FFmpeg: libavformat/rtpdec_mpeg4.c Source File

FFmpeg
rtpdec_mpeg4.c
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1 /*
2  * Common code for the RTP depacketization of MPEG-4 formats.
3  * Copyright (c) 2010 Fabrice Bellard
4  * Romain Degez
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * @brief MPEG4 / RTP Code
26  * @author Fabrice Bellard
27  * @author Romain Degez
28  */
29 
30 #include "rtpdec_formats.h"
31 #include "internal.h"
32 #include "libavutil/attributes.h"
33 #include "libavutil/avstring.h"
34 #include "libavcodec/get_bits.h"
35 
36  #define MAX_AAC_HBR_FRAME_SIZE 8191
37 
38 /** Structure listing useful vars to parse RTP packet payload */
39 struct PayloadContext {
40   int sizelength;
41   int indexlength;
42   int indexdeltalength;
43   int profile_level_id;
44   int streamtype;
45   int objecttype;
46   char *mode;
47 
48  /** mpeg 4 AU headers */
49   struct AUHeaders {
50   int size;
51   int index;
52   int cts_flag;
53   int cts;
54   int dts_flag;
55   int dts;
56   int rap_flag;
57   int streamstate;
58  } *au_headers;
59   int au_headers_allocated;
60   int nb_au_headers;
61   int au_headers_length_bytes;
62   int cur_au_index;
63 
64   uint8_t buf[FFMAX(RTP_MAX_PACKET_LENGTH, MAX_AAC_HBR_FRAME_SIZE)];
65   int buf_pos, buf_size;
66  uint32_t timestamp;
67 };
68 
69  typedef struct AttrNameMap {
70   const char *str;
71   uint16_t type;
72   uint32_t offset;
73 } AttrNameMap;
74 
75 /* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
76  #define ATTR_NAME_TYPE_INT 0
77  #define ATTR_NAME_TYPE_STR 1
78  static const AttrNameMap attr_names[] = {
79  { "SizeLength", ATTR_NAME_TYPE_INT,
80  offsetof(PayloadContext, sizelength) },
81  { "IndexLength", ATTR_NAME_TYPE_INT,
82  offsetof(PayloadContext, indexlength) },
83  { "IndexDeltaLength", ATTR_NAME_TYPE_INT,
84  offsetof(PayloadContext, indexdeltalength) },
85  { "profile-level-id", ATTR_NAME_TYPE_INT,
86  offsetof(PayloadContext, profile_level_id) },
87  { "StreamType", ATTR_NAME_TYPE_INT,
88  offsetof(PayloadContext, streamtype) },
89  { "mode", ATTR_NAME_TYPE_STR,
90  offsetof(PayloadContext, mode) },
91  { NULL, -1, -1 },
92 };
93 
94  static void close_context(PayloadContext *data)
95 {
96  av_freep(&data->au_headers);
97  av_freep(&data->mode);
98 }
99 
100  static int parse_fmtp_config(AVCodecContext *codec, const char *value)
101 {
102  /* decode the hexa encoded parameter */
103  int len = ff_hex_to_data(NULL, value);
104  av_freep(&codec->extradata);
105  if (ff_alloc_extradata(codec, len))
106  return AVERROR(ENOMEM);
107  ff_hex_to_data(codec->extradata, value);
108  return 0;
109 }
110 
111  static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)
112 {
113  int au_headers_length, au_header_size, i;
114  GetBitContext getbitcontext;
115 
116  if (len < 2)
117  return AVERROR_INVALIDDATA;
118 
119  /* decode the first 2 bytes where the AUHeader sections are stored
120  length in bits */
121  au_headers_length = AV_RB16(buf);
122 
123  if (au_headers_length > RTP_MAX_PACKET_LENGTH)
124  return -1;
125 
126  data->au_headers_length_bytes = (au_headers_length + 7) / 8;
127 
128  /* skip AU headers length section (2 bytes) */
129  buf += 2;
130  len -= 2;
131 
132  if (len < data->au_headers_length_bytes)
133  return AVERROR_INVALIDDATA;
134 
135  init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);
136 
137  /* XXX: Wrong if optional additional sections are present (cts, dts etc...) */
138  au_header_size = data->sizelength + data->indexlength;
139  if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))
140  return -1;
141 
142  data->nb_au_headers = au_headers_length / au_header_size;
143  if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {
144  av_free(data->au_headers);
145  data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
146  if (!data->au_headers)
147  return AVERROR(ENOMEM);
148  data->au_headers_allocated = data->nb_au_headers;
149  }
150 
151  for (i = 0; i < data->nb_au_headers; ++i) {
152  data->au_headers[i].size = get_bits_long(&getbitcontext, data->sizelength);
153  data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);
154  }
155 
156  return 0;
157 }
158 
159 
160 /* Follows RFC 3640 */
161  static int aac_parse_packet(AVFormatContext *ctx, PayloadContext *data,
162  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
163  const uint8_t *buf, int len, uint16_t seq,
164  int flags)
165 {
166  int ret;
167 
168 
169  if (!buf) {
170  if (data->cur_au_index > data->nb_au_headers) {
171  av_log(ctx, AV_LOG_ERROR, "Invalid parser state\n");
172  return AVERROR_INVALIDDATA;
173  }
174  if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size) {
175  av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
176  return AVERROR_INVALIDDATA;
177  }
178  if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0) {
179  av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
180  return ret;
181  }
182  memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);
183  data->buf_pos += data->au_headers[data->cur_au_index].size;
184  pkt->stream_index = st->index;
185  data->cur_au_index++;
186 
187  if (data->cur_au_index == data->nb_au_headers) {
188  data->buf_pos = 0;
189  return 0;
190  }
191 
192  return 1;
193  }
194 
195  if (rtp_parse_mp4_au(data, buf, len)) {
196  av_log(ctx, AV_LOG_ERROR, "Error parsing AU headers\n");
197  return -1;
198  }
199 
200  buf += data->au_headers_length_bytes + 2;
201  len -= data->au_headers_length_bytes + 2;
202  if (data->nb_au_headers == 1 && len < data->au_headers[0].size) {
203  /* Packet is fragmented */
204 
205  if (!data->buf_pos) {
206  if (data->au_headers[0].size > MAX_AAC_HBR_FRAME_SIZE) {
207  av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
208  return AVERROR_INVALIDDATA;
209  }
210 
211  data->buf_size = data->au_headers[0].size;
212  data->timestamp = *timestamp;
213  }
214 
215  if (data->timestamp != *timestamp ||
216  data->au_headers[0].size != data->buf_size ||
217  data->buf_pos + len > MAX_AAC_HBR_FRAME_SIZE) {
218  data->buf_pos = 0;
219  data->buf_size = 0;
220  av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
221  return AVERROR_INVALIDDATA;
222  }
223 
224  memcpy(&data->buf[data->buf_pos], buf, len);
225  data->buf_pos += len;
226 
227  if (!(flags & RTP_FLAG_MARKER))
228  return AVERROR(EAGAIN);
229 
230  if (data->buf_pos != data->buf_size) {
231  data->buf_pos = 0;
232  av_log(ctx, AV_LOG_ERROR, "Missed some packets, discarding frame\n");
233  return AVERROR_INVALIDDATA;
234  }
235 
236  data->buf_pos = 0;
237  ret = av_new_packet(pkt, data->buf_size);
238  if (ret < 0) {
239  av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
240  return ret;
241  }
242  pkt->stream_index = st->index;
243 
244  memcpy(pkt->data, data->buf, data->buf_size);
245 
246  return 0;
247  }
248 
249  if (len < data->au_headers[0].size) {
250  av_log(ctx, AV_LOG_ERROR, "First AU larger than packet size\n");
251  return AVERROR_INVALIDDATA;
252  }
253  if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0) {
254  av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
255  return ret;
256  }
257  memcpy(pkt->data, buf, data->au_headers[0].size);
258  len -= data->au_headers[0].size;
259  buf += data->au_headers[0].size;
260  pkt->stream_index = st->index;
261 
262  if (len > 0 && data->nb_au_headers > 1) {
263  data->buf_size = FFMIN(len, sizeof(data->buf));
264  memcpy(data->buf, buf, data->buf_size);
265  data->cur_au_index = 1;
266  data->buf_pos = 0;
267  return 1;
268  }
269 
270  return 0;
271 }
272 
273  static int parse_fmtp(AVFormatContext *s,
274  AVStream *stream, PayloadContext *data,
275  const char *attr, const char *value)
276 {
277  AVCodecContext *codec = stream->codec;
278  int res, i;
279 
280  if (!strcmp(attr, "config")) {
281  res = parse_fmtp_config(codec, value);
282 
283  if (res < 0)
284  return res;
285  }
286 
287  if (codec->codec_id == AV_CODEC_ID_AAC) {
288  /* Looking for a known attribute */
289  for (i = 0; attr_names[i].str; ++i) {
290  if (!av_strcasecmp(attr, attr_names[i].str)) {
291  if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
292  *(int *)((char *)data+
293  attr_names[i].offset) = atoi(value);
294  } else if (attr_names[i].type == ATTR_NAME_TYPE_STR)
295  *(char **)((char *)data+
296  attr_names[i].offset) = av_strdup(value);
297  }
298  }
299  }
300  return 0;
301 }
302 
303  static int parse_sdp_line(AVFormatContext *s, int st_index,
304  PayloadContext *data, const char *line)
305 {
306  const char *p;
307 
308  if (st_index < 0)
309  return 0;
310 
311  if (av_strstart(line, "fmtp:", &p))
312  return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
313 
314  return 0;
315 }
316 
317  RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
318  .enc_name = "MP4V-ES",
319  .codec_type = AVMEDIA_TYPE_VIDEO,
320  .codec_id = AV_CODEC_ID_MPEG4,
321  .need_parsing = AVSTREAM_PARSE_FULL,
322  .priv_data_size = sizeof(PayloadContext),
323  .parse_sdp_a_line = parse_sdp_line,
324 };
325 
326  RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
327  .enc_name = "mpeg4-generic",
328  .codec_type = AVMEDIA_TYPE_AUDIO,
329  .codec_id = AV_CODEC_ID_AAC,
330  .priv_data_size = sizeof(PayloadContext),
331  .parse_sdp_a_line = parse_sdp_line,
332  .close = close_context,
333  .parse_packet = aac_parse_packet,
334 };
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