2 * Session Announcement Protocol (RFC 2974) demuxer
3 * Copyright (c) 2010 Martin Storsjo
5 * This file is part of FFmpeg.
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.
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.
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
23 #include "libavutil/avassert.h"
24 #include "libavutil/avstring.h"
25 #include "libavutil/intreadwrite.h"
27 #include "os_support.h"
29 #include "avio_internal.h"
38 AVFormatContext *sdp_ctx;
45 static int sap_probe(AVProbeData *p)
47 if (av_strstart(p->filename, "sap:", NULL))
48 return AVPROBE_SCORE_MAX;
52 static int sap_read_close(AVFormatContext *s)
54 struct SAPState *sap = s->priv_data;
56 avformat_close_input(&sap->sdp_ctx);
58 ffurl_close(sap->ann_fd);
64 static int sap_read_header(AVFormatContext *s)
66 struct SAPState *sap = s->priv_data;
67 char host[1024], path[1024], url[1024];
68 uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
73 if (!ff_network_init())
76 av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
77 path, sizeof(path), s->filename);
82 /* Listen for announcements on sap.mcast.net if no host was specified */
83 av_strlcpy(host, "224.2.127.254", sizeof(host));
86 ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
88 ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ,
89 &s->interrupt_callback, NULL);
94 int addr_type, auth_len;
97 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
98 if (ret == AVERROR(EAGAIN))
102 recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
104 av_log(s, AV_LOG_WARNING, "Received too short packet\n");
108 if ((recvbuf[0] & 0xe0) != 0x20) {
109 av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
114 if (recvbuf[0] & 0x04) {
115 av_log(s, AV_LOG_WARNING, "Received stream deletion "
119 addr_type = recvbuf[0] & 0x10;
120 auth_len = recvbuf[1];
121 sap->hash = AV_RB16(&recvbuf[2]);
124 pos += 16; /* IPv6 */
128 if (pos + 4 >= ret) {
129 av_log(s, AV_LOG_WARNING, "Received too short packet\n");
132 #define MIME "application/sdp"
133 if (strcmp(&recvbuf[pos], MIME) == 0) {
134 pos += strlen(MIME) + 1;
135 } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
136 // Direct SDP without a mime type
138 av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
143 sap->sdp = av_strdup(&recvbuf[pos]);
147 av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
148 ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
151 infmt = av_find_input_format("sdp");
154 sap->sdp_ctx = avformat_alloc_context();
156 ret = AVERROR(ENOMEM);
159 sap->sdp_ctx->max_delay = s->max_delay;
160 sap->sdp_ctx->pb = &sap->sdp_pb;
161 sap->sdp_ctx->interrupt_callback = s->interrupt_callback;
163 if ((ret = ff_copy_whitelists(sap->sdp_ctx, s)) < 0)
166 ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
169 if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
170 s->ctx_flags |= AVFMTCTX_NOHEADER;
171 for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
172 AVStream *st = avformat_new_stream(s, NULL);
174 ret = AVERROR(ENOMEM);
178 avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
179 st->time_base = sap->sdp_ctx->streams[i]->time_base;
189 static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
191 struct SAPState *sap = s->priv_data;
192 int fd = ffurl_get_file_handle(sap->ann_fd);
194 struct pollfd p = {fd, POLLIN, 0};
195 uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
202 if (n <= 0 || !(p.revents & POLLIN))
204 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
206 uint16_t hash = AV_RB16(&recvbuf[2]);
207 /* Should ideally check the source IP address, too */
208 if (recvbuf[0] & 0x04 && hash == sap->hash) {
209 /* Stream deletion */
215 ret = av_read_frame(sap->sdp_ctx, pkt);
218 if (s->ctx_flags & AVFMTCTX_NOHEADER) {
219 while (sap->sdp_ctx->nb_streams > s->nb_streams) {
220 int i = s->nb_streams;
221 AVStream *st = avformat_new_stream(s, NULL);
224 return AVERROR(ENOMEM);
227 avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
228 st->time_base = sap->sdp_ctx->streams[i]->time_base;
234 AVInputFormat ff_sap_demuxer = {
236 .long_name = NULL_IF_CONFIG_SMALL("SAP input"),
237 .priv_data_size = sizeof(struct SAPState),
238 .read_probe = sap_probe,
239 .read_header = sap_read_header,
240 .read_packet = sap_fetch_packet,
241 .read_close = sap_read_close,
242 .flags = AVFMT_NOFILE,