/*

  * amr file format
  * Copyright (c) 2001 ffmpeg project
  *

  * 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

  */
 
 /*
 Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
 

 Only mono files are supported.

 
 */

 
 #include "libavutil/channel_layout.h"

 #include "avformat.h"

 #include "internal.h"

 typedef struct {
     uint64_t cumulated_size;
     uint64_t block_count;
 } AMRContext;
 

 static const char AMR_header[]   = "#!AMR\n";
 static const char AMRWB_header[] = "#!AMR-WB\n";

 #if CONFIG_AMR_MUXER

 static int amr_write_header(AVFormatContext *s)
 {

     AVIOContext    *pb  = s->pb;

     AVCodecContext *enc = s->streams[0]->codec;

 
     s->priv_data = NULL;
 

     if (enc->codec_id == AV_CODEC_ID_AMR_NB) {

         avio_write(pb, AMR_header,   sizeof(AMR_header)   - 1); /* magic number */

     } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {

         avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */

     } else {

         return -1;

     }

     avio_flush(pb);

     return 0;
 }
 

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

 {

     avio_write(s->pb, pkt->data, pkt->size);

     return 0;
 }

 #endif /* CONFIG_AMR_MUXER */

 
 static int amr_probe(AVProbeData *p)
 {

     // Only check for "#!AMR" which could be amr-wb, amr-nb.
     // This will also trigger multichannel files: "#!AMR_MC1.0\n" and
     // "#!AMR-WB_MC1.0\n" (not supported)

     if (!memcmp(p->buf, AMR_header, 5))

         return AVPROBE_SCORE_MAX;
     else
         return 0;
 }
 
 /* amr input */

 static int amr_read_header(AVFormatContext *s)

 {

     AVIOContext *pb = s->pb;

     AVStream *st;

     uint8_t header[9];

     avio_read(pb, header, 6);

     st = avformat_new_stream(s, NULL);

     if (!st)

         return AVERROR(ENOMEM);

     if (memcmp(header, AMR_header, 6)) {
         avio_read(pb, header + 6, 3);
         if (memcmp(header, AMRWB_header, 9)) {

             return -1;
         }

         st->codec->codec_tag   = MKTAG('s', 'a', 'w', 'b');

         st->codec->codec_id    = AV_CODEC_ID_AMR_WB;

         st->codec->sample_rate = 16000;

     } else {
         st->codec->codec_tag   = MKTAG('s', 'a', 'm', 'r');

         st->codec->codec_id    = AV_CODEC_ID_AMR_NB;

         st->codec->sample_rate = 8000;

     }

     st->codec->channels   = 1;

     st->codec->channel_layout = AV_CH_LAYOUT_MONO;

     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);

 
     return 0;
 }
 

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

 {

     AVCodecContext *enc = s->streams[0]->codec;

     int read, size = 0, toc, mode;

     int64_t pos = avio_tell(s->pb);

     AMRContext *amr = s->priv_data;

     if (avio_feof(s->pb)) {

         return AVERROR(EIO);

     }

     // FIXME this is wrong, this should rather be in a AVParser

     toc  = avio_r8(s->pb);

     mode = (toc >> 3) & 0x0F;

     if (enc->codec_id == AV_CODEC_ID_AMR_NB) {

         static const uint8_t packed_size[16] = {
             12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
         };

         size = packed_size[mode] + 1;

     } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {

         static const uint8_t packed_size[16] = {

             18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
         };

         size = packed_size[mode];

     }

     if (!size || av_new_packet(pkt, size))

         return AVERROR(EIO);

     if (amr->cumulated_size < UINT64_MAX - size) {
         amr->cumulated_size += size;
         /* Both AMR formats have 50 frames per second */
         s->streams[0]->codec->bit_rate = amr->cumulated_size / ++amr->block_count * 8 * 50;
     }

     pkt->stream_index = 0;

     pkt->pos          = pos;
     pkt->data[0]      = toc;

     pkt->duration     = enc->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;

     read              = avio_read(s->pb, pkt->data + 1, size - 1);

     if (read != size - 1) {

         av_free_packet(pkt);

         return AVERROR(EIO);

     }
 

     return 0;

 }
 

 #if CONFIG_AMR_DEMUXER

 AVInputFormat ff_amr_demuxer = {

     .name           = "amr",

     .long_name      = NULL_IF_CONFIG_SMALL("3GPP AMR"),

     .priv_data_size = sizeof(AMRContext),

     .read_probe     = amr_probe,
     .read_header    = amr_read_header,
     .read_packet    = amr_read_packet,

     .flags          = AVFMT_GENERIC_INDEX,

 };

 #endif

 #if CONFIG_AMR_MUXER

 AVOutputFormat ff_amr_muxer = {

     .name              = "amr",

     .long_name         = NULL_IF_CONFIG_SMALL("3GPP AMR"),

     .mime_type         = "audio/amr",
     .extensions        = "amr",

     .audio_codec       = AV_CODEC_ID_AMR_NB,
     .video_codec       = AV_CODEC_ID_NONE,

     .write_header      = amr_write_header,
     .write_packet      = amr_write_packet,

     .flags             = AVFMT_NOTIMESTAMPS,

 };

 #endif