Libav
rtpdec_latm.c
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1 /*
2  * RTP Depacketization of MP4A-LATM, RFC 3016
3  * Copyright (c) 2010 Martin Storsjo
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 #include "rtpdec_formats.h"
23 #include "internal.h"
24 #include "libavutil/avstring.h"
25 #include "libavcodec/get_bits.h"
26 
27 struct PayloadContext {
29  uint8_t *buf;
30  int pos, len;
31  uint32_t timestamp;
32 };
33 
35 {
36  return av_mallocz(sizeof(PayloadContext));
37 }
38 
40 {
41  if (!data)
42  return;
43  if (data->dyn_buf) {
44  uint8_t *p;
45  avio_close_dyn_buf(data->dyn_buf, &p);
46  av_free(p);
47  }
48  av_free(data->buf);
49  av_free(data);
50 }
51 
53  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
54  const uint8_t *buf, int len, uint16_t seq,
55  int flags)
56 {
57  int ret, cur_len;
58 
59  if (buf) {
60  if (!data->dyn_buf || data->timestamp != *timestamp) {
61  av_freep(&data->buf);
62  if (data->dyn_buf)
63  avio_close_dyn_buf(data->dyn_buf, &data->buf);
64  data->dyn_buf = NULL;
65  av_freep(&data->buf);
66 
67  data->timestamp = *timestamp;
68  if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
69  return ret;
70  }
71  avio_write(data->dyn_buf, buf, len);
72 
73  if (!(flags & RTP_FLAG_MARKER))
74  return AVERROR(EAGAIN);
75  av_free(data->buf);
76  data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
77  data->dyn_buf = NULL;
78  data->pos = 0;
79  }
80 
81  if (!data->buf) {
82  av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
83  return AVERROR(EIO);
84  }
85 
86  cur_len = 0;
87  while (data->pos < data->len) {
88  uint8_t val = data->buf[data->pos++];
89  cur_len += val;
90  if (val != 0xff)
91  break;
92  }
93  if (data->pos + cur_len > data->len) {
94  av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
95  return AVERROR(EIO);
96  }
97 
98  if ((ret = av_new_packet(pkt, cur_len)) < 0)
99  return ret;
100  memcpy(pkt->data, data->buf + data->pos, cur_len);
101  data->pos += cur_len;
102  pkt->stream_index = st->index;
103  return data->pos < data->len;
104 }
105 
106 static int parse_fmtp_config(AVStream *st, char *value)
107 {
108  int len = ff_hex_to_data(NULL, value), i, ret = 0;
109  GetBitContext gb;
110  uint8_t *config;
111  int audio_mux_version, same_time_framing, num_programs, num_layers;
112 
113  /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
115  if (!config)
116  return AVERROR(ENOMEM);
117  ff_hex_to_data(config, value);
118  init_get_bits(&gb, config, len*8);
119  audio_mux_version = get_bits(&gb, 1);
120  same_time_framing = get_bits(&gb, 1);
121  skip_bits(&gb, 6); /* num_sub_frames */
122  num_programs = get_bits(&gb, 4);
123  num_layers = get_bits(&gb, 3);
124  if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
125  num_layers != 0) {
126  av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n",
127  audio_mux_version, same_time_framing,
128  num_programs, num_layers);
129  ret = AVERROR_PATCHWELCOME;
130  goto end;
131  }
132  av_freep(&st->codec->extradata);
133  st->codec->extradata_size = (get_bits_left(&gb) + 7)/8;
136  if (!st->codec->extradata) {
137  ret = AVERROR(ENOMEM);
138  goto end;
139  }
140  for (i = 0; i < st->codec->extradata_size; i++)
141  st->codec->extradata[i] = get_bits(&gb, 8);
142 
143 end:
144  av_free(config);
145  return ret;
146 }
147 
149  AVStream *stream, PayloadContext *data,
150  char *attr, char *value)
151 {
152  int res;
153 
154  if (!strcmp(attr, "config")) {
155  res = parse_fmtp_config(stream, value);
156  if (res < 0)
157  return res;
158  } else if (!strcmp(attr, "cpresent")) {
159  int cpresent = atoi(value);
160  if (cpresent != 0)
162  "RTP MP4A-LATM with in-band configuration");
163  }
164 
165  return 0;
166 }
167 
168 static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
169  PayloadContext *data, const char *line)
170 {
171  const char *p;
172 
173  if (st_index < 0)
174  return 0;
175 
176  if (av_strstart(line, "fmtp:", &p))
177  return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
178 
179  return 0;
180 }
181 
183  .enc_name = "MP4A-LATM",
184  .codec_type = AVMEDIA_TYPE_AUDIO,
185  .codec_id = AV_CODEC_ID_AAC,
186  .parse_sdp_a_line = latm_parse_sdp_line,
187  .alloc = latm_new_context,
188  .free = latm_free_context,
189  .parse_packet = latm_parse_packet
190 };
static int latm_parse_sdp_line(AVFormatContext *s, int st_index, PayloadContext *data, const char *line)
Definition: rtpdec_latm.c:168
Bytestream IO Context.
Definition: avio.h:68
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:977
int ff_parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *p, int(*parse_fmtp)(AVFormatContext *s, AVStream *stream, PayloadContext *data, char *attr, char *value))
Definition: rtpdec.c:829
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:240
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:129
RTP/JPEG specific private data.
Definition: rdt.c:83
int index
stream index in AVFormatContext
Definition: avformat.h:700
uint8_t * buf
the temporary storage buffer
Definition: rtpdec_asf.c:170
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:965
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:198
Format I/O context.
Definition: avformat.h:922
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
uint8_t
static int parse_fmtp_config(AVStream *st, char *value)
Definition: rtpdec_latm.c:106
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1164
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:990
const char data[16]
Definition: mxf.c:70
uint8_t * data
Definition: avcodec.h:973
static int flags
Definition: log.c:44
bitstream reader API header.
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:165
static int parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, char *attr, char *value)
Definition: rtpdec_latm.c:148
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:81
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:555
uint32_t timestamp
current frame timestamp
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:123
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:186
#define RTP_FLAG_MARKER
RTP marker bit was set for this packet.
Definition: rtpdec.h:93
#define AVERROR(e)
Definition: error.h:43
RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler
Definition: rtpdec_latm.c:182
Definition: graph2dot.c:49
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:169
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:718
#define FF_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:531
Stream structure.
Definition: avformat.h:699
#define AVERROR_PATCHWELCOME
Not yet implemented in Libav, patches welcome.
Definition: error.h:57
NULL
Definition: eval.c:55
static PayloadContext * latm_new_context(void)
Definition: rtpdec_latm.c:34
int extradata_size
Definition: avcodec.h:1165
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:263
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:375
const char enc_name[50]
Definition: rtpdec.h:116
int ff_hex_to_data(uint8_t *data, const char *p)
Parse a string of hexadecimal strings.
Definition: utils.c:2801
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:32
AVIOContext * dyn_buf
Definition: rtpdec_latm.c:28
static int latm_parse_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_latm.c:52
int len
int stream_index
Definition: avcodec.h:975
This structure stores compressed data.
Definition: avcodec.h:950
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:205
static void latm_free_context(PayloadContext *data)
Definition: rtpdec_latm.c:39