2 * Session Announcement Protocol (RFC 2974) demuxer
3 * Copyright (c) 2010 Martin Storsjo
5 * This file is part of Libav.
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.
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.
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
23 #include "libavutil/avstring.h"
24 #include "libavutil/intreadwrite.h"
26 #include "os_support.h"
28 #include "avio_internal.h"
37 AVFormatContext *sdp_ctx;
43 const URLProtocol **protocols;
46 static int sap_probe(AVProbeData *p)
48 if (av_strstart(p->filename, "sap:", NULL))
49 return AVPROBE_SCORE_MAX;
53 static int sap_read_close(AVFormatContext *s)
55 struct SAPState *sap = s->priv_data;
57 avformat_close_input(&sap->sdp_ctx);
59 ffurl_close(sap->ann_fd);
60 av_freep(&sap->protocols);
66 static int sap_read_header(AVFormatContext *s)
68 struct SAPState *sap = s->priv_data;
69 char host[1024], path[1024], url[1024];
70 uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
75 if (!ff_network_init())
78 av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
79 path, sizeof(path), s->filename);
84 /* Listen for announcements on sap.mcast.net if no host was specified */
85 av_strlcpy(host, "224.2.127.254", sizeof(host));
88 sap->protocols = ffurl_get_protocols(s->protocol_whitelist,
89 s->protocol_blacklist);
90 if (!sap->protocols) {
91 ret = AVERROR(ENOMEM);
95 ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
97 ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ,
98 &s->interrupt_callback, NULL, sap->protocols, NULL);
103 int addr_type, auth_len;
106 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
107 if (ret == AVERROR(EAGAIN))
111 recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
113 av_log(s, AV_LOG_WARNING, "Received too short packet\n");
117 if ((recvbuf[0] & 0xe0) != 0x20) {
118 av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
123 if (recvbuf[0] & 0x04) {
124 av_log(s, AV_LOG_WARNING, "Received stream deletion "
128 addr_type = recvbuf[0] & 0x10;
129 auth_len = recvbuf[1];
130 sap->hash = AV_RB16(&recvbuf[2]);
133 pos += 16; /* IPv6 */
137 if (pos + 4 >= ret) {
138 av_log(s, AV_LOG_WARNING, "Received too short packet\n");
141 #define MIME "application/sdp"
142 if (strcmp(&recvbuf[pos], MIME) == 0) {
143 pos += strlen(MIME) + 1;
144 } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
145 // Direct SDP without a mime type
147 av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
152 sap->sdp = av_strdup(&recvbuf[pos]);
156 av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
157 ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
160 infmt = av_find_input_format("sdp");
163 sap->sdp_ctx = avformat_alloc_context();
165 ret = AVERROR(ENOMEM);
168 sap->sdp_ctx->max_delay = s->max_delay;
169 sap->sdp_ctx->pb = &sap->sdp_pb;
170 sap->sdp_ctx->interrupt_callback = s->interrupt_callback;
171 ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
174 if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
175 s->ctx_flags |= AVFMTCTX_NOHEADER;
176 for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
177 AVStream *st = avformat_new_stream(s, NULL);
179 ret = AVERROR(ENOMEM);
183 avcodec_parameters_copy(st->codecpar, sap->sdp_ctx->streams[i]->codecpar);
184 st->time_base = sap->sdp_ctx->streams[i]->time_base;
194 static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
196 struct SAPState *sap = s->priv_data;
197 int fd = ffurl_get_file_handle(sap->ann_fd);
199 struct pollfd p = {fd, POLLIN, 0};
200 uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
207 if (n <= 0 || !(p.revents & POLLIN))
209 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
211 uint16_t hash = AV_RB16(&recvbuf[2]);
212 /* Should ideally check the source IP address, too */
213 if (recvbuf[0] & 0x04 && hash == sap->hash) {
214 /* Stream deletion */
220 ret = av_read_frame(sap->sdp_ctx, pkt);
223 if (s->ctx_flags & AVFMTCTX_NOHEADER) {
224 while (sap->sdp_ctx->nb_streams > s->nb_streams) {
225 int i = s->nb_streams;
226 AVStream *st = avformat_new_stream(s, NULL);
228 av_packet_unref(pkt);
229 return AVERROR(ENOMEM);
232 avcodec_parameters_copy(st->codecpar, sap->sdp_ctx->streams[i]->codecpar);
233 st->time_base = sap->sdp_ctx->streams[i]->time_base;
239 AVInputFormat ff_sap_demuxer = {
241 .long_name = NULL_IF_CONFIG_SMALL("SAP input"),
242 .priv_data_size = sizeof(struct SAPState),
243 .read_probe = sap_probe,
244 .read_header = sap_read_header,
245 .read_packet = sap_fetch_packet,
246 .read_close = sap_read_close,
247 .flags = AVFMT_NOFILE,