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/*

 * MPEG-4 Audio common code

 * Copyright (c) 2008 Baptiste Coudurier 

 * Copyright (c) 2009 Alex Converse 

 *

 * 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 "get_bits.h"

#include "put_bits.h"

#include "mpeg4audio.h"

/**

 * Parse MPEG-4 audio configuration for ALS object type.

 * @param[in] gb       bit reader context

 * @param[in] c        MPEG4AudioConfig structure to fill

 * @return on success 0 is returned, otherwise a value < 0

 */

static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)

{

    if (get_bits_left(gb) < 112)

        return -1;

    if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))

        return -1;

    // override AudioSpecificConfig channel configuration and sample rate

    // which are buggy in old ALS conformance files

    c->sample_rate = get_bits_long(gb, 32);

    // skip number of samples

    skip_bits_long(gb, 32);

    // read number of channels

    c->chan_config = 0;

    c->channels    = get_bits(gb, 16) + 1;

    return 0;

}

/* XXX: make sure to update the copies in the different encoders if you change

 * this table */

const int avpriv_mpeg4audio_sample_rates[16] = {

    96000, 88200, 64000, 48000, 44100, 32000,

    24000, 22050, 16000, 12000, 11025, 8000, 7350

};

const uint8_t ff_mpeg4audio_channels[8] = {

    0, 1, 2, 3, 4, 5, 6, 8

};

static inline int get_object_type(GetBitContext *gb)

{

    int object_type = get_bits(gb, 5);

    if (object_type == AOT_ESCAPE)

        object_type = 32 + get_bits(gb, 6);

    return object_type;

}

static inline int get_sample_rate(GetBitContext *gb, int *index)

{

    *index = get_bits(gb, 4);

    return *index == 0x0f ? get_bits(gb, 24) :

        avpriv_mpeg4audio_sample_rates[*index];

}

int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,

                                 int bit_size, int sync_extension)

{

    GetBitContext gb;

    int specific_config_bitindex;

    if (bit_size <= 0 || init_get_bits(&gb, buf, bit_size) < 0)

        return AVERROR_INVALIDDATA;

    c->object_type = get_object_type(&gb);

    c->sample_rate = get_sample_rate(&gb, &c->sampling_index);

    c->chan_config = get_bits(&gb, 4);

    if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))

        c->channels = ff_mpeg4audio_channels[c->chan_config];

    c->sbr = -1;

    c->ps  = -1;

    if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&

        // check for W6132 Annex YYYY draft MP3onMP4

        !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) {

        if (c->object_type == AOT_PS)

            c->ps = 1;

        c->ext_object_type = AOT_SBR;

        c->sbr = 1;

        c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);

        c->object_type = get_object_type(&gb);

        if (c->object_type == AOT_ER_BSAC)

            c->ext_chan_config = get_bits(&gb, 4);

    } else {

        c->ext_object_type = AOT_NULL;

        c->ext_sample_rate = 0;

    }

    specific_config_bitindex = get_bits_count(&gb);

    if (c->object_type == AOT_ALS) {

        skip_bits(&gb, 5);

        if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))

            skip_bits_long(&gb, 24);

        specific_config_bitindex = get_bits_count(&gb);

        if (parse_config_ALS(&gb, c))

            return -1;

    }

    if (c->ext_object_type != AOT_SBR && sync_extension) {

        while (get_bits_left(&gb) > 15) {

            if (show_bits(&gb, 11) == 0x2b7) { // sync extension

                get_bits(&gb, 11);

                c->ext_object_type = get_object_type(&gb);

                if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) {

                    c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);

                    if (c->ext_sample_rate == c->sample_rate)

                        c->sbr = -1;

                }

                if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548)

                    c->ps = get_bits1(&gb);

                break;

            } else

                get_bits1(&gb); // skip 1 bit

        }

    }

    //PS requires SBR

    if (!c->sbr)

        c->ps = 0;

    //Limit implicit PS to the HE-AACv2 Profile

    if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)

        c->ps = 0;

    return specific_config_bitindex;

}

static av_always_inline unsigned int copy_bits(PutBitContext *pb,

                                               GetBitContext *gb,

                                               int bits)

{

    unsigned int el = get_bits(gb, bits);

    put_bits(pb, bits, el);

    return el;

}

int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)

{

    int five_bit_ch, four_bit_ch, comment_size, bits;

    int offset = put_bits_count(pb);

    copy_bits(pb, gb, 10);                  //Tag, Object Type, Frequency

    five_bit_ch  = copy_bits(pb, gb, 4);    //Front

    five_bit_ch += copy_bits(pb, gb, 4);    //Side

    five_bit_ch += copy_bits(pb, gb, 4);    //Back

    four_bit_ch  = copy_bits(pb, gb, 2);    //LFE

    four_bit_ch += copy_bits(pb, gb, 3);    //Data

    five_bit_ch += copy_bits(pb, gb, 4);    //Coupling

    if (copy_bits(pb, gb, 1))               //Mono Mixdown

        copy_bits(pb, gb, 4);

    if (copy_bits(pb, gb, 1))               //Stereo Mixdown

        copy_bits(pb, gb, 4);

    if (copy_bits(pb, gb, 1))               //Matrix Mixdown

        copy_bits(pb, gb, 3);

    for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)

        copy_bits(pb, gb, 16);

    if (bits)

        copy_bits(pb, gb, bits);

    avpriv_align_put_bits(pb);

    align_get_bits(gb);

    comment_size = copy_bits(pb, gb, 8);

    for (; comment_size > 0; comment_size--)

        copy_bits(pb, gb, 8);

    return put_bits_count(pb) - offset;

}