FFmpeg
rtpdec_amr.c
Go to the documentation of this file.
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 
23 #include "avformat.h"
24 #include "rtpdec_formats.h"
25 #include "libavutil/avstring.h"
26 
27 static const uint8_t frame_sizes_nb[16] = {
28  12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
29 };
30 static const uint8_t frame_sizes_wb[16] = {
31  17, 23, 32, 36, 40, 46, 50, 58, 60, 5, 5, 0, 0, 0, 0, 0
32 };
33 
34 struct PayloadContext {
36  int crc;
38  int channels;
39 };
40 
41 static av_cold int amr_init(AVFormatContext *s, int st_index, PayloadContext *data)
42 {
43  data->channels = 1;
44  return 0;
45 }
46 
48  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
49  const uint8_t *buf, int len, uint16_t seq,
50  int flags)
51 {
52  const uint8_t *frame_sizes = NULL;
53  int frames;
54  int i;
55  const uint8_t *speech_data;
56  uint8_t *ptr;
57 
58  if (st->codecpar->codec_id == AV_CODEC_ID_AMR_NB) {
59  frame_sizes = frame_sizes_nb;
60  } else if (st->codecpar->codec_id == AV_CODEC_ID_AMR_WB) {
61  frame_sizes = frame_sizes_wb;
62  } else {
63  av_log(ctx, AV_LOG_ERROR, "Bad codec ID\n");
64  return AVERROR_INVALIDDATA;
65  }
66 
67  if (st->codecpar->channels != 1) {
68  av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n");
69  return AVERROR_INVALIDDATA;
70  }
72 
73  /* The AMR RTP packet consists of one header byte, followed
74  * by one TOC byte for each AMR frame in the packet, followed
75  * by the speech data for all the AMR frames.
76  *
77  * The header byte contains only a codec mode request, for
78  * requesting what kind of AMR data the sender wants to
79  * receive. Not used at the moment.
80  */
81 
82  /* Count the number of frames in the packet. The highest bit
83  * is set in a TOC byte if there are more frames following.
84  */
85  for (frames = 1; frames < len && (buf[frames] & 0x80); frames++) ;
86 
87  if (1 + frames >= len) {
88  /* We hit the end of the packet while counting frames. */
89  av_log(ctx, AV_LOG_ERROR, "No speech data found\n");
90  return AVERROR_INVALIDDATA;
91  }
92 
93  speech_data = buf + 1 + frames;
94 
95  /* Everything except the codec mode request byte should be output. */
96  if (av_new_packet(pkt, len - 1)) {
97  av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
98  return AVERROR(ENOMEM);
99  }
100  pkt->stream_index = st->index;
101  ptr = pkt->data;
102 
103  for (i = 0; i < frames; i++) {
104  uint8_t toc = buf[1 + i];
105  int frame_size = frame_sizes[(toc >> 3) & 0x0f];
106 
107  if (speech_data + frame_size > buf + len) {
108  /* Too little speech data */
109  av_log(ctx, AV_LOG_WARNING, "Too little speech data in the RTP packet\n");
110  /* Set the unwritten part of the packet to zero. */
111  memset(ptr, 0, pkt->data + pkt->size - ptr);
112  pkt->size = ptr - pkt->data;
113  return 0;
114  }
115 
116  /* Extract the AMR frame mode from the TOC byte */
117  *ptr++ = toc & 0x7C;
118 
119  /* Copy the speech data */
120  memcpy(ptr, speech_data, frame_size);
121  speech_data += frame_size;
122  ptr += frame_size;
123  }
124 
125  if (speech_data < buf + len) {
126  av_log(ctx, AV_LOG_WARNING, "Too much speech data in the RTP packet?\n");
127  /* Set the unwritten part of the packet to zero. */
128  memset(ptr, 0, pkt->data + pkt->size - ptr);
129  pkt->size = ptr - pkt->data;
130  }
131 
132  return 0;
133 }
134 
136  AVStream *stream, PayloadContext *data,
137  const char *attr, const char *value)
138 {
139  /* Some AMR SDP configurations contain "octet-align", without
140  * the trailing =1. Therefore, if the value is empty,
141  * interpret it as "1".
142  */
143  if (!strcmp(value, "")) {
144  av_log(s, AV_LOG_WARNING, "AMR fmtp attribute %s had "
145  "nonstandard empty value\n", attr);
146  value = "1";
147  }
148  if (!strcmp(attr, "octet-align"))
149  data->octet_align = atoi(value);
150  else if (!strcmp(attr, "crc"))
151  data->crc = atoi(value);
152  else if (!strcmp(attr, "interleaving"))
153  data->interleaving = atoi(value);
154  else if (!strcmp(attr, "channels"))
155  data->channels = atoi(value);
156  return 0;
157 }
158 
159 static int amr_parse_sdp_line(AVFormatContext *s, int st_index,
160  PayloadContext *data, const char *line)
161 {
162  const char *p;
163  int ret;
164 
165  if (st_index < 0)
166  return 0;
167 
168  /* Parse an fmtp line this one:
169  * a=fmtp:97 octet-align=1; interleaving=0
170  * That is, a normal fmtp: line followed by semicolon & space
171  * separated key/value pairs.
172  */
173  if (av_strstart(line, "fmtp:", &p)) {
174  ret = ff_parse_fmtp(s, s->streams[st_index], data, p, amr_parse_fmtp);
175  if (!data->octet_align || data->crc ||
176  data->interleaving || data->channels != 1) {
177  av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n");
178  return -1;
179  }
180  return ret;
181  }
182  return 0;
183 }
184 
186  .enc_name = "AMR",
187  .codec_type = AVMEDIA_TYPE_AUDIO,
188  .codec_id = AV_CODEC_ID_AMR_NB,
189  .priv_data_size = sizeof(PayloadContext),
190  .init = amr_init,
191  .parse_sdp_a_line = amr_parse_sdp_line,
193 };
194 
196  .enc_name = "AMR-WB",
197  .codec_type = AVMEDIA_TYPE_AUDIO,
198  .codec_id = AV_CODEC_ID_AMR_WB,
199  .priv_data_size = sizeof(PayloadContext),
200  .init = amr_init,
201  .parse_sdp_a_line = amr_parse_sdp_line,
203 };
AVPacket pkt
Definition: rtpdec_qt.c:37
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
const RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler
Definition: rtpdec_amr.c:185
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
static int amr_parse_sdp_line(AVFormatContext *s, int st_index, PayloadContext *data, const char *line)
Definition: rtpdec_amr.c:159
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
static int amr_parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *attr, const char *value)
Definition: rtpdec_amr.c:135
RTP/JPEG specific private data.
Definition: rdt.c:83
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3960
int index
stream index in AVFormatContext
Definition: avformat.h:882
int size
Definition: avcodec.h:1481
if it could not because there are no more frames
Format I/O context.
Definition: avformat.h:1358
static const uint8_t frame_sizes[]
Definition: rtpdec_qcelp.c:24
uint8_t
#define av_cold
Definition: attributes.h:82
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:108
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
static int amr_handle_packet(AVFormatContext *ctx, PayloadContext *data, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags)
Definition: rtpdec_amr.c:47
uint8_t * data
Definition: avcodec.h:1480
uint64_t channel_layout
Audio only.
Definition: avcodec.h:4062
#define av_log(a,...)
static const uint8_t frame_sizes_nb[16]
Definition: rtpdec_amr.c:27
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:86
uint32_t timestamp
current frame timestamp
Definition: rtpdec_ac3.c:31
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
const RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler
Definition: rtpdec_amr.c:195
Definition: graph2dot.c:48
unsigned int frame_size
audio channel layout utility functions
AVFormatContext * ctx
Definition: movenc.c:48
#define s(width, name)
Definition: cbs_vp9.c:257
Stream structure.
Definition: avformat.h:881
static const uint8_t frame_sizes_wb[16]
Definition: rtpdec_amr.c:30
uint8_t * buf
the temporary storage buffer
Definition: rtpdec_asf.c:183
int ff_parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *p, int(*parse_fmtp)(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *attr, const char *value))
Definition: rtpdec.c:889
const char * enc_name
Definition: rtpdec.h:116
#define flags(name, subs,...)
Definition: cbs_av1.c:561
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
Main libavformat public API header.
static int parse_packet(AVFormatContext *s, AVPacket *pkt, int stream_index)
Parse a packet, add all split parts to parse_queue.
Definition: utils.c:1437
int channels
Audio only.
Definition: avcodec.h:4066
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int stream_index
Definition: avcodec.h:1482
static av_cold int amr_init(AVFormatContext *s, int st_index, PayloadContext *data)
Definition: rtpdec_amr.c:41
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1457