path: root/libavformat/amr.c (plain)
blob: b5194a2d9e3a7cf0d576f31507bb14774e099569

1	/*
2	* amr file format
3	* Copyright (c) 2001 FFmpeg project
4	*
5	* This file is part of FFmpeg.
6	*
7	* FFmpeg 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	* FFmpeg 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 FFmpeg; if not, write to the Free Software
19	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20	*/
21
22	/*
23	Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
24
25	Only mono files are supported.
26
27	*/
28
29	#include "libavutil/channel_layout.h"
30	#include "avformat.h"
31	#include "internal.h"
32
33	typedef struct {
34	uint64_t cumulated_size;
35	uint64_t block_count;
36	} AMRContext;
37
38	static const char AMR_header[] = "#!AMR\n";
39	static const char AMRWB_header[] = "#!AMR-WB\n";
40
41	#if CONFIG_AMR_MUXER
42	static int amr_write_header(AVFormatContext *s)
43	{
44	AVIOContext *pb = s->pb;
45	AVCodecParameters *par = s->streams[0]->codecpar;
46
47	s->priv_data = NULL;
48
49	if (par->codec_id == AV_CODEC_ID_AMR_NB) {
50	avio_write(pb, AMR_header, sizeof(AMR_header) - 1); /* magic number */
51	} else if (par->codec_id == AV_CODEC_ID_AMR_WB) {
52	avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
53	} else {
54	return -1;
55	}
56	avio_flush(pb);
57	return 0;
58	}
59
60	static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
61	{
62	avio_write(s->pb, pkt->data, pkt->size);
63	return 0;
64	}
65	#endif /* CONFIG_AMR_MUXER */
66
67	static int amr_probe(AVProbeData *p)
68	{
69	// Only check for "#!AMR" which could be amr-wb, amr-nb.
70	// This will also trigger multichannel files: "#!AMR_MC1.0\n" and
71	// "#!AMR-WB_MC1.0\n" (not supported)
72
73	if (!memcmp(p->buf, AMR_header, 5))
74	return AVPROBE_SCORE_MAX;
75	else
76	return 0;
77	}
78
79	/* amr input */
80	static int amr_read_header(AVFormatContext *s)
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	return AVERROR(ENOMEM);
91	if (memcmp(header, AMR_header, 6)) {
92	avio_read(pb, header + 6, 3);
93	if (memcmp(header, AMRWB_header, 9)) {
94	return -1;
95	}
96
97	st->codecpar->codec_tag = MKTAG('s', 'a', 'w', 'b');
98	st->codecpar->codec_id = AV_CODEC_ID_AMR_WB;
99	st->codecpar->sample_rate = 16000;
100	} else {
101	st->codecpar->codec_tag = MKTAG('s', 'a', 'm', 'r');
102	st->codecpar->codec_id = AV_CODEC_ID_AMR_NB;
103	st->codecpar->sample_rate = 8000;
104	}
105	st->codecpar->channels = 1;
106	st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
107	st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
108	avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
109
110	return 0;
111	}
112
113	static int amr_read_packet(AVFormatContext *s, AVPacket *pkt)
114	{
115	AVCodecParameters *par = s->streams[0]->codecpar;
116	int read, size = 0, toc, mode;
117	int64_t pos = avio_tell(s->pb);
118	AMRContext *amr = s->priv_data;
119
120	if (avio_feof(s->pb)) {
121	return AVERROR_EOF;
122	}
123
124	// FIXME this is wrong, this should rather be in an AVParser
125	toc = avio_r8(s->pb);
126	mode = (toc >> 3) & 0x0F;
127
128	if (par->codec_id == AV_CODEC_ID_AMR_NB) {
129	static const uint8_t packed_size[16] = {
130	12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
131	};
132
133	size = packed_size[mode] + 1;
134	} else if (par->codec_id == AV_CODEC_ID_AMR_WB) {
135	static const uint8_t packed_size[16] = {
136	18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
137	};
138
139	size = packed_size[mode];
140	}
141
142	if (!size || av_new_packet(pkt, size))
143	return AVERROR(EIO);
144
145	if (amr->cumulated_size < UINT64_MAX - size) {
146	amr->cumulated_size += size;
147	/* Both AMR formats have 50 frames per second */
148	s->streams[0]->codecpar->bit_rate = amr->cumulated_size / ++amr->block_count * 8 * 50;
149	}
150
151	pkt->stream_index = 0;
152	pkt->pos = pos;
153	pkt->data[0] = toc;
154	pkt->duration = par->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
155	read = avio_read(s->pb, pkt->data + 1, size - 1);
156
157	if (read != size - 1) {
158	av_packet_unref(pkt);
159	if (read < 0)
160	return read;
161	return AVERROR(EIO);
162	}
163
164	return 0;
165	}
166
167	#if CONFIG_AMR_DEMUXER
168	AVInputFormat ff_amr_demuxer = {
169	.name = "amr",
170	.long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
171	.priv_data_size = sizeof(AMRContext),
172	.read_probe = amr_probe,
173	.read_header = amr_read_header,
174	.read_packet = amr_read_packet,
175	.flags = AVFMT_GENERIC_INDEX,
176	};
177	#endif
178
179	#if CONFIG_AMR_MUXER
180	AVOutputFormat ff_amr_muxer = {
181	.name = "amr",
182	.long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
183	.mime_type = "audio/amr",
184	.extensions = "amr",
185	.audio_codec = AV_CODEC_ID_AMR_NB,
186	.video_codec = AV_CODEC_ID_NONE,
187	.write_header = amr_write_header,
188	.write_packet = amr_write_packet,
189	.flags = AVFMT_NOTIMESTAMPS,
190	};
191	#endif
192