1/*
2 * amr file format
3 * Copyright (c) 2001 ffmpeg project
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/*
23Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
24
25Only mono files are supported.
26
27*/
28#include "avformat.h"
29#include "internal.h"
30
31static const char AMR_header [] = "#!AMR\n";
32static const char AMRWB_header [] = "#!AMR-WB\n";
33
34#if CONFIG_AMR_MUXER
35static int amr_write_header(AVFormatContext *s)
36{
37    AVIOContext *pb = s->pb;
38    AVCodecContext *enc = s->streams[0]->codec;
39
40    s->priv_data = NULL;
41
42    if (enc->codec_id == CODEC_ID_AMR_NB)
43    {
44        avio_write(pb, AMR_header,   sizeof(AMR_header)   - 1); /* magic number */
45    }
46    else if(enc->codec_id == CODEC_ID_AMR_WB)
47    {
48        avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
49    }
50    else
51    {
52        return -1;
53    }
54    avio_flush(pb);
55    return 0;
56}
57
58static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
59{
60    avio_write(s->pb, pkt->data, pkt->size);
61    avio_flush(s->pb);
62    return 0;
63}
64#endif /* CONFIG_AMR_MUXER */
65
66static int amr_probe(AVProbeData *p)
67{
68    //Only check for "#!AMR" which could be amr-wb, amr-nb.
69    //This will also trigger multichannel files: "#!AMR_MC1.0\n" and
70    //"#!AMR-WB_MC1.0\n" (not supported)
71
72    if(memcmp(p->buf,AMR_header,5)==0)
73        return AVPROBE_SCORE_MAX;
74    else
75        return 0;
76}
77
78/* amr input */
79static int amr_read_header(AVFormatContext *s,
80                           AVFormatParameters *ap)
81{
82    AVIOContext *pb = s->pb;
83    AVStream *st;
84    uint8_t header[9];
85
86    avio_read(pb, header, 6);
87
88    st = avformat_new_stream(s, NULL);
89    if (!st)
90    {
91        return AVERROR(ENOMEM);
92    }
93    if(memcmp(header,AMR_header,6)!=0)
94    {
95        avio_read(pb, header+6, 3);
96        if(memcmp(header,AMRWB_header,9)!=0)
97        {
98            return -1;
99        }
100
101        st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');
102        st->codec->codec_id = CODEC_ID_AMR_WB;
103        st->codec->sample_rate = 16000;
104        st->codec->frame_size = 320;
105    }
106    else
107    {
108        st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');
109        st->codec->codec_id = CODEC_ID_AMR_NB;
110        st->codec->sample_rate = 8000;
111        st->codec->frame_size = 160;
112    }
113    st->codec->channels = 1;
114    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
115    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
116
117    return 0;
118}
119
120static int amr_read_packet(AVFormatContext *s,
121                          AVPacket *pkt)
122{
123    AVCodecContext *enc = s->streams[0]->codec;
124    int read, size = 0, toc, mode;
125    int64_t pos = avio_tell(s->pb);
126
127    if (s->pb->eof_reached)
128    {
129        return AVERROR(EIO);
130    }
131
132//FIXME this is wrong, this should rather be in a AVParset
133    toc=avio_r8(s->pb);
134    mode = (toc >> 3) & 0x0F;
135
136    if (enc->codec_id == CODEC_ID_AMR_NB)
137    {
138        static const uint8_t packed_size[16] = {12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0};
139
140        size=packed_size[mode]+1;
141    }
142    else if(enc->codec_id == CODEC_ID_AMR_WB)
143    {
144        static uint8_t packed_size[16] = {18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1};
145
146        size=packed_size[mode];
147    }
148    else
149    {
150        assert(0);
151    }
152
153    if ( (size==0) || av_new_packet(pkt, size))
154    {
155        return AVERROR(EIO);
156    }
157
158    /* Both AMR formats have 50 frames per second */
159    s->streams[0]->codec->bit_rate = size*8*50;
160
161    pkt->stream_index = 0;
162    pkt->pos = pos;
163    pkt->data[0]=toc;
164    pkt->duration= enc->codec_id == CODEC_ID_AMR_NB ? 160 : 320;
165    read = avio_read(s->pb, pkt->data+1, size-1);
166
167    if (read != size-1)
168    {
169        av_free_packet(pkt);
170        return AVERROR(EIO);
171    }
172
173    return 0;
174}
175
176#if CONFIG_AMR_DEMUXER
177AVInputFormat ff_amr_demuxer = {
178    .name           = "amr",
179    .long_name      = NULL_IF_CONFIG_SMALL("3GPP AMR file format"),
180    .read_probe     = amr_probe,
181    .read_header    = amr_read_header,
182    .read_packet    = amr_read_packet,
183    .flags = AVFMT_GENERIC_INDEX,
184};
185#endif
186
187#if CONFIG_AMR_MUXER
188AVOutputFormat ff_amr_muxer = {
189    .name              = "amr",
190    .long_name         = NULL_IF_CONFIG_SMALL("3GPP AMR file format"),
191    .mime_type         = "audio/amr",
192    .extensions        = "amr",
193    .audio_codec       = CODEC_ID_AMR_NB,
194    .video_codec       = CODEC_ID_NONE,
195    .write_header      = amr_write_header,
196    .write_packet      = amr_write_packet,
197};
198#endif
199