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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 "avio_internal.h"
37 #include "internal.h"
38 #include "rtpdec.h"
39 #include "rtpdec_formats.h"
40 
41 /**
42  * RTP/Xiph specific private data.
43  */
44 struct PayloadContext {
45  unsigned ident; ///< 24-bit stream configuration identifier
46  uint32_t timestamp;
47  AVIOContext* fragment; ///< buffer for split payloads
50  int split_pkts;
51 };
52 
54 {
56  av_freep(&data->split_buf);
57 }
58 
59 
61  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
62  const uint8_t *buf, int len, uint16_t seq,
63  int flags)
64 {
65 
66  int ident, fragmented, tdt, num_pkts, pkt_len;
67 
68  if (!buf) {
69  if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||
70  data->split_pkts <= 0) {
71  av_log(ctx, AV_LOG_ERROR, "No more data to return\n");
72  return AVERROR_INVALIDDATA;
73  }
74  pkt_len = AV_RB16(data->split_buf + data->split_pos);
75  data->split_pos += 2;
76  if (pkt_len > data->split_buf_len - data->split_pos) {
77  av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");
78  return AVERROR_INVALIDDATA;
79  }
80  if (av_new_packet(pkt, pkt_len)) {
81  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
82  return AVERROR(ENOMEM);
83  }
84  pkt->stream_index = st->index;
85  memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);
86  data->split_pos += pkt_len;
87  data->split_pkts--;
88  return data->split_pkts > 0;
89  }
90 
91  if (len < 6 || len > INT_MAX/2) {
92  av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
93  return AVERROR_INVALIDDATA;
94  }
95 
96  // read xiph rtp headers
97  ident = AV_RB24(buf);
98  fragmented = buf[3] >> 6;
99  tdt = (buf[3] >> 4) & 3;
100  num_pkts = buf[3] & 0xf;
101  pkt_len = AV_RB16(buf + 4);
102 
103  if (pkt_len > len - 6) {
104  av_log(ctx, AV_LOG_ERROR,
105  "Invalid packet length %d in %d byte packet\n", pkt_len,
106  len);
107  return AVERROR_INVALIDDATA;
108  }
109 
110  if (ident != data->ident) {
111  av_log(ctx, AV_LOG_ERROR,
112  "Unimplemented Xiph SDP configuration change detected\n");
113  return AVERROR_PATCHWELCOME;
114  }
115 
116  if (tdt) {
117  av_log(ctx, AV_LOG_ERROR,
118  "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
119  fragmented, tdt, num_pkts);
120  return AVERROR_PATCHWELCOME;
121  }
122 
123  buf += 6; // move past header bits
124  len -= 6;
125 
126  if (fragmented == 0) {
127  if (av_new_packet(pkt, pkt_len)) {
128  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
129  return AVERROR(ENOMEM);
130  }
131  pkt->stream_index = st->index;
132  memcpy(pkt->data, buf, pkt_len);
133  buf += pkt_len;
134  len -= pkt_len;
135  num_pkts--;
136 
137  if (num_pkts > 0) {
138  if (len > data->split_buf_size || !data->split_buf) {
139  av_freep(&data->split_buf);
140  data->split_buf_size = 2 * len;
141  data->split_buf = av_malloc(data->split_buf_size);
142  if (!data->split_buf) {
143  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
144  av_free_packet(pkt);
145  return AVERROR(ENOMEM);
146  }
147  }
148  memcpy(data->split_buf, buf, len);
149  data->split_buf_len = len;
150  data->split_pos = 0;
151  data->split_pkts = num_pkts;
152  return 1;
153  }
154 
155  return 0;
156 
157  } else if (fragmented == 1) {
158  // start of xiph data fragment
159  int res;
160 
161  // end packet has been lost somewhere, so drop buffered data
162  ffio_free_dyn_buf(&data->fragment);
163 
164  if((res = avio_open_dyn_buf(&data->fragment)) < 0)
165  return res;
166 
167  avio_write(data->fragment, buf, pkt_len);
168  data->timestamp = *timestamp;
169 
170  } else {
171  av_assert1(fragmented < 4);
172  if (data->timestamp != *timestamp) {
173  // skip if fragmented timestamp is incorrect;
174  // a start packet has been lost somewhere
175  ffio_free_dyn_buf(&data->fragment);
176  av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
177  return AVERROR_INVALIDDATA;
178  }
179  if (!data->fragment) {
180  av_log(ctx, AV_LOG_WARNING,
181  "Received packet without a start fragment; dropping.\n");
182  return AVERROR(EAGAIN);
183  }
184 
185  // copy data to fragment buffer
186  avio_write(data->fragment, buf, pkt_len);
187 
188  if (fragmented == 3) {
189  // end of xiph data packet
190  int ret = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
191  if (ret < 0) {
192  av_log(ctx, AV_LOG_ERROR,
193  "Error occurred when getting fragment buffer.");
194  return ret;
195  }
196 
197  return 0;
198  }
199  }
200 
201  return AVERROR(EAGAIN);
202 }
203 
204 /**
205  * Length encoding described in RFC5215 section 3.1.1.
206  */
207 static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
208 {
209  int n = 0;
210  for (; *buf < buf_end; ++*buf) {
211  n <<= 7;
212  n += **buf & 0x7f;
213  if (!(**buf & 0x80)) {
214  ++*buf;
215  return n;
216  }
217  }
218  return 0;
219 }
220 
221 /**
222  * Based off parse_packed_headers in Vorbis RTP
223  */
224 static int
225 parse_packed_headers(const uint8_t * packed_headers,
226  const uint8_t * packed_headers_end,
227  AVCodecContext * codec, PayloadContext * xiph_data)
228 {
229 
230  unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
231  uint8_t *ptr;
232 
233  if (packed_headers_end - packed_headers < 9) {
234  av_log(codec, AV_LOG_ERROR,
235  "Invalid %"PTRDIFF_SPECIFIER" byte packed header.",
236  packed_headers_end - packed_headers);
237  return AVERROR_INVALIDDATA;
238  }
239 
240  num_packed = bytestream_get_be32(&packed_headers);
241  xiph_data->ident = bytestream_get_be24(&packed_headers);
242  length = bytestream_get_be16(&packed_headers);
243  num_headers = get_base128(&packed_headers, packed_headers_end);
244  length1 = get_base128(&packed_headers, packed_headers_end);
245  length2 = get_base128(&packed_headers, packed_headers_end);
246 
247  if (num_packed != 1 || num_headers > 3) {
248  av_log(codec, AV_LOG_ERROR,
249  "Unimplemented number of headers: %d packed headers, %d headers\n",
250  num_packed, num_headers);
251  return AVERROR_PATCHWELCOME;
252  }
253 
254  if (packed_headers_end - packed_headers != length ||
255  length1 > length || length2 > length - length1) {
256  av_log(codec, AV_LOG_ERROR,
257  "Bad packed header lengths (%d,%d,%"PTRDIFF_SPECIFIER",%d)\n", length1,
258  length2, packed_headers_end - packed_headers, length);
259  return AVERROR_INVALIDDATA;
260  }
261 
262  /* allocate extra space:
263  * -- length/255 +2 for xiphlacing
264  * -- one for the '2' marker
265  * -- FF_INPUT_BUFFER_PADDING_SIZE required */
266  extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
267 
268  if (ff_alloc_extradata(codec, extradata_alloc)) {
269  av_log(codec, AV_LOG_ERROR, "Out of memory\n");
270  return AVERROR(ENOMEM);
271  }
272  ptr = codec->extradata;
273  *ptr++ = 2;
274  ptr += av_xiphlacing(ptr, length1);
275  ptr += av_xiphlacing(ptr, length2);
276  memcpy(ptr, packed_headers, length);
277  ptr += length;
278  codec->extradata_size = ptr - codec->extradata;
279  // clear out remaining parts of the buffer
280  memset(ptr, 0, extradata_alloc - codec->extradata_size);
281 
282  return 0;
283 }
284 
286  AVStream* stream,
287  PayloadContext *xiph_data,
288  const char *attr, const char *value)
289 {
290  AVCodecContext *codec = stream->codec;
291  int result = 0;
292 
293  if (!strcmp(attr, "sampling")) {
294  if (!strcmp(value, "YCbCr-4:2:0")) {
295  codec->pix_fmt = AV_PIX_FMT_YUV420P;
296  } else if (!strcmp(value, "YCbCr-4:4:2")) {
297  codec->pix_fmt = AV_PIX_FMT_YUV422P;
298  } else if (!strcmp(value, "YCbCr-4:4:4")) {
299  codec->pix_fmt = AV_PIX_FMT_YUV444P;
300  } else {
301  av_log(s, AV_LOG_ERROR,
302  "Unsupported pixel format %s\n", attr);
303  return AVERROR_INVALIDDATA;
304  }
305  } else if (!strcmp(attr, "width")) {
306  /* This is an integer between 1 and 1048561
307  * and MUST be in multiples of 16. */
308  codec->width = atoi(value);
309  return 0;
310  } else if (!strcmp(attr, "height")) {
311  /* This is an integer between 1 and 1048561
312  * and MUST be in multiples of 16. */
313  codec->height = atoi(value);
314  return 0;
315  } else if (!strcmp(attr, "delivery-method")) {
316  /* Possible values are: inline, in_band, out_band/specific_name. */
317  return AVERROR_PATCHWELCOME;
318  } else if (!strcmp(attr, "configuration-uri")) {
319  /* NOTE: configuration-uri is supported only under 2 conditions:
320  *--after the delivery-method tag
321  * --with a delivery-method value of out_band */
322  return AVERROR_PATCHWELCOME;
323  } else if (!strcmp(attr, "configuration")) {
324  /* NOTE: configuration is supported only AFTER the delivery-method tag
325  * The configuration value is a base64 encoded packed header */
326  uint8_t *decoded_packet = NULL;
327  int packet_size;
328  size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
329 
330  if (decoded_alloc <= INT_MAX) {
331  decoded_packet = av_malloc(decoded_alloc);
332  if (decoded_packet) {
333  packet_size =
334  av_base64_decode(decoded_packet, value, decoded_alloc);
335 
336  result = parse_packed_headers
337  (decoded_packet, decoded_packet + packet_size, codec,
338  xiph_data);
339  } else {
340  av_log(s, AV_LOG_ERROR,
341  "Out of memory while decoding SDP configuration.\n");
342  result = AVERROR(ENOMEM);
343  }
344  } else {
345  av_log(s, AV_LOG_ERROR, "Packet too large\n");
346  result = AVERROR_INVALIDDATA;
347  }
348  av_free(decoded_packet);
349  }
350  return result;
351 }
352 
353 static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
354  PayloadContext *data, const char *line)
355 {
356  const char *p;
357 
358  if (st_index < 0)
359  return 0;
360 
361  if (av_strstart(line, "fmtp:", &p)) {
362  return ff_parse_fmtp(s, s->streams[st_index], data, p,
364  }
365 
366  return 0;
367 }
368 
370  .enc_name = "theora",
371  .codec_type = AVMEDIA_TYPE_VIDEO,
372  .codec_id = AV_CODEC_ID_THEORA,
373  .priv_data_size = sizeof(PayloadContext),
374  .parse_sdp_a_line = xiph_parse_sdp_line,
375  .close = xiph_close_context,
377 };
378 
380  .enc_name = "vorbis",
381  .codec_type = AVMEDIA_TYPE_AUDIO,
382  .codec_id = AV_CODEC_ID_VORBIS,
383  .need_parsing = AVSTREAM_PARSE_HEADERS,
384  .priv_data_size = sizeof(PayloadContext),
385  .parse_sdp_a_line = xiph_parse_sdp_line,
386  .close = xiph_close_context,
388 };