1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
/*
* RTP AMR Depacketizer, RFC 3267
* Copyright (c) 2010 Martin Storsjo
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "rtpdec_formats.h"
#include "libavutil/avstring.h"
static const uint8_t frame_sizes_nb[16] = {
12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
};
static const uint8_t frame_sizes_wb[16] = {
17, 23, 32, 36, 40, 46, 50, 58, 60, 5, 5, 0, 0, 0, 0, 0
};
struct PayloadContext {
int octet_align;
int crc;
int interleaving;
int channels;
};
static PayloadContext *amr_new_context(void)
{
PayloadContext *data = av_mallocz(sizeof(PayloadContext));
if(!data) return data;
data->channels = 1;
return data;
}
static void amr_free_context(PayloadContext *data)
{
av_free(data);
}
static int amr_handle_packet(AVFormatContext *ctx,
PayloadContext *data,
AVStream *st,
AVPacket * pkt,
uint32_t * timestamp,
const uint8_t * buf,
int len, int flags)
{
const uint8_t *frame_sizes = NULL;
int frames;
int i;
const uint8_t *speech_data;
uint8_t *ptr;
if (st->codec->codec_id == CODEC_ID_AMR_NB) {
frame_sizes = frame_sizes_nb;
} else if (st->codec->codec_id == CODEC_ID_AMR_WB) {
frame_sizes = frame_sizes_wb;
} else {
av_log(ctx, AV_LOG_ERROR, "Bad codec ID\n");
return AVERROR_INVALIDDATA;
}
if (st->codec->channels != 1) {
av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n");
return AVERROR_INVALIDDATA;
}
/* The AMR RTP packet consists of one header byte, followed
* by one TOC byte for each AMR frame in the packet, followed
* by the speech data for all the AMR frames.
*
* The header byte contains only a codec mode request, for
* requesting what kind of AMR data the sender wants to
* receive. Not used at the moment.
*/
/* Count the number of frames in the packet. The highest bit
* is set in a TOC byte if there are more frames following.
*/
for (frames = 1; frames < len && (buf[frames] & 0x80); frames++) ;
if (1 + frames >= len) {
/* We hit the end of the packet while counting frames. */
av_log(ctx, AV_LOG_ERROR, "No speech data found\n");
return AVERROR_INVALIDDATA;
}
speech_data = buf + 1 + frames;
/* Everything except the codec mode request byte should be output. */
if (av_new_packet(pkt, len - 1)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
ptr = pkt->data;
for (i = 0; i < frames; i++) {
uint8_t toc = buf[1 + i];
int frame_size = frame_sizes[(toc >> 3) & 0x0f];
if (speech_data + frame_size > buf + len) {
/* Too little speech data */
av_log(ctx, AV_LOG_WARNING, "Too little speech data in the RTP packet\n");
/* Set the unwritten part of the packet to zero. */
memset(ptr, 0, pkt->data + pkt->size - ptr);
pkt->size = ptr - pkt->data;
return 0;
}
/* Extract the AMR frame mode from the TOC byte */
*ptr++ = toc & 0x7C;
/* Copy the speech data */
memcpy(ptr, speech_data, frame_size);
speech_data += frame_size;
ptr += frame_size;
}
if (speech_data < buf + len) {
av_log(ctx, AV_LOG_WARNING, "Too much speech data in the RTP packet?\n");
/* Set the unwritten part of the packet to zero. */
memset(ptr, 0, pkt->data + pkt->size - ptr);
pkt->size = ptr - pkt->data;
}
return 0;
}
static int amr_parse_fmtp(AVStream *stream, PayloadContext *data,
char *attr, char *value)
{
/* Some AMR SDP configurations contain "octet-align", without
* the trailing =1. Therefore, if the value is empty,
* interpret it as "1".
*/
if (!strcmp(value, "")) {
av_log(NULL, AV_LOG_WARNING, "AMR fmtp attribute %s had "
"nonstandard empty value\n", attr);
strcpy(value, "1");
}
if (!strcmp(attr, "octet-align"))
data->octet_align = atoi(value);
else if (!strcmp(attr, "crc"))
data->crc = atoi(value);
else if (!strcmp(attr, "interleaving"))
data->interleaving = atoi(value);
else if (!strcmp(attr, "channels"))
data->channels = atoi(value);
return 0;
}
static int amr_parse_sdp_line(AVFormatContext *s, int st_index,
PayloadContext *data, const char *line)
{
const char *p;
int ret;
if (st_index < 0)
return 0;
/* Parse an fmtp line this one:
* a=fmtp:97 octet-align=1; interleaving=0
* That is, a normal fmtp: line followed by semicolon & space
* separated key/value pairs.
*/
if (av_strstart(line, "fmtp:", &p)) {
ret = ff_parse_fmtp(s->streams[st_index], data, p, amr_parse_fmtp);
if (!data->octet_align || data->crc ||
data->interleaving || data->channels != 1) {
av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n");
return -1;
}
return ret;
}
return 0;
}
RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = {
.enc_name = "AMR",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = CODEC_ID_AMR_NB,
.parse_sdp_a_line = amr_parse_sdp_line,
.alloc = amr_new_context,
.free = amr_free_context,
.parse_packet = amr_handle_packet,
};
RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler = {
.enc_name = "AMR-WB",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = CODEC_ID_AMR_WB,
.parse_sdp_a_line = amr_parse_sdp_line,
.alloc = amr_new_context,
.free = amr_free_context,
.parse_packet = amr_handle_packet,
};
|
