FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
rtpdec_qt.c
Go to the documentation of this file.
1 /*
2  * RTP/Quicktime support.
3  * Copyright (c) 2009 Ronald S. Bultje
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 Quicktime-style RTP support
25  * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
26  */
27 
28 #include "avformat.h"
29 #include "internal.h"
30 #include "avio_internal.h"
31 #include "rtp.h"
32 #include "rtpdec.h"
33 #include "isom.h"
34 #include "libavcodec/get_bits.h"
35 
36 struct PayloadContext {
39  uint32_t timestamp;
40 };
41 
43  AVStream *st, AVPacket *pkt,
44  uint32_t *timestamp, const uint8_t *buf,
45  int len, uint16_t seq, int flags)
46 {
47  AVIOContext pb;
48  GetBitContext gb;
49  int packing_scheme, has_payload_desc, has_packet_info, alen,
50  has_marker_bit = flags & RTP_FLAG_MARKER;
51 
52  if (qt->remaining) {
53  int num = qt->pkt.size / qt->bytes_per_frame;
54 
55  if (av_new_packet(pkt, qt->bytes_per_frame))
56  return AVERROR(ENOMEM);
57  pkt->stream_index = st->index;
58  pkt->flags = qt->pkt.flags;
59  memcpy(pkt->data,
60  &qt->pkt.data[(num - qt->remaining) * qt->bytes_per_frame],
61  qt->bytes_per_frame);
62  if (--qt->remaining == 0) {
63  av_freep(&qt->pkt.data);
64  qt->pkt.size = 0;
65  }
66  return qt->remaining > 0;
67  }
68 
69  /**
70  * The RTP payload is described in:
71  * http://developer.apple.com/quicktime/icefloe/dispatch026.html
72  */
73  init_get_bits(&gb, buf, len << 3);
74  ffio_init_context(&pb, (uint8_t*)buf, len, 0, NULL, NULL, NULL, NULL);
75 
76  if (len < 4)
77  return AVERROR_INVALIDDATA;
78 
79  skip_bits(&gb, 4); // version
80  if ((packing_scheme = get_bits(&gb, 2)) == 0)
81  return AVERROR_INVALIDDATA;
82  if (get_bits1(&gb))
83  flags |= RTP_FLAG_KEY;
84  has_payload_desc = get_bits1(&gb);
85  has_packet_info = get_bits1(&gb);
86  skip_bits(&gb, 23); // reserved:7, cache payload info:1, payload ID:15
87 
88  if (has_payload_desc) {
89  int data_len, pos, is_start, is_finish;
90  uint32_t tag;
91 
92  pos = get_bits_count(&gb) >> 3;
93  if (pos + 12 > len)
94  return AVERROR_INVALIDDATA;
95 
96  skip_bits(&gb, 2); // has non-I frames:1, is sparse:1
97  is_start = get_bits1(&gb);
98  is_finish = get_bits1(&gb);
99  if (!is_start || !is_finish) {
100  avpriv_request_sample(s, "RTP-X-QT with payload description "
101  "split over several packets");
102  return AVERROR_PATCHWELCOME;
103  }
104  skip_bits(&gb, 12); // reserved
105  data_len = get_bits(&gb, 16);
106 
107  avio_seek(&pb, pos + 4, SEEK_SET);
108  tag = avio_rl32(&pb);
109  if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
110  tag != MKTAG('v','i','d','e')) ||
112  tag != MKTAG('s','o','u','n')))
113  return AVERROR_INVALIDDATA;
114  avpriv_set_pts_info(st, 32, 1, avio_rb32(&pb));
115 
116  if (pos + data_len > len)
117  return AVERROR_INVALIDDATA;
118  /* TLVs */
119  while (avio_tell(&pb) + 4 < pos + data_len) {
120  int tlv_len = avio_rb16(&pb);
121  tag = avio_rl16(&pb);
122  if (avio_tell(&pb) + tlv_len > pos + data_len)
123  return AVERROR_INVALIDDATA;
124 
125 #define MKTAG16(a,b) MKTAG(a,b,0,0)
126  switch (tag) {
127  case MKTAG16('s','d'): {
128  MOVStreamContext *msc;
129  void *priv_data = st->priv_data;
130  int nb_streams = s->nb_streams;
131  MOVContext *mc = av_mallocz(sizeof(*mc));
132  if (!mc)
133  return AVERROR(ENOMEM);
134  mc->fc = s;
135  st->priv_data = msc = av_mallocz(sizeof(MOVStreamContext));
136  if (!msc) {
137  av_free(mc);
138  st->priv_data = priv_data;
139  return AVERROR(ENOMEM);
140  }
141  /* ff_mov_read_stsd_entries updates stream s->nb_streams-1,
142  * so set it temporarily to indicate which stream to update. */
143  s->nb_streams = st->index + 1;
144  ff_mov_read_stsd_entries(mc, &pb, 1);
145  qt->bytes_per_frame = msc->bytes_per_frame;
146  av_free(msc);
147  av_free(mc);
148  st->priv_data = priv_data;
149  s->nb_streams = nb_streams;
150  break;
151  }
152  default:
153  avio_skip(&pb, tlv_len);
154  break;
155  }
156  }
157 
158  /* 32-bit alignment */
159  avio_skip(&pb, ((avio_tell(&pb) + 3) & ~3) - avio_tell(&pb));
160  } else
161  avio_seek(&pb, 4, SEEK_SET);
162 
163  if (has_packet_info) {
164  avpriv_request_sample(s, "RTP-X-QT with packet-specific info");
165  return AVERROR_PATCHWELCOME;
166  }
167 
168  alen = len - avio_tell(&pb);
169  if (alen <= 0)
170  return AVERROR_INVALIDDATA;
171 
172  switch (packing_scheme) {
173  case 3: /* one data packet spread over 1 or multiple RTP packets */
174  if (qt->pkt.size > 0 && qt->timestamp == *timestamp) {
175  int err;
176  if ((err = av_reallocp(&qt->pkt.data, qt->pkt.size + alen +
178  qt->pkt.size = 0;
179  return err;
180  }
181  } else {
182  av_freep(&qt->pkt.data);
183  av_init_packet(&qt->pkt);
184  qt->pkt.data = av_realloc(NULL, alen + FF_INPUT_BUFFER_PADDING_SIZE);
185  if (!qt->pkt.data)
186  return AVERROR(ENOMEM);
187  qt->pkt.size = 0;
188  qt->timestamp = *timestamp;
189  }
190  memcpy(qt->pkt.data + qt->pkt.size, buf + avio_tell(&pb), alen);
191  qt->pkt.size += alen;
192  if (has_marker_bit) {
193  int ret = av_packet_from_data(pkt, qt->pkt.data, qt->pkt.size);
194  if (ret < 0)
195  return ret;
196 
197  qt->pkt.size = 0;
198  qt->pkt.data = NULL;
199  pkt->flags = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;
200  pkt->stream_index = st->index;
201  memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
202  return 0;
203  }
204  return AVERROR(EAGAIN);
205 
206  case 1: /* constant packet size, multiple packets per RTP packet */
207  if (qt->bytes_per_frame == 0 ||
208  alen % qt->bytes_per_frame != 0)
209  return AVERROR_INVALIDDATA; /* wrongly padded */
210  qt->remaining = (alen / qt->bytes_per_frame) - 1;
211  if (av_new_packet(pkt, qt->bytes_per_frame))
212  return AVERROR(ENOMEM);
213  memcpy(pkt->data, buf + avio_tell(&pb), qt->bytes_per_frame);
214  pkt->flags = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;
215  pkt->stream_index = st->index;
216  if (qt->remaining > 0) {
217  av_freep(&qt->pkt.data);
218  qt->pkt.data = av_realloc(NULL, qt->remaining * qt->bytes_per_frame);
219  if (!qt->pkt.data) {
220  av_free_packet(pkt);
221  return AVERROR(ENOMEM);
222  }
223  qt->pkt.size = qt->remaining * qt->bytes_per_frame;
224  memcpy(qt->pkt.data,
225  buf + avio_tell(&pb) + qt->bytes_per_frame,
226  qt->remaining * qt->bytes_per_frame);
227  qt->pkt.flags = pkt->flags;
228  return 1;
229  }
230  return 0;
231 
232  default: /* unimplemented */
233  avpriv_request_sample(NULL, "RTP-X-QT with packing scheme 2");
234  return AVERROR_PATCHWELCOME;
235  }
236 }
237 
239 {
240  return av_mallocz(sizeof(PayloadContext));
241 }
242 
243 static void qt_rtp_free(PayloadContext *qt)
244 {
245  av_freep(&qt->pkt.data);
246  av_free(qt);
247 }
248 
249 #define RTP_QT_HANDLER(m, n, s, t) \
250 RTPDynamicProtocolHandler ff_ ## m ## _rtp_ ## n ## _handler = { \
251  .enc_name = s, \
252  .codec_type = t, \
253  .codec_id = AV_CODEC_ID_NONE, \
254  .alloc = qt_rtp_new, \
255  .free = qt_rtp_free, \
256  .parse_packet = qt_rtp_parse_packet, \
257 }
258 
259 RTP_QT_HANDLER(qt, vid, "X-QT", AVMEDIA_TYPE_VIDEO);
260 RTP_QT_HANDLER(qt, aud, "X-QT", AVMEDIA_TYPE_AUDIO);
261 RTP_QT_HANDLER(quicktime, vid, "X-QUICKTIME", AVMEDIA_TYPE_VIDEO);
262 RTP_QT_HANDLER(quicktime, aud, "X-QUICKTIME", AVMEDIA_TYPE_AUDIO);