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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 "internal.h"
37 #include "rtpdec.h"
38 #include "rtpdec_formats.h"
39 
40 /**
41  * RTP/Xiph specific private data.
42  */
43 struct PayloadContext {
44  unsigned ident; ///< 24-bit stream configuration identifier
45  uint32_t timestamp;
46  AVIOContext* fragment; ///< buffer for split payloads
50 };
51 
53 {
54  return av_mallocz(sizeof(PayloadContext));
55 }
56 
58 {
59  if (data->fragment) {
60  uint8_t* p;
61  avio_close_dyn_buf(data->fragment, &p);
62  av_free(p);
63  data->fragment = NULL;
64  }
65 }
66 
68 {
70  av_freep(&data->split_buf);
71  av_freep(&data);
72 }
73 
74 static av_cold int xiph_vorbis_init(AVFormatContext *ctx, int st_index,
76 {
77  if (st_index < 0)
78  return 0;
80  return 0;
81 }
82 
83 
85  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
86  const uint8_t *buf, int len, uint16_t seq,
87  int flags)
88 {
89 
90  int ident, fragmented, tdt, num_pkts, pkt_len;
91 
92  if (!buf) {
93  if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||
94  data->split_pkts <= 0) {
95  av_log(ctx, AV_LOG_ERROR, "No more data to return\n");
96  return AVERROR_INVALIDDATA;
97  }
98  pkt_len = AV_RB16(data->split_buf + data->split_pos);
99  data->split_pos += 2;
100  if (data->split_pos + pkt_len > data->split_buf_len) {
101  av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");
102  return AVERROR_INVALIDDATA;
103  }
104  if (av_new_packet(pkt, pkt_len)) {
105  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
106  return AVERROR(ENOMEM);
107  }
108  pkt->stream_index = st->index;
109  memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);
110  data->split_pos += pkt_len;
111  data->split_pkts--;
112  return data->split_pkts > 0;
113  }
114 
115  if (len < 6) {
116  av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
117  return AVERROR_INVALIDDATA;
118  }
119 
120  // read xiph rtp headers
121  ident = AV_RB24(buf);
122  fragmented = buf[3] >> 6;
123  tdt = (buf[3] >> 4) & 3;
124  num_pkts = buf[3] & 0xf;
125  pkt_len = AV_RB16(buf + 4);
126 
127  if (pkt_len > len - 6) {
128  av_log(ctx, AV_LOG_ERROR,
129  "Invalid packet length %d in %d byte packet\n", pkt_len,
130  len);
131  return AVERROR_INVALIDDATA;
132  }
133 
134  if (ident != data->ident) {
135  av_log(ctx, AV_LOG_ERROR,
136  "Unimplemented Xiph SDP configuration change detected\n");
137  return AVERROR_PATCHWELCOME;
138  }
139 
140  if (tdt) {
141  av_log(ctx, AV_LOG_ERROR,
142  "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
143  fragmented, tdt, num_pkts);
144  return AVERROR_PATCHWELCOME;
145  }
146 
147  buf += 6; // move past header bits
148  len -= 6;
149 
150  if (fragmented == 0) {
151  if (av_new_packet(pkt, pkt_len)) {
152  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
153  return AVERROR(ENOMEM);
154  }
155  pkt->stream_index = st->index;
156  memcpy(pkt->data, buf, pkt_len);
157  buf += pkt_len;
158  len -= pkt_len;
159  num_pkts--;
160 
161  if (num_pkts > 0) {
162  if (len > data->split_buf_size || !data->split_buf) {
163  av_freep(&data->split_buf);
164  data->split_buf_size = 2 * len;
165  data->split_buf = av_malloc(data->split_buf_size);
166  if (!data->split_buf) {
167  av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
168  av_free_packet(pkt);
169  return AVERROR(ENOMEM);
170  }
171  }
172  memcpy(data->split_buf, buf, len);
173  data->split_buf_len = len;
174  data->split_pos = 0;
175  data->split_pkts = num_pkts;
176  return 1;
177  }
178 
179  return 0;
180 
181  } else if (fragmented == 1) {
182  // start of xiph data fragment
183  int res;
184 
185  // end packet has been lost somewhere, so drop buffered data
187 
188  if((res = avio_open_dyn_buf(&data->fragment)) < 0)
189  return res;
190 
191  avio_write(data->fragment, buf, pkt_len);
192  data->timestamp = *timestamp;
193 
194  } else {
195  av_assert1(fragmented < 4);
196  if (data->timestamp != *timestamp) {
197  // skip if fragmented timestamp is incorrect;
198  // a start packet has been lost somewhere
200  av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
201  return AVERROR_INVALIDDATA;
202  }
203  if (!data->fragment) {
204  av_log(ctx, AV_LOG_WARNING,
205  "Received packet without a start fragment; dropping.\n");
206  return AVERROR(EAGAIN);
207  }
208 
209  // copy data to fragment buffer
210  avio_write(data->fragment, buf, pkt_len);
211 
212  if (fragmented == 3) {
213  // end of xiph data packet
214  int ret = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
215  if (ret < 0) {
216  av_log(ctx, AV_LOG_ERROR,
217  "Error occurred when getting fragment buffer.");
218  return ret;
219  }
220 
221  return 0;
222  }
223  }
224 
225  return AVERROR(EAGAIN);
226 }
227 
228 /**
229  * Length encoding described in RFC5215 section 3.1.1.
230  */
231 static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
232 {
233  int n = 0;
234  for (; *buf < buf_end; ++*buf) {
235  n <<= 7;
236  n += **buf & 0x7f;
237  if (!(**buf & 0x80)) {
238  ++*buf;
239  return n;
240  }
241  }
242  return 0;
243 }
244 
245 /**
246  * Based off parse_packed_headers in Vorbis RTP
247  */
248 static int
249 parse_packed_headers(const uint8_t * packed_headers,
250  const uint8_t * packed_headers_end,
251  AVCodecContext * codec, PayloadContext * xiph_data)
252 {
253 
254  unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
255  uint8_t *ptr;
256 
257  if (packed_headers_end - packed_headers < 9) {
258  av_log(codec, AV_LOG_ERROR,
259  "Invalid %"PTRDIFF_SPECIFIER" byte packed header.",
260  packed_headers_end - packed_headers);
261  return AVERROR_INVALIDDATA;
262  }
263 
264  num_packed = bytestream_get_be32(&packed_headers);
265  xiph_data->ident = bytestream_get_be24(&packed_headers);
266  length = bytestream_get_be16(&packed_headers);
267  num_headers = get_base128(&packed_headers, packed_headers_end);
268  length1 = get_base128(&packed_headers, packed_headers_end);
269  length2 = get_base128(&packed_headers, packed_headers_end);
270 
271  if (num_packed != 1 || num_headers > 3) {
272  av_log(codec, AV_LOG_ERROR,
273  "Unimplemented number of headers: %d packed headers, %d headers\n",
274  num_packed, num_headers);
275  return AVERROR_PATCHWELCOME;
276  }
277 
278  if (packed_headers_end - packed_headers != length ||
279  length1 > length || length2 > length - length1) {
280  av_log(codec, AV_LOG_ERROR,
281  "Bad packed header lengths (%d,%d,%"PTRDIFF_SPECIFIER",%d)\n", length1,
282  length2, packed_headers_end - packed_headers, length);
283  return AVERROR_INVALIDDATA;
284  }
285 
286  /* allocate extra space:
287  * -- length/255 +2 for xiphlacing
288  * -- one for the '2' marker
289  * -- FF_INPUT_BUFFER_PADDING_SIZE required */
290  extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
291 
292  if (ff_alloc_extradata(codec, extradata_alloc)) {
293  av_log(codec, AV_LOG_ERROR, "Out of memory\n");
294  return AVERROR(ENOMEM);
295  }
296  ptr = codec->extradata;
297  *ptr++ = 2;
298  ptr += av_xiphlacing(ptr, length1);
299  ptr += av_xiphlacing(ptr, length2);
300  memcpy(ptr, packed_headers, length);
301  ptr += length;
302  codec->extradata_size = ptr - codec->extradata;
303  // clear out remaining parts of the buffer
304  memset(ptr, 0, extradata_alloc - codec->extradata_size);
305 
306  return 0;
307 }
308 
310  AVStream* stream,
311  PayloadContext *xiph_data,
312  char *attr, char *value)
313 {
314  AVCodecContext *codec = stream->codec;
315  int result = 0;
316 
317  if (!strcmp(attr, "sampling")) {
318  if (!strcmp(value, "YCbCr-4:2:0")) {
319  codec->pix_fmt = AV_PIX_FMT_YUV420P;
320  } else if (!strcmp(value, "YCbCr-4:4:2")) {
321  codec->pix_fmt = AV_PIX_FMT_YUV422P;
322  } else if (!strcmp(value, "YCbCr-4:4:4")) {
323  codec->pix_fmt = AV_PIX_FMT_YUV444P;
324  } else {
325  av_log(s, AV_LOG_ERROR,
326  "Unsupported pixel format %s\n", attr);
327  return AVERROR_INVALIDDATA;
328  }
329  } else if (!strcmp(attr, "width")) {
330  /* This is an integer between 1 and 1048561
331  * and MUST be in multiples of 16. */
332  codec->width = atoi(value);
333  return 0;
334  } else if (!strcmp(attr, "height")) {
335  /* This is an integer between 1 and 1048561
336  * and MUST be in multiples of 16. */
337  codec->height = atoi(value);
338  return 0;
339  } else if (!strcmp(attr, "delivery-method")) {
340  /* Possible values are: inline, in_band, out_band/specific_name. */
341  return AVERROR_PATCHWELCOME;
342  } else if (!strcmp(attr, "configuration-uri")) {
343  /* NOTE: configuration-uri is supported only under 2 conditions:
344  *--after the delivery-method tag
345  * --with a delivery-method value of out_band */
346  return AVERROR_PATCHWELCOME;
347  } else if (!strcmp(attr, "configuration")) {
348  /* NOTE: configuration is supported only AFTER the delivery-method tag
349  * The configuration value is a base64 encoded packed header */
350  uint8_t *decoded_packet = NULL;
351  int packet_size;
352  size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
353 
354  if (decoded_alloc <= INT_MAX) {
355  decoded_packet = av_malloc(decoded_alloc);
356  if (decoded_packet) {
357  packet_size =
358  av_base64_decode(decoded_packet, value, decoded_alloc);
359 
360  result = parse_packed_headers
361  (decoded_packet, decoded_packet + packet_size, codec,
362  xiph_data);
363  } else {
364  av_log(s, AV_LOG_ERROR,
365  "Out of memory while decoding SDP configuration.\n");
366  result = AVERROR(ENOMEM);
367  }
368  } else {
369  av_log(s, AV_LOG_ERROR, "Packet too large\n");
370  result = AVERROR_INVALIDDATA;
371  }
372  av_free(decoded_packet);
373  }
374  return result;
375 }
376 
377 static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
378  PayloadContext *data, const char *line)
379 {
380  const char *p;
381 
382  if (st_index < 0)
383  return 0;
384 
385  if (av_strstart(line, "fmtp:", &p)) {
386  return ff_parse_fmtp(s, s->streams[st_index], data, p,
388  }
389 
390  return 0;
391 }
392 
394  .enc_name = "theora",
395  .codec_type = AVMEDIA_TYPE_VIDEO,
396  .codec_id = AV_CODEC_ID_THEORA,
397  .parse_sdp_a_line = xiph_parse_sdp_line,
398  .alloc = xiph_new_context,
399  .free = xiph_free_context,
400  .parse_packet = xiph_handle_packet
401 };
402 
404  .enc_name = "vorbis",
405  .codec_type = AVMEDIA_TYPE_AUDIO,
406  .codec_id = AV_CODEC_ID_VORBIS,
407  .init = xiph_vorbis_init,
408  .parse_sdp_a_line = xiph_parse_sdp_line,
409  .alloc = xiph_new_context,
410  .free = xiph_free_context,
411  .parse_packet = xiph_handle_packet
412 };