/*
  * 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 "avformat.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   = 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->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 },
 };
 
 #if CONFIG_G726_DEMUXER
 static const AVClass g726le_demuxer_class = {
     .class_name     = "G.726 big-endian demuxer",
     .item_name      = av_default_item_name,
     .option         = options,
     .version        = LIBAVUTIL_VERSION_INT,
 };
 
 AVInputFormat ff_g726_demuxer = {
     .name           = "g726",
     .long_name      = NULL_IF_CONFIG_SMALL("raw big-endian G.726 (\"left aligned\")"),
     .read_header    = g726_read_header,
     .read_packet    = g726_read_packet,
     .priv_data_size = sizeof(G726Context),
     .priv_class     = &g726le_demuxer_class,
     .raw_codec_id   = AV_CODEC_ID_ADPCM_G726,
 };
 #endif
 
 #if CONFIG_G726LE_DEMUXER
 static const AVClass g726_demuxer_class = {
     .class_name     = "G.726 little-endian demuxer",
     .item_name      = av_default_item_name,
     .option         = options,
     .version        = LIBAVUTIL_VERSION_INT,
 };
 
 AVInputFormat ff_g726le_demuxer = {
     .name           = "g726le",
     .long_name      = NULL_IF_CONFIG_SMALL("raw little-endian G.726 (\"right aligned\")"),
     .read_header    = g726_read_header,
     .read_packet    = g726_read_packet,
     .priv_data_size = sizeof(G726Context),
     .priv_class     = &g726_demuxer_class,
     .raw_codec_id   = AV_CODEC_ID_ADPCM_G726LE,
 };
 #endif