/*

 * G.726 raw demuxer

 * Copyright 2017 Carl Eugen Hoyos

 *

 * 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 "avformat.h"

#include "demux.h"

#include "internal.h"

#include "libavutil/opt.h"

typedef struct G726Context {

    AVClass *class;

    int code_size;

    int sample_rate;

} G726Context;

static int g726_read_header(AVFormatContext *s)

{

    G726Context *c = s->priv_data;

    AVStream *st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);

    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codecpar->codec_id   = ffifmt(s->iformat)->raw_codec_id;

    st->codecpar->sample_rate           = c->sample_rate;

    st->codecpar->bits_per_coded_sample = c->code_size;

    st->codecpar->bit_rate              = ((int[]){ 16000, 24000, 32000, 40000 })[c->code_size - 2];

    st->codecpar->ch_layout.nb_channels = 1;

    return 0;

}

static int g726_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    int res;

    res = av_get_packet(s->pb, pkt, 1020); // a size similar to RAW_PACKET_SIZE divisible by all code_size values

    if (res < 0)

        return res;

    return 0;

}

#define OFFSET(x) offsetof(G726Context, x)

static const AVOption options[] = {

    { "code_size", "Bits per G.726 code",

        OFFSET(code_size),   AV_OPT_TYPE_INT, {.i64 =    4}, 2,       5, AV_OPT_FLAG_DECODING_PARAM },

    { "sample_rate", "",

        OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 8000}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },

    { NULL },

};

static const AVClass g726_demuxer_class = {

    .class_name     = "G.726 demuxer",

    .item_name      = av_default_item_name,

    .option         = options,

    .version        = LIBAVUTIL_VERSION_INT,

};

#if CONFIG_G726_DEMUXER

const FFInputFormat ff_g726_demuxer = {

    .p.name         = "g726",

    .p.long_name    = NULL_IF_CONFIG_SMALL("raw big-endian G.726 (\"left aligned\")"),

    .p.priv_class   = &g726_demuxer_class,

    .read_header    = g726_read_header,

    .read_packet    = g726_read_packet,

    .priv_data_size = sizeof(G726Context),

    .raw_codec_id   = AV_CODEC_ID_ADPCM_G726,

};

#endif

#if CONFIG_G726LE_DEMUXER

const FFInputFormat ff_g726le_demuxer = {

    .p.name         = "g726le",

    .p.long_name    = NULL_IF_CONFIG_SMALL("raw little-endian G.726 (\"right aligned\")"),

    .p.priv_class   = &g726_demuxer_class,

    .read_header    = g726_read_header,

    .read_packet    = g726_read_packet,

    .priv_data_size = sizeof(G726Context),

    .raw_codec_id   = AV_CODEC_ID_ADPCM_G726LE,

};

#endif