yading@11: /*
yading@11:  * amr file format
yading@11:  * Copyright (c) 2001 ffmpeg project
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: /*
yading@11: Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
yading@11: 
yading@11: Only mono files are supported.
yading@11: 
yading@11: */
yading@11: 
yading@11: #include "libavutil/avassert.h"
yading@11: #include "libavutil/channel_layout.h"
yading@11: #include "avformat.h"
yading@11: #include "internal.h"
yading@11: 
yading@11: static const char AMR_header[]   = "#!AMR\n";
yading@11: static const char AMRWB_header[] = "#!AMR-WB\n";
yading@11: 
yading@11: #if CONFIG_AMR_MUXER
yading@11: static int amr_write_header(AVFormatContext *s)
yading@11: {
yading@11:     AVIOContext    *pb  = s->pb;
yading@11:     AVCodecContext *enc = s->streams[0]->codec;
yading@11: 
yading@11:     s->priv_data = NULL;
yading@11: 
yading@11:     if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
yading@11:         avio_write(pb, AMR_header,   sizeof(AMR_header)   - 1); /* magic number */
yading@11:     } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
yading@11:         avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
yading@11:     } else {
yading@11:         return -1;
yading@11:     }
yading@11:     avio_flush(pb);
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
yading@11: {
yading@11:     avio_write(s->pb, pkt->data, pkt->size);
yading@11:     return 0;
yading@11: }
yading@11: #endif /* CONFIG_AMR_MUXER */
yading@11: 
yading@11: static int amr_probe(AVProbeData *p)
yading@11: {
yading@11:     // Only check for "#!AMR" which could be amr-wb, amr-nb.
yading@11:     // This will also trigger multichannel files: "#!AMR_MC1.0\n" and
yading@11:     // "#!AMR-WB_MC1.0\n" (not supported)
yading@11: 
yading@11:     if (!memcmp(p->buf, AMR_header, 5))
yading@11:         return AVPROBE_SCORE_MAX;
yading@11:     else
yading@11:         return 0;
yading@11: }
yading@11: 
yading@11: /* amr input */
yading@11: static int amr_read_header(AVFormatContext *s)
yading@11: {
yading@11:     AVIOContext *pb = s->pb;
yading@11:     AVStream *st;
yading@11:     uint8_t header[9];
yading@11: 
yading@11:     avio_read(pb, header, 6);
yading@11: 
yading@11:     st = avformat_new_stream(s, NULL);
yading@11:     if (!st)
yading@11:         return AVERROR(ENOMEM);
yading@11:     if (memcmp(header, AMR_header, 6)) {
yading@11:         avio_read(pb, header + 6, 3);
yading@11:         if (memcmp(header, AMRWB_header, 9)) {
yading@11:             return -1;
yading@11:         }
yading@11: 
yading@11:         st->codec->codec_tag   = MKTAG('s', 'a', 'w', 'b');
yading@11:         st->codec->codec_id    = AV_CODEC_ID_AMR_WB;
yading@11:         st->codec->sample_rate = 16000;
yading@11:     } else {
yading@11:         st->codec->codec_tag   = MKTAG('s', 'a', 'm', 'r');
yading@11:         st->codec->codec_id    = AV_CODEC_ID_AMR_NB;
yading@11:         st->codec->sample_rate = 8000;
yading@11:     }
yading@11:     st->codec->channels   = 1;
yading@11:     st->codec->channel_layout = AV_CH_LAYOUT_MONO;
yading@11:     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
yading@11:     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int amr_read_packet(AVFormatContext *s, AVPacket *pkt)
yading@11: {
yading@11:     AVCodecContext *enc = s->streams[0]->codec;
yading@11:     int read, size = 0, toc, mode;
yading@11:     int64_t pos = avio_tell(s->pb);
yading@11: 
yading@11:     if (url_feof(s->pb)) {
yading@11:         return AVERROR(EIO);
yading@11:     }
yading@11: 
yading@11:     // FIXME this is wrong, this should rather be in a AVParset
yading@11:     toc  = avio_r8(s->pb);
yading@11:     mode = (toc >> 3) & 0x0F;
yading@11: 
yading@11:     if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
yading@11:         static const uint8_t packed_size[16] = {
yading@11:             12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
yading@11:         };
yading@11: 
yading@11:         size = packed_size[mode] + 1;
yading@11:     } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
yading@11:         static const uint8_t packed_size[16] = {
yading@11:             18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
yading@11:         };
yading@11: 
yading@11:         size = packed_size[mode];
yading@11:     } else {
yading@11:         av_assert0(0);
yading@11:     }
yading@11: 
yading@11:     if (!size || av_new_packet(pkt, size))
yading@11:         return AVERROR(EIO);
yading@11: 
yading@11:     /* Both AMR formats have 50 frames per second */
yading@11:     s->streams[0]->codec->bit_rate = size*8*50;
yading@11: 
yading@11:     pkt->stream_index = 0;
yading@11:     pkt->pos          = pos;
yading@11:     pkt->data[0]      = toc;
yading@11:     pkt->duration     = enc->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
yading@11:     read              = avio_read(s->pb, pkt->data + 1, size - 1);
yading@11: 
yading@11:     if (read != size - 1) {
yading@11:         av_free_packet(pkt);
yading@11:         return AVERROR(EIO);
yading@11:     }
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: #if CONFIG_AMR_DEMUXER
yading@11: AVInputFormat ff_amr_demuxer = {
yading@11:     .name           = "amr",
yading@11:     .long_name      = NULL_IF_CONFIG_SMALL("3GPP AMR"),
yading@11:     .read_probe     = amr_probe,
yading@11:     .read_header    = amr_read_header,
yading@11:     .read_packet    = amr_read_packet,
yading@11:     .flags          = AVFMT_GENERIC_INDEX,
yading@11: };
yading@11: #endif
yading@11: 
yading@11: #if CONFIG_AMR_MUXER
yading@11: AVOutputFormat ff_amr_muxer = {
yading@11:     .name              = "amr",
yading@11:     .long_name         = NULL_IF_CONFIG_SMALL("3GPP AMR"),
yading@11:     .mime_type         = "audio/amr",
yading@11:     .extensions        = "amr",
yading@11:     .audio_codec       = AV_CODEC_ID_AMR_NB,
yading@11:     .video_codec       = AV_CODEC_ID_NONE,
yading@11:     .write_header      = amr_write_header,
yading@11:     .write_packet      = amr_write_packet,
yading@11: };
yading@11: #endif