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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/attributes.h"
37 #include "libavutil/base64.h"
38 #include "libavutil/avstring.h"
39 #include "libavcodec/get_bits.h"
40 #include "avformat.h"
41 
42 #include "network.h"
43 #include <assert.h>
44 
45 #include "rtpdec.h"
46 #include "rtpdec_formats.h"
47 
48 struct PayloadContext {
49  // sdp setup parameters
54 #ifdef DEBUG
55  int packet_types_received[32];
56 #endif
57 };
58 
59 #ifdef DEBUG
60 #define COUNT_NAL_TYPE(data, nal) data->packet_types_received[(nal) & 0x1f]++
61 #else
62 #define COUNT_NAL_TYPE(data, nal) do { } while (0)
63 #endif
64 
65 static const uint8_t start_sequence[] = { 0, 0, 0, 1 };
66 
68  PayloadContext *h264_data,
69  char *attr, char *value)
70 {
71  AVCodecContext *codec = stream->codec;
72  assert(codec->codec_id == AV_CODEC_ID_H264);
73  assert(h264_data != NULL);
74 
75  if (!strcmp(attr, "packetization-mode")) {
76  av_log(codec, AV_LOG_DEBUG, "RTP Packetization Mode: %d\n", atoi(value));
77  h264_data->packetization_mode = atoi(value);
78  /*
79  * Packetization Mode:
80  * 0 or not present: Single NAL mode (Only nals from 1-23 are allowed)
81  * 1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.
82  * 2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A),
83  * and 29 (FU-B) are allowed.
84  */
85  if (h264_data->packetization_mode > 1)
86  av_log(codec, AV_LOG_ERROR,
87  "Interleaved RTP mode is not supported yet.\n");
88  } else if (!strcmp(attr, "profile-level-id")) {
89  if (strlen(value) == 6) {
90  char buffer[3];
91  // 6 characters=3 bytes, in hex.
92  uint8_t profile_idc;
93  uint8_t profile_iop;
94  uint8_t level_idc;
95 
96  buffer[0] = value[0];
97  buffer[1] = value[1];
98  buffer[2] = '\0';
99  profile_idc = strtol(buffer, NULL, 16);
100  buffer[0] = value[2];
101  buffer[1] = value[3];
102  profile_iop = strtol(buffer, NULL, 16);
103  buffer[0] = value[4];
104  buffer[1] = value[5];
105  level_idc = strtol(buffer, NULL, 16);
106 
107  av_log(codec, AV_LOG_DEBUG,
108  "RTP Profile IDC: %x Profile IOP: %x Level: %x\n",
109  profile_idc, profile_iop, level_idc);
110  h264_data->profile_idc = profile_idc;
111  h264_data->profile_iop = profile_iop;
112  h264_data->level_idc = level_idc;
113  }
114  } else if (!strcmp(attr, "sprop-parameter-sets")) {
115  codec->extradata_size = 0;
116  av_freep(&codec->extradata);
117 
118  while (*value) {
119  char base64packet[1024];
120  uint8_t decoded_packet[1024];
121  int packet_size;
122  char *dst = base64packet;
123 
124  while (*value && *value != ','
125  && (dst - base64packet) < sizeof(base64packet) - 1) {
126  *dst++ = *value++;
127  }
128  *dst++ = '\0';
129 
130  if (*value == ',')
131  value++;
132 
133  packet_size = av_base64_decode(decoded_packet, base64packet,
134  sizeof(decoded_packet));
135  if (packet_size > 0) {
136  uint8_t *dest = av_malloc(packet_size + sizeof(start_sequence) +
137  codec->extradata_size +
139  if (!dest) {
140  av_log(codec, AV_LOG_ERROR,
141  "Unable to allocate memory for extradata!\n");
142  return AVERROR(ENOMEM);
143  }
144  if (codec->extradata_size) {
145  memcpy(dest, codec->extradata, codec->extradata_size);
146  av_free(codec->extradata);
147  }
148 
149  memcpy(dest + codec->extradata_size, start_sequence,
150  sizeof(start_sequence));
151  memcpy(dest + codec->extradata_size + sizeof(start_sequence),
152  decoded_packet, packet_size);
153  memset(dest + codec->extradata_size + sizeof(start_sequence) +
154  packet_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
155 
156  codec->extradata = dest;
157  codec->extradata_size += sizeof(start_sequence) + packet_size;
158  }
159  }
160  av_log(codec, AV_LOG_DEBUG, "Extradata set to %p (size: %d)!\n",
161  codec->extradata, codec->extradata_size);
162  }
163  return 0;
164 }
165 
166 // return 0 on packet, no more left, 1 on packet, 1 on partial packet
168  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
169  const uint8_t *buf, int len, uint16_t seq,
170  int flags)
171 {
172  uint8_t nal;
173  uint8_t type;
174  int result = 0;
175 
176  if (!len) {
177  av_log(ctx, AV_LOG_ERROR, "Empty H264 RTP packet\n");
178  return AVERROR_INVALIDDATA;
179  }
180  nal = buf[0];
181  type = nal & 0x1f;
182 
183  assert(data);
184  assert(buf);
185 
186  /* Simplify the case (these are all the nal types used internally by
187  * the h264 codec). */
188  if (type >= 1 && type <= 23)
189  type = 1;
190  switch (type) {
191  case 0: // undefined, but pass them through
192  case 1:
193  av_new_packet(pkt, len + sizeof(start_sequence));
194  memcpy(pkt->data, start_sequence, sizeof(start_sequence));
195  memcpy(pkt->data + sizeof(start_sequence), buf, len);
196  COUNT_NAL_TYPE(data, nal);
197  break;
198 
199  case 24: // STAP-A (one packet, multiple nals)
200  // consume the STAP-A NAL
201  buf++;
202  len--;
203  // first we are going to figure out the total size
204  {
205  int pass = 0;
206  int total_length = 0;
207  uint8_t *dst = NULL;
208 
209  for (pass = 0; pass < 2; pass++) {
210  const uint8_t *src = buf;
211  int src_len = len;
212 
213  while (src_len > 2) {
214  uint16_t nal_size = AV_RB16(src);
215 
216  // consume the length of the aggregate
217  src += 2;
218  src_len -= 2;
219 
220  if (nal_size <= src_len) {
221  if (pass == 0) {
222  // counting
223  total_length += sizeof(start_sequence) + nal_size;
224  } else {
225  // copying
226  assert(dst);
227  memcpy(dst, start_sequence, sizeof(start_sequence));
228  dst += sizeof(start_sequence);
229  memcpy(dst, src, nal_size);
230  COUNT_NAL_TYPE(data, *src);
231  dst += nal_size;
232  }
233  } else {
234  av_log(ctx, AV_LOG_ERROR,
235  "nal size exceeds length: %d %d\n", nal_size, src_len);
236  }
237 
238  // eat what we handled
239  src += nal_size;
240  src_len -= nal_size;
241 
242  if (src_len < 0)
243  av_log(ctx, AV_LOG_ERROR,
244  "Consumed more bytes than we got! (%d)\n", src_len);
245  }
246 
247  if (pass == 0) {
248  /* now we know the total size of the packet (with the
249  * start sequences added) */
250  av_new_packet(pkt, total_length);
251  dst = pkt->data;
252  } else {
253  assert(dst - pkt->data == total_length);
254  }
255  }
256  }
257  break;
258 
259  case 25: // STAP-B
260  case 26: // MTAP-16
261  case 27: // MTAP-24
262  case 29: // FU-B
263  av_log(ctx, AV_LOG_ERROR,
264  "Unhandled type (%d) (See RFC for implementation details\n",
265  type);
266  result = AVERROR(ENOSYS);
267  break;
268 
269  case 28: // FU-A (fragmented nal)
270  buf++;
271  len--; // skip the fu_indicator
272  if (len > 1) {
273  // these are the same as above, we just redo them here for clarity
274  uint8_t fu_indicator = nal;
275  uint8_t fu_header = *buf;
276  uint8_t start_bit = fu_header >> 7;
277  uint8_t av_unused end_bit = (fu_header & 0x40) >> 6;
278  uint8_t nal_type = fu_header & 0x1f;
279  uint8_t reconstructed_nal;
280 
281  // Reconstruct this packet's true nal; only the data follows.
282  /* The original nal forbidden bit and NRI are stored in this
283  * packet's nal. */
284  reconstructed_nal = fu_indicator & 0xe0;
285  reconstructed_nal |= nal_type;
286 
287  // skip the fu_header
288  buf++;
289  len--;
290 
291  if (start_bit)
292  COUNT_NAL_TYPE(data, nal_type);
293  if (start_bit) {
294  /* copy in the start sequence, and the reconstructed nal */
295  av_new_packet(pkt, sizeof(start_sequence) + sizeof(nal) + len);
296  memcpy(pkt->data, start_sequence, sizeof(start_sequence));
297  pkt->data[sizeof(start_sequence)] = reconstructed_nal;
298  memcpy(pkt->data + sizeof(start_sequence) + sizeof(nal), buf, len);
299  } else {
300  av_new_packet(pkt, len);
301  memcpy(pkt->data, buf, len);
302  }
303  } else {
304  av_log(ctx, AV_LOG_ERROR, "Too short data for FU-A H264 RTP packet\n");
305  result = AVERROR_INVALIDDATA;
306  }
307  break;
308 
309  case 30: // undefined
310  case 31: // undefined
311  default:
312  av_log(ctx, AV_LOG_ERROR, "Undefined type (%d)\n", type);
313  result = AVERROR_INVALIDDATA;
314  break;
315  }
316 
317  pkt->stream_index = st->index;
318 
319  return result;
320 }
321 
323 {
325 }
326 
328 {
329 #ifdef DEBUG
330  int ii;
331 
332  for (ii = 0; ii < 32; ii++) {
333  if (data->packet_types_received[ii])
334  av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",
335  data->packet_types_received[ii], ii);
336  }
337 #endif
338 
339  av_free(data);
340 }
341 
342 static av_cold int h264_init(AVFormatContext *s, int st_index,
344 {
345  if (st_index < 0)
346  return 0;
347  s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
348  return 0;
349 }
350 
351 static int parse_h264_sdp_line(AVFormatContext *s, int st_index,
352  PayloadContext *h264_data, const char *line)
353 {
354  AVStream *stream;
355  AVCodecContext *codec;
356  const char *p = line;
357 
358  if (st_index < 0)
359  return 0;
360 
361  stream = s->streams[st_index];
362  codec = stream->codec;
363 
364  if (av_strstart(p, "framesize:", &p)) {
365  char buf1[50];
366  char *dst = buf1;
367 
368  // remove the protocol identifier
369  while (*p && *p == ' ')
370  p++; // strip spaces.
371  while (*p && *p != ' ')
372  p++; // eat protocol identifier
373  while (*p && *p == ' ')
374  p++; // strip trailing spaces.
375  while (*p && *p != '-' && (dst - buf1) < sizeof(buf1) - 1)
376  *dst++ = *p++;
377  *dst = '\0';
378 
379  // a='framesize:96 320-240'
380  // set our parameters
381  codec->width = atoi(buf1);
382  codec->height = atoi(p + 1); // skip the -
383  } else if (av_strstart(p, "fmtp:", &p)) {
384  return ff_parse_fmtp(stream, h264_data, p, sdp_parse_fmtp_config_h264);
385  } else if (av_strstart(p, "cliprect:", &p)) {
386  // could use this if we wanted.
387  }
388 
389  return 0;
390 }
391 
393  .enc_name = "H264",
394  .codec_type = AVMEDIA_TYPE_VIDEO,
395  .codec_id = AV_CODEC_ID_H264,
396  .init = h264_init,
397  .parse_sdp_a_line = parse_h264_sdp_line,
398  .alloc = h264_new_context,
399  .free = h264_free_context,
400  .parse_packet = h264_handle_packet
401 };