rtpdec_asf.c
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1 /*
2  * Microsoft RTP/ASF support.
3  * Copyright (c) 2008 Ronald S. Bultje
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
28 #include "libavutil/base64.h"
29 #include "libavutil/avstring.h"
30 #include "libavutil/intreadwrite.h"
31 #include "rtp.h"
32 #include "rtpdec_formats.h"
33 #include "rtsp.h"
34 #include "asf.h"
35 #include "avio_internal.h"
36 #include "internal.h"
37 
45 static int rtp_asf_fix_header(uint8_t *buf, int len)
46 {
47  uint8_t *p = buf, *end = buf + len;
48 
49  if (len < sizeof(ff_asf_guid) * 2 + 22 ||
50  memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
51  return -1;
52  }
53  p += sizeof(ff_asf_guid) + 14;
54  do {
55  uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
56  if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
57  if (chunksize > end - p)
58  return -1;
59  p += chunksize;
60  continue;
61  }
62 
63  /* skip most of the file header, to min_pktsize */
64  p += 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;
65  if (p + 8 <= end && AV_RL32(p) == AV_RL32(p + 4)) {
66  /* and set that to zero */
67  AV_WL32(p, 0);
68  return 0;
69  }
70  break;
71  } while (end - p >= sizeof(ff_asf_guid) + 8);
72 
73  return -1;
74 }
75 
82 static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)
83 {
84  return AVERROR(EAGAIN);
85 }
86 
87 static void init_packetizer(AVIOContext *pb, uint8_t *buf, int len)
88 {
89  ffio_init_context(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);
90 
91  /* this "fills" the buffer with its current content */
92  pb->pos = len;
93  pb->buf_end = buf + len;
94 }
95 
97 {
98  int ret = 0;
99  if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
100  AVIOContext pb;
101  RTSPState *rt = s->priv_data;
102  int len = strlen(p) * 6 / 8;
103  char *buf = av_mallocz(len);
104  av_base64_decode(buf, p, len);
105 
106  if (rtp_asf_fix_header(buf, len) < 0)
107  av_log(s, AV_LOG_ERROR,
108  "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
109  init_packetizer(&pb, buf, len);
110  if (rt->asf_ctx) {
112  }
113  if (!(rt->asf_ctx = avformat_alloc_context()))
114  return AVERROR(ENOMEM);
115  rt->asf_ctx->pb = &pb;
116  ret = avformat_open_input(&rt->asf_ctx, "", &ff_asf_demuxer, NULL);
117  if (ret < 0)
118  return ret;
119  av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);
120  rt->asf_pb_pos = avio_tell(&pb);
121  av_free(buf);
122  rt->asf_ctx->pb = NULL;
123  }
124  return ret;
125 }
126 
127 static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
128  PayloadContext *asf, const char *line)
129 {
130  if (av_strstart(line, "stream:", &line)) {
131  RTSPState *rt = s->priv_data;
132 
133  s->streams[stream_index]->id = strtol(line, NULL, 10);
134 
135  if (rt->asf_ctx) {
136  int i;
137 
138  for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
139  if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
140  *s->streams[stream_index]->codec =
141  *rt->asf_ctx->streams[i]->codec;
142  rt->asf_ctx->streams[i]->codec->extradata_size = 0;
143  rt->asf_ctx->streams[i]->codec->extradata = NULL;
144  avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000);
145  }
146  }
147  }
148  }
149 
150  return 0;
151 }
152 
153 struct PayloadContext {
155  uint8_t *buf;
156 };
157 
164  AVStream *st, AVPacket *pkt,
165  uint32_t *timestamp,
166  const uint8_t *buf, int len, int flags)
167 {
168  AVIOContext *pb = &asf->pb;
169  int res, mflags, len_off;
170  RTSPState *rt = s->priv_data;
171 
172  if (!rt->asf_ctx)
173  return -1;
174 
175  if (len > 0) {
176  int off, out_len = 0;
177 
178  if (len < 4)
179  return -1;
180 
181  av_freep(&asf->buf);
182 
183  ffio_init_context(pb, buf, len, 0, NULL, NULL, NULL, NULL);
184 
185  while (avio_tell(pb) + 4 < len) {
186  int start_off = avio_tell(pb);
187 
188  mflags = avio_r8(pb);
189  if (mflags & 0x80)
190  flags |= RTP_FLAG_KEY;
191  len_off = avio_rb24(pb);
192  if (mflags & 0x20)
193  avio_skip(pb, 4);
194  if (mflags & 0x10)
195  avio_skip(pb, 4);
196  if (mflags & 0x8)
197  avio_skip(pb, 4);
198  off = avio_tell(pb);
199 
200  if (!(mflags & 0x40)) {
207  if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) {
208  uint8_t *p;
209  avio_close_dyn_buf(asf->pktbuf, &p);
210  asf->pktbuf = NULL;
211  av_free(p);
212  }
213  if (!len_off && !asf->pktbuf &&
214  (res = avio_open_dyn_buf(&asf->pktbuf)) < 0)
215  return res;
216  if (!asf->pktbuf)
217  return AVERROR(EIO);
218 
219  avio_write(asf->pktbuf, buf + off, len - off);
220  avio_skip(pb, len - off);
221  if (!(flags & RTP_FLAG_MARKER))
222  return -1;
223  out_len = avio_close_dyn_buf(asf->pktbuf, &asf->buf);
224  asf->pktbuf = NULL;
225  } else {
234  int cur_len = start_off + len_off - off;
235  int prev_len = out_len;
236  void *newmem;
237  out_len += cur_len;
238  if (FFMIN(cur_len, len - off) < 0)
239  return -1;
240  newmem = av_realloc(asf->buf, out_len);
241  if (!newmem)
242  return -1;
243  asf->buf = newmem;
244  memcpy(asf->buf + prev_len, buf + off,
245  FFMIN(cur_len, len - off));
246  avio_skip(pb, cur_len);
247  }
248  }
249 
250  init_packetizer(pb, asf->buf, out_len);
251  pb->pos += rt->asf_pb_pos;
252  pb->eof_reached = 0;
253  rt->asf_ctx->pb = pb;
254  }
255 
256  for (;;) {
257  int i;
258 
259  res = av_read_packet(rt->asf_ctx, pkt);
260  rt->asf_pb_pos = avio_tell(pb);
261  if (res != 0)
262  break;
263  for (i = 0; i < s->nb_streams; i++) {
264  if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
265  pkt->stream_index = i;
266  return 1; // FIXME: return 0 if last packet
267  }
268  }
269  av_free_packet(pkt);
270  }
271 
272  return res == 1 ? -1 : res;
273 }
274 
276 {
277  return av_mallocz(sizeof(PayloadContext));
278 }
279 
281 {
282  if (asf->pktbuf) {
283  uint8_t *p = NULL;
284  avio_close_dyn_buf(asf->pktbuf, &p);
285  asf->pktbuf = NULL;
286  av_free(p);
287  }
288  av_freep(&asf->buf);
289  av_free(asf);
290 }
291 
292 #define RTP_ASF_HANDLER(n, s, t) \
293 RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
294  .enc_name = s, \
295  .codec_type = t, \
296  .codec_id = CODEC_ID_NONE, \
297  .parse_sdp_a_line = asfrtp_parse_sdp_line, \
298  .alloc = asfrtp_new_context, \
299  .free = asfrtp_free_context, \
300  .parse_packet = asfrtp_parse_packet, \
301 }
302 
303 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf", AVMEDIA_TYPE_VIDEO);
304 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf", AVMEDIA_TYPE_AUDIO);