sapdec.c
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1 /*
2  * Session Announcement Protocol (RFC 2974) demuxer
3  * Copyright (c) 2010 Martin Storsjo
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 #include "avformat.h"
23 #include "libavutil/avstring.h"
24 #include "libavutil/intreadwrite.h"
25 #include "network.h"
26 #include "os_support.h"
27 #include "internal.h"
28 #include "avio_internal.h"
29 #include "url.h"
30 #include "rtpdec.h"
31 #if HAVE_POLL_H
32 #include <poll.h>
33 #endif
34 
35 struct SAPState {
36  URLContext *ann_fd;
37  AVFormatContext *sdp_ctx;
38  AVIOContext sdp_pb;
39  uint16_t hash;
40  char *sdp;
41  int eof;
42 };
43 
44 static int sap_probe(AVProbeData *p)
45 {
46  if (av_strstart(p->filename, "sap:", NULL))
47  return AVPROBE_SCORE_MAX;
48  return 0;
49 }
50 
51 static int sap_read_close(AVFormatContext *s)
52 {
53  struct SAPState *sap = s->priv_data;
54  if (sap->sdp_ctx)
55  avformat_close_input(&sap->sdp_ctx);
56  if (sap->ann_fd)
57  ffurl_close(sap->ann_fd);
58  av_freep(&sap->sdp);
59  ff_network_close();
60  return 0;
61 }
62 
63 static int sap_read_header(AVFormatContext *s)
64 {
65  struct SAPState *sap = s->priv_data;
66  char host[1024], path[1024], url[1024];
67  uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
68  int port;
69  int ret, i;
70  AVInputFormat* infmt;
71 
72  if (!ff_network_init())
73  return AVERROR(EIO);
74 
75  av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
76  path, sizeof(path), s->filename);
77  if (port < 0)
78  port = 9875;
79 
80  if (!host[0]) {
81  /* Listen for announcements on sap.mcast.net if no host was specified */
82  av_strlcpy(host, "224.2.127.254", sizeof(host));
83  }
84 
85  ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
86  port);
87  ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ,
88  &s->interrupt_callback, NULL);
89  if (ret)
90  goto fail;
91 
92  while (1) {
93  int addr_type, auth_len;
94  int pos;
95 
96  ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
97  if (ret == AVERROR(EAGAIN))
98  continue;
99  if (ret < 0)
100  goto fail;
101  recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
102  if (ret < 8) {
103  av_log(s, AV_LOG_WARNING, "Received too short packet\n");
104  continue;
105  }
106 
107  if ((recvbuf[0] & 0xe0) != 0x20) {
108  av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
109  "received\n");
110  continue;
111  }
112 
113  if (recvbuf[0] & 0x04) {
114  av_log(s, AV_LOG_WARNING, "Received stream deletion "
115  "announcement\n");
116  continue;
117  }
118  addr_type = recvbuf[0] & 0x10;
119  auth_len = recvbuf[1];
120  sap->hash = AV_RB16(&recvbuf[2]);
121  pos = 4;
122  if (addr_type)
123  pos += 16; /* IPv6 */
124  else
125  pos += 4; /* IPv4 */
126  pos += auth_len * 4;
127  if (pos + 4 >= ret) {
128  av_log(s, AV_LOG_WARNING, "Received too short packet\n");
129  continue;
130  }
131 #define MIME "application/sdp"
132  if (strcmp(&recvbuf[pos], MIME) == 0) {
133  pos += strlen(MIME) + 1;
134  } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
135  // Direct SDP without a mime type
136  } else {
137  av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
138  &recvbuf[pos]);
139  continue;
140  }
141 
142  sap->sdp = av_strdup(&recvbuf[pos]);
143  break;
144  }
145 
146  av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
147  ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
148  NULL, NULL);
149 
150  infmt = av_find_input_format("sdp");
151  if (!infmt)
152  goto fail;
153  sap->sdp_ctx = avformat_alloc_context();
154  if (!sap->sdp_ctx) {
155  ret = AVERROR(ENOMEM);
156  goto fail;
157  }
158  sap->sdp_ctx->max_delay = s->max_delay;
159  sap->sdp_ctx->pb = &sap->sdp_pb;
160  sap->sdp_ctx->interrupt_callback = s->interrupt_callback;
161  ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
162  if (ret < 0)
163  goto fail;
164  if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
165  s->ctx_flags |= AVFMTCTX_NOHEADER;
166  for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
167  AVStream *st = avformat_new_stream(s, NULL);
168  if (!st) {
169  ret = AVERROR(ENOMEM);
170  goto fail;
171  }
172  st->id = i;
173  avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
174  st->time_base = sap->sdp_ctx->streams[i]->time_base;
175  }
176 
177  return 0;
178 
179 fail:
180  sap_read_close(s);
181  return ret;
182 }
183 
184 static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
185 {
186  struct SAPState *sap = s->priv_data;
187  int fd = ffurl_get_file_handle(sap->ann_fd);
188  int n, ret;
189  struct pollfd p = {fd, POLLIN, 0};
190  uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
191 
192  if (sap->eof)
193  return AVERROR_EOF;
194 
195  while (1) {
196  n = poll(&p, 1, 0);
197  if (n <= 0 || !(p.revents & POLLIN))
198  break;
199  ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
200  if (ret >= 8) {
201  uint16_t hash = AV_RB16(&recvbuf[2]);
202  /* Should ideally check the source IP address, too */
203  if (recvbuf[0] & 0x04 && hash == sap->hash) {
204  /* Stream deletion */
205  sap->eof = 1;
206  return AVERROR_EOF;
207  }
208  }
209  }
210  ret = av_read_frame(sap->sdp_ctx, pkt);
211  if (ret < 0)
212  return ret;
213  if (s->ctx_flags & AVFMTCTX_NOHEADER) {
214  while (sap->sdp_ctx->nb_streams > s->nb_streams) {
215  int i = s->nb_streams;
216  AVStream *st = avformat_new_stream(s, NULL);
217  if (!st) {
218  av_free_packet(pkt);
219  return AVERROR(ENOMEM);
220  }
221  st->id = i;
222  avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
223  st->time_base = sap->sdp_ctx->streams[i]->time_base;
224  }
225  }
226  return ret;
227 }
228 
229 AVInputFormat ff_sap_demuxer = {
230  .name = "sap",
231  .long_name = NULL_IF_CONFIG_SMALL("SAP input"),
232  .priv_data_size = sizeof(struct SAPState),
233  .read_probe = sap_probe,
234  .read_header = sap_read_header,
235  .read_packet = sap_fetch_packet,
236  .read_close = sap_read_close,
237  .flags = AVFMT_NOFILE,
238 };
av_url_split
void av_url_split(char *proto, int proto_size, char *authorization, int authorization_size, char *hostname, int hostname_size, int *port_ptr, char *path, int path_size, const char *url)
Split a URL string into components.
Definition: libavformat/utils.c:3830
sap_read_close
static int sap_read_close(AVFormatContext *s)
Definition: sapdec.c:51
s
const char * s
Definition: avisynth_c.h:668
AVIOContext
Bytestream IO Context.
Definition: avio.h:68
av_free_packet
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:242
RTP_MAX_PACKET_LENGTH
#define RTP_MAX_PACKET_LENGTH
Definition: rtpdec.h:36
AVFormatContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1125
AVProbeData::filename
const char * filename
Definition: avformat.h:335
avformat_open_input
int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: libavformat/utils.c:614
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:154
ff_sap_demuxer
AVInputFormat ff_sap_demuxer
Definition: sapdec.c:229
AVIO_FLAG_READ
#define AVIO_FLAG_READ
read-only
Definition: avio.h:332
ff_network_close
void ff_network_close(void)
Definition: network.c:173
SAPState::sdp_pb
AVIOContext sdp_pb
Definition: sapdec.c:38
AVFormatContext::ctx_flags
int ctx_flags
Format-specific flags, see AVFMTCTX_xx.
Definition: avformat.h:980
avcodec_copy_context
int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src)
Copy the settings of the source AVCodecContext into the destination AVCodecContext.
Definition: libavcodec/options.c:182
ff_url_join
int ff_url_join(char *str, int size, const char *proto, const char *authorization, const char *hostname, int port, const char *fmt,...) av_printf_format(7
Assemble a URL string from components.
av_freep
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:198
AVFormatContext
Format I/O context.
Definition: avformat.h:944
uint8_t
uint8_t
Definition: audio_convert.c:194
ff_network_init
int ff_network_init(void)
Definition: network.c:126
AVFMTCTX_NOHEADER
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:914
os_support.h
miscellaneous OS support macros and functions.
pkt
static AVPacket pkt
Definition: demuxing.c:56
AVStream::id
int id
Format-specific stream ID.
Definition: avformat.h:650
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: libavformat/utils.c:3362
AVFormatContext::streams
AVStream ** streams
Definition: avformat.h:992
avformat_alloc_context
AVFormatContext * avformat_alloc_context(void)
Allocate an AVFormatContext.
Definition: libavformat/options.c:106
avio_internal.h
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
SAPState::hash
uint16_t hash
Definition: sapdec.c:39
sap_fetch_packet
static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
Definition: sapdec.c:184
AV_RB16
#define AV_RB16
Definition: avr32/intreadwrite.h:53
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: libavutil/internal.h:123
av_log
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:246
av_strlcpy
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:82
AVStream::codec
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:662
AVFormatContext::nb_streams
unsigned int nb_streams
A list of all streams in the file.
Definition: avformat.h:991
AV_LOG_VERBOSE
#define AV_LOG_VERBOSE
Definition: log.h:157
av_find_input_format
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: libavformat/utils.c:248
AVFormatContext::filename
char filename[1024]
input or output filename
Definition: avformat.h:994
SAPState::ann_fd
URLContext * ann_fd
Definition: sapdec.c:36
ret
ret
Definition: avfilter.c:821
SAPState::sdp_ctx
AVFormatContext * sdp_ctx
Definition: sapdec.c:37
ffurl_get_file_handle
int ffurl_get_file_handle(URLContext *h)
Return the file descriptor associated with this URL.
Definition: avio.c:399
SAPState::sdp
char * sdp
Definition: sapdec.c:40
AVStream
Stream structure.
Definition: avformat.h:643
NULL
NULL
Definition: eval.c:55
av_strdup
char * av_strdup(const char *s)
Duplicate the string s.
Definition: mem.c:220
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:977
URLContext
Definition: url.h:41
i
synthesis window for stochastic i
Definition: code Kat/hpsmodel.m:34
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:334
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFilterBuffer structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Buffer references ownership and permissions
av_read_frame
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: libavformat/utils.c:1530
sap_read_header
static int sap_read_header(AVFormatContext *s)
Definition: sapdec.c:63
sap_probe
static int sap_probe(AVProbeData *p)
Definition: sapdec.c:44
ffurl_close
int ffurl_close(URLContext *h)
Definition: avio.c:359
n
n
Definition: genspecsines_sin.m:10
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score, half of that is used for file-extension-based detection
Definition: avformat.h:340
av_strstart
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
avformat.h
Main libavformat public API header.
MIME
#define MIME
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:345
ffio_init_context
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
ffurl_open
int ffurl_open(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Create an URLContext for accessing to the resource indicated by url, and open it. ...
Definition: avio.c:247
avformat_close_input
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: libavformat/utils.c:3329
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:964
SAPState::eof
int eof
Definition: sapdec.c:41
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:461
url.h
unbuffered private I/O API
AVStream::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:679
AVPacket
This structure stores compressed data.
Definition: libavcodec/avcodec.h:1028
ffurl_read
int ffurl_read(URLContext *h, unsigned char *buf, int size)
Read up to size bytes from the resource accessed by h, and store the read bytes in buf...
Definition: avio.c:303
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