94db73925eae807663c6b44c1c567dde020ede21
[libav.git] / libavformat / rtpdec_amr.c
1 /*
2 * RTP AMR Depacketizer, RFC 3267
3 * Copyright (c) 2010 Martin Storsjo
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 #include "avformat.h"
23 #include "rtpdec_amr.h"
24 #include "libavutil/avstring.h"
25
26 static const uint8_t frame_sizes_nb[16] = {
27 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
28 };
29 static const uint8_t frame_sizes_wb[16] = {
30 17, 23, 32, 36, 40, 46, 50, 58, 60, 5, 5, 0, 0, 0, 0, 0
31 };
32
33 struct PayloadContext {
34 int octet_align;
35 int crc;
36 int interleaving;
37 int channels;
38 };
39
40 static PayloadContext *amr_new_context(void)
41 {
42 PayloadContext *data = av_mallocz(sizeof(PayloadContext));
43 if(!data) return data;
44 data->channels = 1;
45 return data;
46 }
47
48 static void amr_free_context(PayloadContext *data)
49 {
50 av_free(data);
51 }
52
53 static int amr_handle_packet(AVFormatContext *ctx,
54 PayloadContext *data,
55 AVStream *st,
56 AVPacket * pkt,
57 uint32_t * timestamp,
58 const uint8_t * buf,
59 int len, int flags)
60 {
61 const uint8_t *frame_sizes = NULL;
62 int frames;
63 int i;
64 const uint8_t *speech_data;
65 uint8_t *ptr;
66
67 if (st->codec->codec_id == CODEC_ID_AMR_NB) {
68 frame_sizes = frame_sizes_nb;
69 } else if (st->codec->codec_id == CODEC_ID_AMR_WB) {
70 frame_sizes = frame_sizes_wb;
71 } else {
72 av_log(ctx, AV_LOG_ERROR, "Bad codec ID\n");
73 return AVERROR_INVALIDDATA;
74 }
75
76 if (st->codec->channels != 1) {
77 av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n");
78 return AVERROR_INVALIDDATA;
79 }
80
81 /* The AMR RTP packet consists of one header byte, followed
82 * by one TOC byte for each AMR frame in the packet, followed
83 * by the speech data for all the AMR frames.
84 *
85 * The header byte contains only a codec mode request, for
86 * requesting what kind of AMR data the sender wants to
87 * receive. Not used at the moment.
88 */
89
90 /* Count the number of frames in the packet. The highest bit
91 * is set in a TOC byte if there are more frames following.
92 */
93 for (frames = 1; frames < len && (buf[frames] & 0x80); frames++) ;
94
95 if (1 + frames >= len) {
96 /* We hit the end of the packet while counting frames. */
97 av_log(ctx, AV_LOG_ERROR, "No speech data found\n");
98 return AVERROR_INVALIDDATA;
99 }
100
101 speech_data = buf + 1 + frames;
102
103 /* Everything except the codec mode request byte should be output. */
104 if (av_new_packet(pkt, len - 1)) {
105 av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
106 return AVERROR(ENOMEM);
107 }
108 pkt->stream_index = st->index;
109 ptr = pkt->data;
110
111 for (i = 0; i < frames; i++) {
112 uint8_t toc = buf[1 + i];
113 int frame_size = frame_sizes[(toc >> 3) & 0x0f];
114
115 if (speech_data + frame_size > buf + len) {
116 /* Too little speech data */
117 av_log(ctx, AV_LOG_WARNING, "Too little speech data in the RTP packet\n");
118 /* Set the unwritten part of the packet to zero. */
119 memset(ptr, 0, pkt->data + pkt->size - ptr);
120 pkt->size = ptr - pkt->data;
121 return 0;
122 }
123
124 /* Extract the AMR frame mode from the TOC byte */
125 *ptr++ = toc & 0x7C;
126
127 /* Copy the speech data */
128 memcpy(ptr, speech_data, frame_size);
129 speech_data += frame_size;
130 ptr += frame_size;
131 }
132
133 if (speech_data < buf + len) {
134 av_log(ctx, AV_LOG_WARNING, "Too much speech data in the RTP packet?\n");
135 /* Set the unwritten part of the packet to zero. */
136 memset(ptr, 0, pkt->data + pkt->size - ptr);
137 pkt->size = ptr - pkt->data;
138 }
139
140 return 0;
141 }
142
143 static int amr_parse_fmtp(AVStream *stream, PayloadContext *data,
144 char *attr, char *value)
145 {
146 /* Some AMR SDP configurations contain "octet-align", without
147 * the trailing =1. Therefore, if the value is empty,
148 * interpret it as "1".
149 */
150 if (!strcmp(value, "")) {
151 av_log(NULL, AV_LOG_WARNING, "AMR fmtp attribute %s had "
152 "nonstandard empty value\n", attr);
153 strcpy(value, "1");
154 }
155 if (!strcmp(attr, "octet-align"))
156 data->octet_align = atoi(value);
157 else if (!strcmp(attr, "crc"))
158 data->crc = atoi(value);
159 else if (!strcmp(attr, "interleaving"))
160 data->interleaving = atoi(value);
161 else if (!strcmp(attr, "channels"))
162 data->channels = atoi(value);
163 return 0;
164 }
165
166 static int amr_parse_sdp_line(AVFormatContext *s, int st_index,
167 PayloadContext *data, const char *line)
168 {
169 const char *p;
170 int ret;
171
172 /* Parse an fmtp line this one:
173 * a=fmtp:97 octet-align=1; interleaving=0
174 * That is, a normal fmtp: line followed by semicolon & space
175 * separated key/value pairs.
176 */
177 if (av_strstart(line, "fmtp:", &p)) {
178 ret = ff_parse_fmtp(s->streams[st_index], data, p, amr_parse_fmtp);
179 if (!data->octet_align || data->crc ||
180 data->interleaving || data->channels != 1) {
181 av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n");
182 return -1;
183 }
184 return ret;
185 }
186 return 0;
187 }
188
189 RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = {
190 .enc_name = "AMR",
191 .codec_type = AVMEDIA_TYPE_AUDIO,
192 .codec_id = CODEC_ID_AMR_NB,
193 .parse_sdp_a_line = amr_parse_sdp_line,
194 .open = amr_new_context,
195 .close = amr_free_context,
196 .parse_packet = amr_handle_packet,
197 };
198
199 RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler = {
200 .enc_name = "AMR-WB",
201 .codec_type = AVMEDIA_TYPE_AUDIO,
202 .codec_id = CODEC_ID_AMR_WB,
203 .parse_sdp_a_line = amr_parse_sdp_line,
204 .open = amr_new_context,
205 .close = amr_free_context,
206 .parse_packet = amr_handle_packet,
207 };
208