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rtpdec_xiph.c
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1 /*
2  * Xiph RTP Protocols
3  * Copyright (c) 2009 Colin McQuillian
4  * Copyright (c) 2010 Josh Allmann
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 Xiph / RTP Code
26  * @author Colin McQuillan <m.niloc@gmail.com>
27  * @author Josh Allmann <joshua.allmann@gmail.com>
28  */
29 
30 #include "libavutil/attributes.h"
31 #include "libavutil/avassert.h"
32 #include "libavutil/avstring.h"
33 #include "libavutil/base64.h"
34 #include "libavcodec/bytestream.h"
35 
36 #include "rtpdec.h"
37 #include "rtpdec_formats.h"
38 
39 /**
40  * RTP/Xiph specific private data.
41  */
42 struct PayloadContext {
43  unsigned ident; ///< 24-bit stream configuration identifier
44  uint32_t timestamp;
45  AVIOContext* fragment; ///< buffer for split payloads
49 };
50 
52 {
53  return av_mallocz(sizeof(PayloadContext));
54 }
55 
57 {
58  if (data->fragment) {
59  uint8_t* p;
60  avio_close_dyn_buf(data->fragment, &p);
61  av_free(p);
62  data->fragment = NULL;
63  }
64 }
65 
67 {
69  av_free(data->split_buf);
70  av_free(data);
71 }
72 
73 static av_cold int xiph_vorbis_init(AVFormatContext *ctx, int st_index,
75 {
76  if (st_index < 0)
77  return 0;
79  return 0;
80 }
81 
82 
84  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
85  const uint8_t *buf, int len, uint16_t seq,
86  int flags)
87 {
88 
89  int ident, fragmented, tdt, num_pkts, pkt_len;
90 
91  if (!buf) {
92  if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||
93  data->split_pkts <= 0) {
94  av_log(ctx, AV_LOG_ERROR, "No more data to return\n");
95  return AVERROR_INVALIDDATA;
96  }
97  pkt_len = AV_RB16(data->split_buf + data->split_pos);
98  data->split_pos += 2;
99  if (data->split_pos + pkt_len > data->split_buf_len) {
100  av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");
101  return AVERROR_INVALIDDATA;
102  }
103  if (av_new_packet(pkt, pkt_len)) {
104  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
105  return AVERROR(ENOMEM);
106  }
107  pkt->stream_index = st->index;
108  memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);
109  data->split_pos += pkt_len;
110  data->split_pkts--;
111  return data->split_pkts > 0;
112  }
113 
114  if (len < 6) {
115  av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
116  return AVERROR_INVALIDDATA;
117  }
118 
119  // read xiph rtp headers
120  ident = AV_RB24(buf);
121  fragmented = buf[3] >> 6;
122  tdt = (buf[3] >> 4) & 3;
123  num_pkts = buf[3] & 0xf;
124  pkt_len = AV_RB16(buf + 4);
125 
126  if (pkt_len > len - 6) {
127  av_log(ctx, AV_LOG_ERROR,
128  "Invalid packet length %d in %d byte packet\n", pkt_len,
129  len);
130  return AVERROR_INVALIDDATA;
131  }
132 
133  if (ident != data->ident) {
134  av_log(ctx, AV_LOG_ERROR,
135  "Unimplemented Xiph SDP configuration change detected\n");
136  return AVERROR_PATCHWELCOME;
137  }
138 
139  if (tdt) {
140  av_log(ctx, AV_LOG_ERROR,
141  "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
142  fragmented, tdt, num_pkts);
143  return AVERROR_PATCHWELCOME;
144  }
145 
146  buf += 6; // move past header bits
147  len -= 6;
148 
149  if (fragmented == 0) {
150  if (av_new_packet(pkt, pkt_len)) {
151  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
152  return AVERROR(ENOMEM);
153  }
154  pkt->stream_index = st->index;
155  memcpy(pkt->data, buf, pkt_len);
156  buf += pkt_len;
157  len -= pkt_len;
158  num_pkts--;
159 
160  if (num_pkts > 0) {
161  if (len > data->split_buf_size || !data->split_buf) {
162  av_freep(&data->split_buf);
163  data->split_buf_size = 2 * len;
164  data->split_buf = av_malloc(data->split_buf_size);
165  if (!data->split_buf) {
166  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
167  av_free_packet(pkt);
168  return AVERROR(ENOMEM);
169  }
170  }
171  memcpy(data->split_buf, buf, len);
172  data->split_buf_len = len;
173  data->split_pos = 0;
174  data->split_pkts = num_pkts;
175  return 1;
176  }
177 
178  return 0;
179 
180  } else if (fragmented == 1) {
181  // start of xiph data fragment
182  int res;
183 
184  // end packet has been lost somewhere, so drop buffered data
186 
187  if((res = avio_open_dyn_buf(&data->fragment)) < 0)
188  return res;
189 
190  avio_write(data->fragment, buf, pkt_len);
191  data->timestamp = *timestamp;
192 
193  } else {
194  av_assert1(fragmented < 4);
195  if (data->timestamp != *timestamp) {
196  // skip if fragmented timestamp is incorrect;
197  // a start packet has been lost somewhere
199  av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
200  return AVERROR_INVALIDDATA;
201  }
202  if (!data->fragment) {
203  av_log(ctx, AV_LOG_WARNING,
204  "Received packet without a start fragment; dropping.\n");
205  return AVERROR(EAGAIN);
206  }
207 
208  // copy data to fragment buffer
209  avio_write(data->fragment, buf, pkt_len);
210 
211  if (fragmented == 3) {
212  // end of xiph data packet
213  int ret = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
214  if (ret < 0) {
215  av_log(ctx, AV_LOG_ERROR,
216  "Error occurred when getting fragment buffer.");
217  return ret;
218  }
219 
220  return 0;
221  }
222  }
223 
224  return AVERROR(EAGAIN);
225 }
226 
227 /**
228  * Length encoding described in RFC5215 section 3.1.1.
229  */
230 static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
231 {
232  int n = 0;
233  for (; *buf < buf_end; ++*buf) {
234  n <<= 7;
235  n += **buf & 0x7f;
236  if (!(**buf & 0x80)) {
237  ++*buf;
238  return n;
239  }
240  }
241  return 0;
242 }
243 
244 /**
245  * Based off parse_packed_headers in Vorbis RTP
246  */
247 static int
248 parse_packed_headers(const uint8_t * packed_headers,
249  const uint8_t * packed_headers_end,
250  AVCodecContext * codec, PayloadContext * xiph_data)
251 {
252 
253  unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
254  uint8_t *ptr;
255 
256  if (packed_headers_end - packed_headers < 9) {
257  av_log(codec, AV_LOG_ERROR,
258  "Invalid %td byte packed header.",
259  packed_headers_end - packed_headers);
260  return AVERROR_INVALIDDATA;
261  }
262 
263  num_packed = bytestream_get_be32(&packed_headers);
264  xiph_data->ident = bytestream_get_be24(&packed_headers);
265  length = bytestream_get_be16(&packed_headers);
266  num_headers = get_base128(&packed_headers, packed_headers_end);
267  length1 = get_base128(&packed_headers, packed_headers_end);
268  length2 = get_base128(&packed_headers, packed_headers_end);
269 
270  if (num_packed != 1 || num_headers > 3) {
271  av_log(codec, AV_LOG_ERROR,
272  "Unimplemented number of headers: %d packed headers, %d headers\n",
273  num_packed, num_headers);
274  return AVERROR_PATCHWELCOME;
275  }
276 
277  if (packed_headers_end - packed_headers != length ||
278  length1 > length || length2 > length - length1) {
279  av_log(codec, AV_LOG_ERROR,
280  "Bad packed header lengths (%d,%d,%td,%d)\n", length1,
281  length2, packed_headers_end - packed_headers, length);
282  return AVERROR_INVALIDDATA;
283  }
284 
285  /* allocate extra space:
286  * -- length/255 +2 for xiphlacing
287  * -- one for the '2' marker
288  * -- FF_INPUT_BUFFER_PADDING_SIZE required */
289  extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
290 
291  ptr = codec->extradata = av_malloc(extradata_alloc);
292  if (!ptr) {
293  av_log(codec, AV_LOG_ERROR, "Out of memory\n");
294  return AVERROR(ENOMEM);
295  }
296  *ptr++ = 2;
297  ptr += av_xiphlacing(ptr, length1);
298  ptr += av_xiphlacing(ptr, length2);
299  memcpy(ptr, packed_headers, length);
300  ptr += length;
301  codec->extradata_size = ptr - codec->extradata;
302  // clear out remaining parts of the buffer
303  memset(ptr, 0, extradata_alloc - codec->extradata_size);
304 
305  return 0;
306 }
307 
308 static int xiph_parse_fmtp_pair(AVStream* stream,
309  PayloadContext *xiph_data,
310  char *attr, char *value)
311 {
312  AVCodecContext *codec = stream->codec;
313  int result = 0;
314 
315  if (!strcmp(attr, "sampling")) {
316  if (!strcmp(value, "YCbCr-4:2:0")) {
317  codec->pix_fmt = AV_PIX_FMT_YUV420P;
318  } else if (!strcmp(value, "YCbCr-4:4:2")) {
319  codec->pix_fmt = AV_PIX_FMT_YUV422P;
320  } else if (!strcmp(value, "YCbCr-4:4:4")) {
321  codec->pix_fmt = AV_PIX_FMT_YUV444P;
322  } else {
323  av_log(codec, AV_LOG_ERROR,
324  "Unsupported pixel format %s\n", attr);
325  return AVERROR_INVALIDDATA;
326  }
327  } else if (!strcmp(attr, "width")) {
328  /* This is an integer between 1 and 1048561
329  * and MUST be in multiples of 16. */
330  codec->width = atoi(value);
331  return 0;
332  } else if (!strcmp(attr, "height")) {
333  /* This is an integer between 1 and 1048561
334  * and MUST be in multiples of 16. */
335  codec->height = atoi(value);
336  return 0;
337  } else if (!strcmp(attr, "delivery-method")) {
338  /* Possible values are: inline, in_band, out_band/specific_name. */
339  return AVERROR_PATCHWELCOME;
340  } else if (!strcmp(attr, "configuration-uri")) {
341  /* NOTE: configuration-uri is supported only under 2 conditions:
342  *--after the delivery-method tag
343  * --with a delivery-method value of out_band */
344  return AVERROR_PATCHWELCOME;
345  } else if (!strcmp(attr, "configuration")) {
346  /* NOTE: configuration is supported only AFTER the delivery-method tag
347  * The configuration value is a base64 encoded packed header */
348  uint8_t *decoded_packet = NULL;
349  int packet_size;
350  size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
351 
352  if (decoded_alloc <= INT_MAX) {
353  decoded_packet = av_malloc(decoded_alloc);
354  if (decoded_packet) {
355  packet_size =
356  av_base64_decode(decoded_packet, value, decoded_alloc);
357 
358  result = parse_packed_headers
359  (decoded_packet, decoded_packet + packet_size, codec,
360  xiph_data);
361  } else {
362  av_log(codec, AV_LOG_ERROR,
363  "Out of memory while decoding SDP configuration.\n");
364  result = AVERROR(ENOMEM);
365  }
366  } else {
367  av_log(codec, AV_LOG_ERROR, "Packet too large\n");
368  result = AVERROR_INVALIDDATA;
369  }
370  av_free(decoded_packet);
371  }
372  return result;
373 }
374 
375 static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
376  PayloadContext *data, const char *line)
377 {
378  const char *p;
379 
380  if (st_index < 0)
381  return 0;
382 
383  if (av_strstart(line, "fmtp:", &p)) {
384  return ff_parse_fmtp(s->streams[st_index], data, p,
386  }
387 
388  return 0;
389 }
390 
392  .enc_name = "theora",
393  .codec_type = AVMEDIA_TYPE_VIDEO,
394  .codec_id = AV_CODEC_ID_THEORA,
395  .parse_sdp_a_line = xiph_parse_sdp_line,
396  .alloc = xiph_new_context,
397  .free = xiph_free_context,
398  .parse_packet = xiph_handle_packet
399 };
400 
402  .enc_name = "vorbis",
403  .codec_type = AVMEDIA_TYPE_AUDIO,
404  .codec_id = AV_CODEC_ID_VORBIS,
405  .init = xiph_vorbis_init,
406  .parse_sdp_a_line = xiph_parse_sdp_line,
407  .alloc = xiph_new_context,
408  .free = xiph_free_context,
409  .parse_packet = xiph_handle_packet
410 };