLIST07( MOV_CH_LAYOUT_EAC3_6_1_C,           L,   C,   R,    Ls,   Rs,   LFE,   Vhc ),
    CHLIST07( MOV_CH_LAYOUT_DTS_6_1_A,            Lc,  Rc,  L,    R,    Ls,   Rs,    LFE ),
    CHLIST07( MOV_CH_LAYOUT_DTS_6_1_B,            C,   L,   R,    Rls,  Rrs,  Ts,    LFE ),
    CHLIST07( MOV_CH_LAYOUT_DTS_6_1_C,            C,   Cs,  L,    R,    Rls,  Rrs,   LFE ),
    CHLIST08( MOV_CH_LAYOUT_OCTAGONAL,            L,   R,   Rls,  Rrs,  C,    Cs,    Ls,   Rs  ),
    CHLIST08( MOV_CH_LAYOUT_AAC_OCTAGONAL,        C,   L,   R,    Ls,   Rs,   Rls,   Rrs,  Cs  ),
    CHLIST08( MOV_CH_LAYOUT_CUBE,                 L,   R,   Rls,  Rrs,  Vhl,  Vhr,   Rlt,  Rrt ),
    CHLIST08( MOV_CH_LAYOUT_MPEG_7_1_A,           L,   R,   C,    LFE,  Ls,   Rs,    Lc,   Rc  ),
    CHLIST08( MOV_CH_LAYOUT_MPEG_7_1_B,           C,   Lc,  Rc,   L,    R,    Ls,    Rs,   LFE ),
    CHLIST08( MOV_CH_LAYOUT_EMAGIC_DEFAULT_7_1,   L,   R,   Ls,   Rs,   C,    LFE,   Lc,   Rc  ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_B,           L,   C,   R,    Ls,   Rs,   LFE,   Lc,   Rc  ),
    CHLIST08( MOV_CH_LAYOUT_DTS_7_1,              Lc,  C,   Rc,   L,    R,    Ls,    Rs,   LFE ),
    CHLIST08( MOV_CH_LAYOUT_MPEG_7_1_C,           L,   R,   C,    LFE,  Ls,   Rs,    Rls,  Rrs ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_A,           L,   C,   R,    Ls,   Rs,   LFE,   Rls,  Rrs ),
    CHLIST08( MOV_CH_LAYOUT_SMPTE_DTV,            L,   R,   C,    LFE,  Ls,   Rs,    Lt,   Rt  ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_C,           L,   C,   R,    Ls,   Rs,   LFE,   Lsd,  Rsd ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_D,           L,   C,   R,    Ls,   Rs,   LFE,   Lw,   Rw  ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_E,           L,   C,   R,    Ls,   Rs,   LFE,   Vhl,  Vhr ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_F,           L,   C,   R,    Ls,   Rs,   LFE,   Cs,   Ts  ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_G,           L,   C,   R,    Ls,   Rs,   LFE,   Cs,   Vhc ),
    CHLIST08( MOV_CH_LAYOUT_EAC3_7_1_H,           L,   C,   R,    Ls,   Rs,   LFE,   Ts,   Vhc ),
    CHLIST08( MOV_CH_LAYOUT_DTS_8_0_A,            Lc,  Rc,  L,    R,    Ls,   Rs,    Rls,  Rrs ),
    CHLIST08( MOV_CH_LAYOUT_DTS_8_0_B,            Lc,  C,   Rc,   L,    R,    Ls,    Cs,   Rs  ),
    CHLIST09( MOV_CH_LAYOUT_DTS_8_1_A,            Lc,  Rc,  L,    R,    Ls,   Rs,    Rls,  Rrs,  LFE ),
    CHLIST09( MOV_CH_LAYOUT_DTS_8_1_B,            Lc,  C,   Rc,   L,    R,    Ls,    Cs,   Rs,   LFE ),
    CHLIST16( MOV_CH_LAYOUT_TMH_10_2_STD,         L,   R,   C,    Vhc,  Lsd,  Rsd,   Ls,   Rs,   Vhl,  Vhr,  Lw,  Rw,  Csd,  Cs,  LFE1,  LFE2),
    CHLIST21( MOV_CH_LAYOUT_TMH_10_2_FULL,        L,   R,   C,    Vhc,  Lsd,  Rsd,   Ls,   Rs,   Vhl,  Vhr,  Lw,  Rw,  Csd,  Cs,  LFE1,  LFE2,  Lc,  Rc,  HI,  VI,  Haptic),
};

static const enum MovChannelLayoutTag mov_ch_layouts_aac[] = {
    MOV_CH_LAYOUT_MONO,
    MOV_CH_LAYOUT_STEREO,
    MOV_CH_LAYOUT_AC3_1_0_1,
    MOV_CH_LAYOUT_MPEG_3_0_B,
    MOV_CH_LAYOUT_ITU_2_1,
    MOV_CH_LAYOUT_DVD_4,
    MOV_CH_LAYOUT_QUADRAPHONIC,
    MOV_CH_LAYOUT_MPEG_4_0_B,
    MOV_CH_LAYOUT_ITU_2_2,
    MOV_CH_LAYOUT_AC3_2_1_1,
    MOV_CH_LAYOUT_DTS_3_1,
    MOV_CH_LAYOUT_MPEG_5_0_D,
    MOV_CH_LAYOUT_DVD_18,
    MOV_CH_LAYOUT_DTS_4_1,
    MOV_CH_LAYOUT_MPEG_5_1_D,
    MOV_CH_LAYOUT_AAC_6_0,
    MOV_CH_LAYOUT_DTS_6_0_A,
    MOV_CH_LAYOUT_AAC_6_1,
    MOV_CH_LAYOUT_AAC_7_0,
    MOV_CH_LAYOUT_DTS_6_1_A,
    MOV_CH_LAYOUT_AAC_OCTAGONAL,
    MOV_CH_LAYOUT_MPEG_7_1_B,
    MOV_CH_LAYOUT_DTS_8_0_A,
    0,
};

static const enum MovChannelLayoutTag mov_ch_layouts_ac3[] = {
    MOV_CH_LAYOUT_MONO,
    MOV_CH_LAYOUT_STEREO,
    MOV_CH_LAYOUT_AC3_1_0_1,
    MOV_CH_LAYOUT_AC3_3_0,
    MOV_CH_LAYOUT_ITU_2_1,
    MOV_CH_LAYOUT_DVD_4,
    MOV_CH_LAYOUT_AC3_3_1,
    MOV_CH_LAYOUT_ITU_2_2,
    MOV_CH_LAYOUT_AC3_2_1_1,
    MOV_CH_LAYOUT_AC3_3_0_1,
    MOV_CH_LAYOUT_MPEG_5_0_C,
    MOV_CH_LAYOUT_DVD_18,
    MOV_CH_LAYOUT_AC3_3_1_1,
    MOV_CH_LAYOUT_MPEG_5_1_C,
    0,
};

static const enum MovChannelLayoutTag mov_ch_layouts_alac[] = {
    MOV_CH_LAYOUT_MONO,
    MOV_CH_LAYOUT_STEREO,
    MOV_CH_LAYOUT_MPEG_3_0_B,
    MOV_CH_LAYOUT_MPEG_4_0_B,
    MOV_CH_LAYOUT_MPEG_5_0_D,
    MOV_CH_LAYOUT_MPEG_5_1_D,
    MOV_CH_LAYOUT_AAC_6_1,
    MOV_CH_LAYOUT_MPEG_7_1_B,
    0,
};

static const enum MovChannelLayoutTag mov_ch_layouts_wav[] = {
    MOV_CH_LAYOUT_MONO,
    MOV_CH_LAYOUT_STEREO,
    MOV_CH_LAYOUT_MATRIXSTEREO,
    MOV_CH_LAYOUT_MPEG_3_0_A,
    MOV_CH_LAYOUT_QUADRAPHONIC,
    MOV_CH_LAYOUT_MPEG_5_0_A,
    MOV_CH_LAYOUT_MPEG_5_1_A,
    MOV_CH_LAYOUT_MPEG_6_1_A,
    MOV_CH_LAYOUT_MPEG_7_1_A,
    MOV_CH_LAYOUT_MPEG_7_1_C,
    MOV_CH_LAYOUT_SMPTE_DTV,
    0,
};

static const struct {
    enum AVCodecID codec_id;
    const enum MovChannelLayoutTag *layouts;
} mov_codec_ch_layouts[] = {
    { AV_CODEC_ID_AAC,     mov_ch_layouts_aac      },
    { AV_CODEC_ID_AC3,     mov_ch_layouts_ac3      },
    { AV_CODEC_ID_ALAC,    mov_ch_layouts_alac     },
    { AV_CODEC_ID_PCM_U8,    mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S8,    mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S16LE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S16BE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S24LE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S24BE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S32LE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_S32BE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_F32LE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_F32BE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_F64LE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_PCM_F64BE, mov_ch_layouts_wav    },
    { AV_CODEC_ID_NONE,    NULL                    },
};

static const struct MovChannelLayoutMap* find_layout_map(uint32_t tag)
{
#if defined(ASSERT_LEVEL) && ASSERT_LEVEL > 1
    {
        int i;
        for (i = 0; i < FF_ARRAY_ELEMS(mov_ch_layout_map); i += 1 + (mov_ch_layout_map[i].tag & 0xffff))
            av_assert2(mov_ch_layout_map[i].tag & 0xffff0000);
        av_assert2(i == FF_ARRAY_ELEMS(mov_ch_layout_map));
    }
#endif
    for (int i = 0; i < FF_ARRAY_ELEMS(mov_ch_layout_map); i += 1 + (mov_ch_layout_map[i].tag & 0xffff))
        if (mov_ch_layout_map[i].tag == tag)
            return &mov_ch_layout_map[i + 1];
    return NULL;
}

/**
 * Get the channel layout for the specified non-special channel layout tag if
 * known.
 *
 * @param[in,out]  ch_layout  channel layout
 * @param[in]      tag        channel layout tag
 * @return                    <0 on error
 */
static int mov_get_channel_layout(AVChannelLayout *ch_layout, uint32_t tag)
{
    int i, channels;
    const struct MovChannelLayoutMap *layout_map;

    channels = tag & 0xFFFF;

    /* find the channel layout for the specified layout tag */
    layout_map = find_layout_map(tag);
    if (layout_map) {
        int ret;
        av_channel_layout_uninit(ch_layout);
        ret = av_channel_layout_custom_init(ch_layout, channels);
        if (ret < 0)
            return ret;
        for (i = 0; i < channels; i++) {
            enum AVChannel id = layout_map[i].id;
            ch_layout->u.map[i].id = (id != AV_CHAN_NONE ? id : AV_CHAN_UNKNOWN);
        }
        return av_channel_layout_retype(ch_layout, 0, AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL);
    }
    return 0;
}

static enum AVChannel mov_get_channel_id(uint32_t label)
{
    if (label == 0)
        return AV_CHAN_UNUSED;
    if (label <= 18)
        return (label - 1);
    if (label == 35)
        return AV_CHAN_WIDE_LEFT;
    if (label == 36)
        return AV_CHAN_WIDE_RIGHT;
    if (label == 37)
        return AV_CHAN_LOW_FREQUENCY_2;
    if (label == 38)
        return AV_CHAN_STEREO_LEFT;
    if (label == 39)
        return AV_CHAN_STEREO_RIGHT;
    return AV_CHAN_UNKNOWN;
}

static uint32_t mov_get_channel_label(enum AVChannel channel)
{
    if (channel < 0)
        return 0;
    if (channel <= AV_CHAN_TOP_BACK_RIGHT)
        return channel + 1;
    if (channel == AV_CHAN_WIDE_LEFT)
        return 35;
    if (channel == AV_CHAN_WIDE_RIGHT)
        return 36;
    if (channel == AV_CHAN_LOW_FREQUENCY_2)
        return 37;
    if (channel == AV_CHAN_STEREO_LEFT)
        return 38;
    if (channel == AV_CHAN_STEREO_RIGHT)
        return 39;
    return 0;
}

int ff_mov_get_channel_layout_tag(const AVCodecParameters *par,
                                  uint32_t *layout,
                                  uint32_t *bitmap,
                                  uint32_t **pchannel_desc)
{
    int i, j;
    uint32_t tag = 0;
    const enum MovChannelLayoutTag *layouts = NULL;

    /* find the layout list for the specified codec */
    for (i = 0; mov_codec_ch_layouts[i].codec_id != AV_CODEC_ID_NONE; i++) {
        if (mov_codec_ch_layouts[i].codec_id == par->codec_id)
            break;
    }
    if (mov_codec_ch_layouts[i].codec_id != AV_CODEC_ID_NONE)
        layouts = mov_codec_ch_layouts[i].layouts;

    if (layouts) {
        int channels;
        const struct MovChannelLayoutMap *layout_map;

        /* get the layout map based on the channel count */
        channels = par->ch_layout.nb_channels;

        /* find the layout tag for the specified channel layout */
        for (i = 0; layouts[i] != 0; i++) {
            if ((layouts[i] & 0xFFFF) != channels)
                continue;
            layout_map = find_layout_map(layouts[i]);
            if (layout_map) {
                for (j = 0; j < channels; j++) {
                    if (av_channel_layout_channel_from_index(&par->ch_layout, j) != layout_map[j].id)
                        break;
                }
                if (j == channels)
                    break;
            }
        }
        tag = layouts[i];
    }

    *layout = tag;
    *bitmap = 0;
    *pchannel_desc = NULL;

    /* if no tag was found, use channel bitmap or description as a backup if possible */
    if (tag == 0) {
        uint32_t *channel_desc;
        if (par->ch_layout.order == AV_CHANNEL_ORDER_NATIVE &&
            par->ch_layout.u.mask < 0x40000) {
            *layout = MOV_CH_LAYOUT_USE_BITMAP;
            *bitmap = (uint32_t)par->ch_layout.u.mask;
            return 0;
        } else if (par->ch_layout.order == AV_CHANNEL_ORDER_UNSPEC)
            return AVERROR(ENOSYS);

        channel_desc = av_malloc_array(par->ch_layout.nb_channels, sizeof(*channel_desc));
        if (!channel_desc)
            return AVERROR(ENOMEM);

        for (i = 0; i < par->ch_layout.nb_channels; i++) {
            channel_desc[i] =
                mov_get_channel_label(av_channel_layout_channel_from_index(&par->ch_layout, i));

            if (channel_desc[i] == 0) {
                av_free(channel_desc);
                return AVERROR(ENOSYS);
            }
        }

        *pchannel_desc = channel_desc;
    }

    return 0;
}

int ff_mov_read_chan(AVFormatContext *s, AVIOContext *pb, AVStream *st,
                     int64_t size)
{
    uint32_t layout_tag, bitmap, num_descr;
    int ret;
    AVChannelLayout *ch_layout = &st->codecpar->ch_layout;

    if (size < 12)
        return AVERROR_INVALIDDATA;

    layout_tag = avio_rb32(pb);
    bitmap     = avio_rb32(pb);
    num_descr  = avio_rb32(pb);

    av_log(s, AV_LOG_DEBUG, "chan: layout=%"PRIu32" "
           "bitmap=%"PRIu32" num_descr=%"PRIu32"\n",
           layout_tag, bitmap, num_descr);

    if (size < 12ULL + num_descr * 20ULL)
        return 0;

    if (layout_tag == MOV_CH_LAYOUT_USE_DESCRIPTIONS) {
        int nb_channels = ch_layout->nb_channels ? ch_layout->nb_channels : num_descr;
        if (num_descr > nb_channels) {
            av_log(s, AV_LOG_WARNING, "got %d channel descriptions, capping to the number of channels %d\n",
                   num_descr, nb_channels);
            num_descr = nb_channels;
        }

        av_channel_layout_uninit(ch_layout);
        ret = av_channel_layout_custom_init(ch_layout, nb_channels);
        if (ret < 0)
            goto out;

        for (int i = 0; i < num_descr; i++) {
            uint32_t label;
            if (pb->eof_reached) {
                av_log(s, AV_LOG_ERROR,
                       "reached EOF while reading channel layout\n");
                return AVERROR_INVALIDDATA;
            }
            label     = avio_rb32(pb);          // mChannelLabel
            avio_rb32(pb);                      // mChannelFlags
            avio_rl32(pb);                      // mCoordinates[0]
            avio_rl32(pb);                      // mCoordinates[1]
            avio_rl32(pb);                      // mCoordinates[2]
            size -= 20;
            ch_layout->u.map[i].id = mov_get_channel_id(label);
        }

        ret = av_channel_layout_retype(ch_layout, 0, AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL);
        if (ret < 0)
            goto out;
    } else if (layout_tag == MOV_CH_LAYOUT_USE_BITMAP) {
        if (!ch_layout->nb_channels || av_popcount(bitmap) == ch_layout->nb_channels) {
            if (bitmap < 0x40000) {
                av_channel_layout_uninit(ch_layout);
                av_channel_layout_from_mask(ch_layout, bitmap);
            }
        } else {
            av_log(s, AV_LOG_WARNING, "ignoring channel layout bitmap with %d channels because number of channels is %d\n",
                   av_popcount64(bitmap), ch_layout->nb_channels);
        }
    } else if (layout_tag & 0xFFFF) {
        int nb_channels = layout_tag & 0xFFFF;
        if (!ch_layout->nb_channels)
            ch_layout->nb_channels = nb_channels;
        if (nb_channels == ch_layout->nb_channels) {
            ret = mov_get_channel_layout(ch_layout, layout_tag);
            if (ret < 0)
                return ret;
        } else {
            av_log(s, AV_LOG_WARNING, "ignoring layout tag with %d channels because number of channels is %d\n",
                   nb_channels, ch_layout->nb_channels);
        }
    }
    ret = 0;

out:
    avio_skip(pb, size - 12);

    return ret;
}

/* ISO/IEC 23001-8, 8.2 */
static const AVChannelLayout iso_channel_configuration[] = {
    // 0: any setup
    {0},

    // 1: centre front
    AV_CHANNEL_LAYOUT_MONO,

    // 2: left front, right front
    AV_CHANNEL_LAYOUT_STEREO,

    // 3: centre front, left front, right front
    AV_CHANNEL_LAYOUT_SURROUND,

    // 4: centre front, left front, right front, rear centre
    AV_CHANNEL_LAYOUT_4POINT0,

    // 5: centre front, left front, right front, left surround, right surround
    AV_CHANNEL_LAYOUT_5POINT0,

    // 6: 5 + LFE
    AV_CHANNEL_LAYOUT_5POINT1,

    // 7: centre front, left front centre, right front centre,
    // left front, right front, left surround, right surround, LFE
    AV_CHANNEL_LAYOUT_7POINT1_WIDE,

    // 8: channel1, channel2
    AV_CHANNEL_LAYOUT_STEREO_DOWNMIX,

    // 9: left front, right front, rear centre
    AV_CHANNEL_LAYOUT_2_1,

    // 10: left front, right front, left surround, right surround
    AV_CHANNEL_LAYOUT_2_2,

    // 11: centre front, left front, right front, left surround, right surround, rear centre, LFE
    AV_CHANNEL_LAYOUT_6POINT1,

    // 12: centre front, left front, right front
    // left surround, right surround
    // rear surround left, rear surround right
    // LFE
    AV_CHANNEL_LAYOUT_7POINT1,

    // 13:
    AV_CHANNEL_LAYOUT_22POINT2,

    // 14:
    AV_CHANNEL_LAYOUT_7POINT1_TOP_BACK,

    // TODO: 15 - 20
};

/* ISO/IEC 23001-8, table 8 */
static const enum AVChannel iso_channel_position[] = {
    // 0: left front
    AV_CHAN_FRONT_LEFT,

    // 1: right front
    AV_CHAN_FRONT_RIGHT,

    // 2: centre front
    AV_CHAN_FRONT_CENTER,

    // 3: low frequence enhancement
    AV_CHAN_LOW_FREQUENCY,

    // 4: left surround
    // TODO
    AV_CHAN_NONE,

    // 5: right surround
    // TODO
    AV_CHAN_NONE,

    // 6: left front centre
    AV_CHAN_FRONT_LEFT_OF_CENTER,

    // 7: right front centre
    AV_CHAN_FRONT_RIGHT_OF_CENTER,

    // 8: rear surround left
    AV_CHAN_BACK_LEFT,

    // 9: rear surround right
    AV_CHAN_BACK_RIGHT,

    // 10: rear centre
    AV_CHAN_BACK_CENTER,

    // 11: left surround direct
    AV_CHAN_SURROUND_DIRECT_LEFT,

    // 12: right surround direct
    AV_CHAN_SURROUND_DIRECT_RIGHT,

    // 13: left side surround
    AV_CHAN_SIDE_LEFT,

    // 14: right side surround
    AV_CHAN_SIDE_RIGHT,

    // 15: left wide front
    AV_CHAN_WIDE_LEFT,

    // 16: right wide front
    AV_CHAN_WIDE_RIGHT,

    // 17: left front vertical height
    AV_CHAN_TOP_FRONT_LEFT,

    // 18: right front vertical height
    AV_CHAN_TOP_FRONT_RIGHT,

    // 19: centre front vertical height
    AV_CHAN_TOP_FRONT_CENTER,

    // 20: left surround vertical height rear
    AV_CHAN_TOP_BACK_LEFT,

    // 21: right surround vertical height rear
    AV_CHAN_TOP_BACK_RIGHT,

    // 22: centre vertical height rear
    AV_CHAN_TOP_BACK_CENTER,

    // 23: left vertical height side surround
    AV_CHAN_TOP_SIDE_LEFT,

    // 24: right vertical height side surround
    AV_CHAN_TOP_SIDE_RIGHT,

    // 25: top centre surround
    AV_CHAN_TOP_CENTER,

    // 26: low frequency enhancement 2
    AV_CHAN_LOW_FREQUENCY_2,

    // 27: left front vertical bottom
    AV_CHAN_BOTTOM_FRONT_LEFT,

    // 28: right front vertical bottom
    AV_CHAN_BOTTOM_FRONT_RIGHT,

    // 29: centre front vertical bottom
    AV_CHAN_BOTTOM_FRONT_CENTER,

    // 30: left vertical height surround
    // TODO
    AV_CHAN_NONE,

    // 31: right vertical height surround
    // TODO
    AV_CHAN_NONE,

    // 32, 33, 34, 35, reserved
    AV_CHAN_NONE,
    AV_CHAN_NONE,
    AV_CHAN_NONE,
    AV_CHAN_NONE,

    // 36: low frequency enhancement 3
    AV_CHAN_NONE,

    // 37: left edge of screen
    AV_CHAN_NONE,
    // 38: right edge of screen
    AV_CHAN_NONE,
    // 39: half-way between centre of screen and left edge of screen
    AV_CHAN_NONE,
    // 40: half-way between centre of screen and right edge of screen
    AV_CHAN_NONE,

    // 41: left back surround
    AV_CHAN_NONE,

    // 42: right back surround
    AV_CHAN_NONE,

    // 43 - 125: reserved
    // 126: explicit position
    // 127: unknown /undefined
};

int ff_mov_get_channel_config_from_layout(const AVChannelLayout *layout, int *config)
{
    // Set default value which means any setup in 23001-8
    *config = 0;
    for (int i = 0; i < FF_ARRAY_ELEMS(iso_channel_configuration); i++) {
        if (!av_channel_layout_compare(layout, iso_channel_configuration + i)) {
            *config = i;
            break;
        }
    }

    return 0;
}

int ff_mov_get_channel_layout_from_config(int config, AVChannelLayout *layout)
{
    if (config > 0 && config < FF_ARRAY_ELEMS(iso_channel_configuration)) {
        av_channel_layout_copy(layout, &iso_channel_configuration[config]);
        return 0;
    }

    return -1;
}

int ff_mov_get_channel_positions_from_layout(const AVChannelLayout *layout,
                                             uint8_t *position, int position_num)
{
    enum AVChannel channel;

    if (position_num < layout->nb_channels)
        return AVERROR(EINVAL);

    for (int i = 0; i < layout->nb_channels; i++) {
        position[i] = 127;
        channel = av_channel_layout_channel_from_index(layout, i);
        if (channel == AV_CHAN_NONE)
            return AVERROR(EINVAL);

        for (int j = 0; j < FF_ARRAY_ELEMS(iso_channel_position); j++) {
            if (iso_channel_position[j] == channel) {
                position[i] = j;
                break;
            }
        }
        if (position[i] == 127)
            return AVERROR(EINVAL);
    }

    return 0;
}

int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st)
{
    int stream_structure = avio_r8(pb);
    int ret;

    // stream carries channels
    if (stream_structure & 1) {
        int layout = avio_r8(pb);

        av_log(s, AV_LOG_TRACE, "'chnl' layout %d\n", layout);
        if (!layout) {
            AVChannelLayout *ch_layout = &st->codecpar->ch_layout;
            int nb_channels = ch_layout->nb_channels;

            av_channel_layout_uninit(ch_layout);
            ret = av_channel_layout_custom_init(ch_layout, nb_channels);
            if (ret < 0)
                return ret;

            for (int i = 0; i < nb_channels; i++) {
                int speaker_pos = avio_r8(pb);
                enum AVChannel channel;

                if (speaker_pos == 126) // explicit position
                    avio_skip(pb, 3);   // azimuth, elevation

                if (speaker_pos >= FF_ARRAY_ELEMS(iso_channel_position))
                    channel = AV_CHAN_NONE;
                else
                    channel = iso_channel_position[speaker_pos];

                if (channel == AV_CHAN_NONE) {
                    av_log(s, AV_LOG_WARNING, "speaker position %d is not implemented\n", speaker_pos);
                    channel = AV_CHAN_UNKNOWN;
                }

                ch_layout->u.map[i].id = channel;
            }

            ret = av_channel_layout_retype(ch_layout, 0, AV_CHANNEL_LAYOUT_RETYPE_FLAG_CANONICAL);
            if (ret < 0)
                return ret;
        } else {
            uint64_t omitted_channel_map = avio_rb64(pb);

            if (omitted_channel_map) {
                avpriv_request_sample(s, "omitted_channel_map 0x%" PRIx64 " != 0",
                                      omitted_channel_map);
                return AVERROR_PATCHWELCOME;
            }
            ff_mov_get_channel_layout_from_config(layout, &st->codecpar->ch_layout);
        }
    }

    // stream carries objects
    if (stream_structure & 2) {
        int obj_count = avio_r8(pb);
        av_log(s, AV_LOG_TRACE, "'chnl' with object_count %d\n", obj_count);
    }

    return 0;
}