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rtpdec_h264.c
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1 /*
2  * RTP H264 Protocol (RFC3984)
3  * Copyright (c) 2006 Ryan Martell
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 /**
23  * @file
24  * @brief H.264 / RTP Code (RFC3984)
25  * @author Ryan Martell <rdm4@martellventures.com>
26  *
27  * @note Notes:
28  * Notes:
29  * This currently supports packetization mode:
30  * Single Nal Unit Mode (0), or
31  * Non-Interleaved Mode (1). It currently does not support
32  * Interleaved Mode (2). (This requires implementing STAP-B, MTAP16, MTAP24,
33  * FU-B packet types)
34  */
35 
36 #include "libavutil/base64.h"
37 #include "libavutil/avstring.h"
38 #include "libavcodec/get_bits.h"
39 #include "avformat.h"
40 
41 #include "network.h"
42 #include <assert.h>
43 
44 #include "rtpdec.h"
45 #include "rtpdec_formats.h"
46 
47 struct PayloadContext {
48  // sdp setup parameters
53 #ifdef DEBUG
54  int packet_types_received[32];
55 #endif
56 };
57 
58 #ifdef DEBUG
59 #define COUNT_NAL_TYPE(data, nal) data->packet_types_received[(nal) & 0x1f]++
60 #else
61 #define COUNT_NAL_TYPE(data, nal) do { } while (0)
62 #endif
63 
64 static const uint8_t start_sequence[] = { 0, 0, 0, 1 };
65 
67  PayloadContext *h264_data,
68  char *attr, char *value)
69 {
70  AVCodecContext *codec = stream->codec;
71  assert(codec->codec_id == AV_CODEC_ID_H264);
72  assert(h264_data != NULL);
73 
74  if (!strcmp(attr, "packetization-mode")) {
75  av_log(codec, AV_LOG_DEBUG, "RTP Packetization Mode: %d\n", atoi(value));
76  h264_data->packetization_mode = atoi(value);
77  /*
78  * Packetization Mode:
79  * 0 or not present: Single NAL mode (Only nals from 1-23 are allowed)
80  * 1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.
81  * 2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A),
82  * and 29 (FU-B) are allowed.
83  */
84  if (h264_data->packetization_mode > 1)
85  av_log(codec, AV_LOG_ERROR,
86  "Interleaved RTP mode is not supported yet.\n");
87  } else if (!strcmp(attr, "profile-level-id")) {
88  if (strlen(value) == 6) {
89  char buffer[3];
90  // 6 characters=3 bytes, in hex.
91  uint8_t profile_idc;
92  uint8_t profile_iop;
93  uint8_t level_idc;
94 
95  buffer[0] = value[0];
96  buffer[1] = value[1];
97  buffer[2] = '\0';
98  profile_idc = strtol(buffer, NULL, 16);
99  buffer[0] = value[2];
100  buffer[1] = value[3];
101  profile_iop = strtol(buffer, NULL, 16);
102  buffer[0] = value[4];
103  buffer[1] = value[5];
104  level_idc = strtol(buffer, NULL, 16);
105 
106  av_log(codec, AV_LOG_DEBUG,
107  "RTP Profile IDC: %x Profile IOP: %x Level: %x\n",
108  profile_idc, profile_iop, level_idc);
109  h264_data->profile_idc = profile_idc;
110  h264_data->profile_iop = profile_iop;
111  h264_data->level_idc = level_idc;
112  }
113  } else if (!strcmp(attr, "sprop-parameter-sets")) {
114  codec->extradata_size = 0;
115  av_freep(&codec->extradata);
116 
117  while (*value) {
118  char base64packet[1024];
119  uint8_t decoded_packet[1024];
120  int packet_size;
121  char *dst = base64packet;
122 
123  while (*value && *value != ','
124  && (dst - base64packet) < sizeof(base64packet) - 1) {
125  *dst++ = *value++;
126  }
127  *dst++ = '\0';
128 
129  if (*value == ',')
130  value++;
131 
132  packet_size = av_base64_decode(decoded_packet, base64packet,
133  sizeof(decoded_packet));
134  if (packet_size > 0) {
135  uint8_t *dest = av_malloc(packet_size + sizeof(start_sequence) +
136  codec->extradata_size +
138  if (!dest) {
139  av_log(codec, AV_LOG_ERROR,
140  "Unable to allocate memory for extradata!\n");
141  return AVERROR(ENOMEM);
142  }
143  if (codec->extradata_size) {
144  memcpy(dest, codec->extradata, codec->extradata_size);
145  av_free(codec->extradata);
146  }
147 
148  memcpy(dest + codec->extradata_size, start_sequence,
149  sizeof(start_sequence));
150  memcpy(dest + codec->extradata_size + sizeof(start_sequence),
151  decoded_packet, packet_size);
152  memset(dest + codec->extradata_size + sizeof(start_sequence) +
153  packet_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
154 
155  codec->extradata = dest;
156  codec->extradata_size += sizeof(start_sequence) + packet_size;
157  }
158  }
159  av_log(codec, AV_LOG_DEBUG, "Extradata set to %p (size: %d)!\n",
160  codec->extradata, codec->extradata_size);
161  }
162  return 0;
163 }
164 
165 // return 0 on packet, no more left, 1 on packet, 1 on partial packet
167  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
168  const uint8_t *buf, int len, uint16_t seq,
169  int flags)
170 {
171  uint8_t nal;
172  uint8_t type;
173  int result = 0;
174 
175  if (!len) {
176  av_log(ctx, AV_LOG_ERROR, "Empty H264 RTP packet\n");
177  return AVERROR_INVALIDDATA;
178  }
179  nal = buf[0];
180  type = nal & 0x1f;
181 
182  assert(data);
183  assert(buf);
184 
185  /* Simplify the case (these are all the nal types used internally by
186  * the h264 codec). */
187  if (type >= 1 && type <= 23)
188  type = 1;
189  switch (type) {
190  case 0: // undefined, but pass them through
191  case 1:
192  av_new_packet(pkt, len + sizeof(start_sequence));
193  memcpy(pkt->data, start_sequence, sizeof(start_sequence));
194  memcpy(pkt->data + sizeof(start_sequence), buf, len);
195  COUNT_NAL_TYPE(data, nal);
196  break;
197 
198  case 24: // STAP-A (one packet, multiple nals)
199  // consume the STAP-A NAL
200  buf++;
201  len--;
202  // first we are going to figure out the total size
203  {
204  int pass = 0;
205  int total_length = 0;
206  uint8_t *dst = NULL;
207 
208  for (pass = 0; pass < 2; pass++) {
209  const uint8_t *src = buf;
210  int src_len = len;
211 
212  while (src_len > 2) {
213  uint16_t nal_size = AV_RB16(src);
214 
215  // consume the length of the aggregate
216  src += 2;
217  src_len -= 2;
218 
219  if (nal_size <= src_len) {
220  if (pass == 0) {
221  // counting
222  total_length += sizeof(start_sequence) + nal_size;
223  } else {
224  // copying
225  assert(dst);
226  memcpy(dst, start_sequence, sizeof(start_sequence));
227  dst += sizeof(start_sequence);
228  memcpy(dst, src, nal_size);
229  COUNT_NAL_TYPE(data, *src);
230  dst += nal_size;
231  }
232  } else {
233  av_log(ctx, AV_LOG_ERROR,
234  "nal size exceeds length: %d %d\n", nal_size, src_len);
235  }
236 
237  // eat what we handled
238  src += nal_size;
239  src_len -= nal_size;
240 
241  if (src_len < 0)
242  av_log(ctx, AV_LOG_ERROR,
243  "Consumed more bytes than we got! (%d)\n", src_len);
244  }
245 
246  if (pass == 0) {
247  /* now we know the total size of the packet (with the
248  * start sequences added) */
249  av_new_packet(pkt, total_length);
250  dst = pkt->data;
251  } else {
252  assert(dst - pkt->data == total_length);
253  }
254  }
255  }
256  break;
257 
258  case 25: // STAP-B
259  case 26: // MTAP-16
260  case 27: // MTAP-24
261  case 29: // FU-B
262  av_log(ctx, AV_LOG_ERROR,
263  "Unhandled type (%d) (See RFC for implementation details\n",
264  type);
265  result = AVERROR(ENOSYS);
266  break;
267 
268  case 28: // FU-A (fragmented nal)
269  buf++;
270  len--; // skip the fu_indicator
271  if (len > 1) {
272  // these are the same as above, we just redo them here for clarity
273  uint8_t fu_indicator = nal;
274  uint8_t fu_header = *buf;
275  uint8_t start_bit = fu_header >> 7;
276  uint8_t av_unused end_bit = (fu_header & 0x40) >> 6;
277  uint8_t nal_type = fu_header & 0x1f;
278  uint8_t reconstructed_nal;
279 
280  // Reconstruct this packet's true nal; only the data follows.
281  /* The original nal forbidden bit and NRI are stored in this
282  * packet's nal. */
283  reconstructed_nal = fu_indicator & 0xe0;
284  reconstructed_nal |= nal_type;
285 
286  // skip the fu_header
287  buf++;
288  len--;
289 
290  if (start_bit)
291  COUNT_NAL_TYPE(data, nal_type);
292  if (start_bit) {
293  /* copy in the start sequence, and the reconstructed nal */
294  av_new_packet(pkt, sizeof(start_sequence) + sizeof(nal) + len);
295  memcpy(pkt->data, start_sequence, sizeof(start_sequence));
296  pkt->data[sizeof(start_sequence)] = reconstructed_nal;
297  memcpy(pkt->data + sizeof(start_sequence) + sizeof(nal), buf, len);
298  } else {
299  av_new_packet(pkt, len);
300  memcpy(pkt->data, buf, len);
301  }
302  } else {
303  av_log(ctx, AV_LOG_ERROR, "Too short data for FU-A H264 RTP packet\n");
304  result = AVERROR_INVALIDDATA;
305  }
306  break;
307 
308  case 30: // undefined
309  case 31: // undefined
310  default:
311  av_log(ctx, AV_LOG_ERROR, "Undefined type (%d)\n", type);
312  result = AVERROR_INVALIDDATA;
313  break;
314  }
315 
316  pkt->stream_index = st->index;
317 
318  return result;
319 }
320 
322 {
324 }
325 
327 {
328 #ifdef DEBUG
329  int ii;
330 
331  for (ii = 0; ii < 32; ii++) {
332  if (data->packet_types_received[ii])
333  av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",
334  data->packet_types_received[ii], ii);
335  }
336 #endif
337 
338  av_free(data);
339 }
340 
341 static int h264_init(AVFormatContext *s, int st_index, PayloadContext *data)
342 {
343  if (st_index < 0)
344  return 0;
345  s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
346  return 0;
347 }
348 
349 static int parse_h264_sdp_line(AVFormatContext *s, int st_index,
350  PayloadContext *h264_data, const char *line)
351 {
352  AVStream *stream;
353  AVCodecContext *codec;
354  const char *p = line;
355 
356  if (st_index < 0)
357  return 0;
358 
359  stream = s->streams[st_index];
360  codec = stream->codec;
361 
362  if (av_strstart(p, "framesize:", &p)) {
363  char buf1[50];
364  char *dst = buf1;
365 
366  // remove the protocol identifier
367  while (*p && *p == ' ')
368  p++; // strip spaces.
369  while (*p && *p != ' ')
370  p++; // eat protocol identifier
371  while (*p && *p == ' ')
372  p++; // strip trailing spaces.
373  while (*p && *p != '-' && (dst - buf1) < sizeof(buf1) - 1)
374  *dst++ = *p++;
375  *dst = '\0';
376 
377  // a='framesize:96 320-240'
378  // set our parameters
379  codec->width = atoi(buf1);
380  codec->height = atoi(p + 1); // skip the -
381  } else if (av_strstart(p, "fmtp:", &p)) {
382  return ff_parse_fmtp(stream, h264_data, p, sdp_parse_fmtp_config_h264);
383  } else if (av_strstart(p, "cliprect:", &p)) {
384  // could use this if we wanted.
385  }
386 
387  return 0;
388 }
389 
391  .enc_name = "H264",
392  .codec_type = AVMEDIA_TYPE_VIDEO,
393  .codec_id = AV_CODEC_ID_H264,
394  .init = h264_init,
395  .parse_sdp_a_line = parse_h264_sdp_line,
396  .alloc = h264_new_context,
397  .free = h264_free_context,
398  .parse_packet = h264_handle_packet
399 };