FFmpeg  2.1.1
rtpdec_asf.c
Go to the documentation of this file.
1 /*
2  * Microsoft RTP/ASF support.
3  * Copyright (c) 2008 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 Microsoft RTP/ASF support
25  * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
26  */
27 
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 
38 /**
39  * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
40  * contain any padding. Unfortunately, the header min/max_pktsize are not
41  * updated (thus making min_pktsize invalid). Here, we "fix" these faulty
42  * min_pktsize values in the ASF file header.
43  * @return 0 on success, <0 on failure (currently -1).
44  */
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 
76 /**
77  * The following code is basically a buffered AVIOContext,
78  * with the added benefit of returning -EAGAIN (instead of 0)
79  * on packet boundaries, such that the ASF demuxer can return
80  * safely and resume business at the next packet.
81  */
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  AVDictionary *opts = NULL;
103  int len = strlen(p) * 6 / 8;
104  char *buf = av_mallocz(len);
105  av_base64_decode(buf, p, len);
106 
107  if (rtp_asf_fix_header(buf, len) < 0)
108  av_log(s, AV_LOG_ERROR,
109  "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
110  init_packetizer(&pb, buf, len);
111  if (rt->asf_ctx) {
113  }
114  if (!(rt->asf_ctx = avformat_alloc_context()))
115  return AVERROR(ENOMEM);
116  rt->asf_ctx->pb = &pb;
117  av_dict_set(&opts, "no_resync_search", "1", 0);
118  ret = avformat_open_input(&rt->asf_ctx, "", &ff_asf_demuxer, &opts);
119  av_dict_free(&opts);
120  if (ret < 0)
121  return ret;
122  av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);
123  rt->asf_pb_pos = avio_tell(&pb);
124  av_free(buf);
125  rt->asf_ctx->pb = NULL;
126  }
127  return ret;
128 }
129 
130 static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
131  PayloadContext *asf, const char *line)
132 {
133  if (stream_index < 0)
134  return 0;
135  if (av_strstart(line, "stream:", &line)) {
136  RTSPState *rt = s->priv_data;
137 
138  s->streams[stream_index]->id = strtol(line, NULL, 10);
139 
140  if (rt->asf_ctx) {
141  int i;
142 
143  for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
144  if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
145  *s->streams[stream_index]->codec =
146  *rt->asf_ctx->streams[i]->codec;
147  rt->asf_ctx->streams[i]->codec->extradata_size = 0;
148  rt->asf_ctx->streams[i]->codec->extradata = NULL;
149  avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000);
150  }
151  }
152  }
153  }
154 
155  return 0;
156 }
157 
158 struct PayloadContext {
161 };
162 
163 /**
164  * @return 0 when a packet was written into /p pkt, and no more data is left;
165  * 1 when a packet was written into /p pkt, and more packets might be left;
166  * <0 when not enough data was provided to return a full packet, or on error.
167  */
169  AVStream *st, AVPacket *pkt,
170  uint32_t *timestamp,
171  const uint8_t *buf, int len, uint16_t seq,
172  int flags)
173 {
174  AVIOContext *pb = &asf->pb;
175  int res, mflags, len_off;
176  RTSPState *rt = s->priv_data;
177 
178  if (!rt->asf_ctx)
179  return -1;
180 
181  if (len > 0) {
182  int off, out_len = 0;
183 
184  if (len < 4)
185  return -1;
186 
187  av_freep(&asf->buf);
188 
189  ffio_init_context(pb, buf, len, 0, NULL, NULL, NULL, NULL);
190 
191  while (avio_tell(pb) + 4 < len) {
192  int start_off = avio_tell(pb);
193 
194  mflags = avio_r8(pb);
195  if (mflags & 0x80)
196  flags |= RTP_FLAG_KEY;
197  len_off = avio_rb24(pb);
198  if (mflags & 0x20) /**< relative timestamp */
199  avio_skip(pb, 4);
200  if (mflags & 0x10) /**< has duration */
201  avio_skip(pb, 4);
202  if (mflags & 0x8) /**< has location ID */
203  avio_skip(pb, 4);
204  off = avio_tell(pb);
205 
206  if (!(mflags & 0x40)) {
207  /**
208  * If 0x40 is not set, the len_off field specifies an offset
209  * of this packet's payload data in the complete (reassembled)
210  * ASF packet. This is used to spread one ASF packet over
211  * multiple RTP packets.
212  */
213  if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) {
214  uint8_t *p;
215  avio_close_dyn_buf(asf->pktbuf, &p);
216  asf->pktbuf = NULL;
217  av_free(p);
218  }
219  if (!len_off && !asf->pktbuf &&
220  (res = avio_open_dyn_buf(&asf->pktbuf)) < 0)
221  return res;
222  if (!asf->pktbuf)
223  return AVERROR(EIO);
224 
225  avio_write(asf->pktbuf, buf + off, len - off);
226  avio_skip(pb, len - off);
227  if (!(flags & RTP_FLAG_MARKER))
228  return -1;
229  out_len = avio_close_dyn_buf(asf->pktbuf, &asf->buf);
230  asf->pktbuf = NULL;
231  } else {
232  /**
233  * If 0x40 is set, the len_off field specifies the length of
234  * the next ASF packet that can be read from this payload
235  * data alone. This is commonly the same as the payload size,
236  * but could be less in case of packet splitting (i.e.
237  * multiple ASF packets in one RTP packet).
238  */
239 
240  int cur_len = start_off + len_off - off;
241  int prev_len = out_len;
242  out_len += cur_len;
243  if (FFMIN(cur_len, len - off) < 0)
244  return -1;
245  if ((res = av_reallocp(&asf->buf, out_len)) < 0)
246  return res;
247  memcpy(asf->buf + prev_len, buf + off,
248  FFMIN(cur_len, len - off));
249  avio_skip(pb, cur_len);
250  }
251  }
252 
253  init_packetizer(pb, asf->buf, out_len);
254  pb->pos += rt->asf_pb_pos;
255  pb->eof_reached = 0;
256  rt->asf_ctx->pb = pb;
257  }
258 
259  for (;;) {
260  int i;
261 
262  res = ff_read_packet(rt->asf_ctx, pkt);
263  rt->asf_pb_pos = avio_tell(pb);
264  if (res != 0)
265  break;
266  for (i = 0; i < s->nb_streams; i++) {
267  if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
268  pkt->stream_index = i;
269  return 1; // FIXME: return 0 if last packet
270  }
271  }
272  av_free_packet(pkt);
273  }
274 
275  return res == 1 ? -1 : res;
276 }
277 
279 {
280  return av_mallocz(sizeof(PayloadContext));
281 }
282 
284 {
285  if (asf->pktbuf) {
286  uint8_t *p = NULL;
287  avio_close_dyn_buf(asf->pktbuf, &p);
288  asf->pktbuf = NULL;
289  av_free(p);
290  }
291  av_freep(&asf->buf);
292  av_free(asf);
293 }
294 
295 #define RTP_ASF_HANDLER(n, s, t) \
296 RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
297  .enc_name = s, \
298  .codec_type = t, \
299  .codec_id = AV_CODEC_ID_NONE, \
300  .parse_sdp_a_line = asfrtp_parse_sdp_line, \
301  .alloc = asfrtp_new_context, \
302  .free = asfrtp_free_context, \
303  .parse_packet = asfrtp_parse_packet, \
304 }
305 
306 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf", AVMEDIA_TYPE_VIDEO);
307 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf", AVMEDIA_TYPE_AUDIO);
const ff_asf_guid ff_asf_header
Definition: asf.c:23
int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
Parse a Windows Media Server-specific SDP line.
Definition: rtpdec_asf.c:96
const char * s
Definition: avisynth_c.h:668
Bytestream IO Context.
Definition: avio.h:68
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:279
int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:487
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:3922
RTP/JPEG specific private data.
Definition: rdt.c:83
#define AV_WL32(p, darg)
Definition: intreadwrite.h:282
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:686
void av_log(void *avcl, int level, const char *fmt,...) av_printf_format(3
Send the specified message to the log if the level is less than or equal to the current av_log_level...
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:173
uint8_t * buf
the temporary storage buffer
Definition: rtpdec_asf.c:160
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:471
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1254
void av_freep(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:234
Format I/O context.
Definition: avformat.h:968
static uint8_t * res
Definition: ffhash.c:43
static int rtp_asf_fix_header(uint8_t *buf, int len)
From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not contain any padding...
Definition: rtpdec_asf.c:45
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:67
int id
Format-specific stream ID.
Definition: avformat.h:674
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:248
int av_reallocp(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:183
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:617
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1030
void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
Definition: dict.c:176
Private data for the RTSP demuxer.
Definition: rtsp.h:217
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: avcodec.h:4147
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:219
static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags)
Definition: rtpdec_asf.c:168
#define RTP_FLAG_MARKER
RTP marker bit was set for this packet.
Definition: rtpdec.h:93
static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)
The following code is basically a buffered AVIOContext, with the added benefit of returning -EAGAIN (...
Definition: rtpdec_asf.c:82
void * priv_data
Format private data.
Definition: avformat.h:988
void av_dict_free(AVDictionary **m)
Free all the memory allocated for an AVDictionary struct and all keys and values. ...
Definition: dict.c:162
Definition: graph2dot.c:48
unsigned char * buf_end
End of the data, may be less than buffer+buffer_size if the read function returned less data than req...
Definition: avio.h:85
int off
Definition: dsputil_bfin.c:29
uint64_t asf_pb_pos
cache for position of the asf demuxer, since we load a new data packet in the bytecontext for each in...
Definition: rtsp.h:310
AVIOContext * pktbuf
Definition: rtpdec_asf.c:159
unsigned int nb_streams
A list of all streams in the file.
Definition: avformat.h:1015
AVFormatContext * asf_ctx
The following are used for RTP/ASF streams.
Definition: rtsp.h:306
static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index, PayloadContext *asf, const char *line)
Definition: rtpdec_asf.c:130
ret
Definition: avfilter.c:961
AVStream ** streams
Definition: avformat.h:1016
static void init_packetizer(AVIOContext *pb, uint8_t *buf, int len)
Definition: rtpdec_asf.c:87
#define FFMIN(a, b)
Definition: avcodec.h:925
int ff_read_packet(AVFormatContext *s, AVPacket *pkt)
Read a transport packet from a media file.
Definition: utils.c:649
uint8_t ff_asf_guid[16]
Definition: riff.h:70
Stream structure.
Definition: avformat.h:667
const ff_asf_guid ff_asf_file_header
Definition: asf.c:27
#define RTP_FLAG_KEY
RTP packet contains a keyframe.
Definition: rtpdec.h:92
AVInputFormat ff_asf_demuxer
Definition: asfdec.c:1556
AVIOContext * pb
I/O context.
Definition: avformat.h:1001
void * buf
Definition: avisynth_c.h:594
int extradata_size
Definition: avcodec.h:1255
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:62
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1018
static void asfrtp_free_context(PayloadContext *asf)
Definition: rtpdec_asf.c:283
static PayloadContext * asfrtp_new_context(void)
Definition: rtpdec_asf.c:278
AVDictionary * metadata
Definition: avformat.h:1128
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:256
static int flags
Definition: cpu.c:45
#define AV_RL64(x)
Definition: intreadwrite.h:317
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:33
#define RTP_ASF_HANDLER(n, s, t)
Definition: rtpdec_asf.c:295
int ffio_init_context(AVIOContext *s, unsigned char *buffer, int buffer_size, int write_flag, void *opaque, int(*read_packet)(void *opaque, uint8_t *buf, int buf_size), int(*write_packet)(void *opaque, uint8_t *buf, int buf_size), int64_t(*seek)(void *opaque, int64_t offset, int whence))
Definition: aviobuf.c:71
AVFormatContext * avformat_alloc_context(void)
Allocate an AVFormatContext.
Definition: options.c:106
int64_t pos
position in the file of the current buffer
Definition: avio.h:94
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: utils.c:3309
int eof_reached
true if eof reached
Definition: avio.h:96
#define AV_RL32(x)
Definition: intreadwrite.h:275
int len
int av_base64_decode(uint8_t *out, const char *in, int out_size)
Decode a base64-encoded string.
Definition: base64.c:78
#define AVERROR(e)
static AVPacket pkt
Definition: demuxing.c:52
int stream_index
Definition: avcodec.h:1065
AVIOContext pb
Definition: rtpdec_asf.c:159
This structure stores compressed data.
Definition: avcodec.h:1040
void * av_mallocz(size_t size) av_malloc_attrib 1(1)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:241