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1 /*
2  * RTSP muxer
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 
24 #if HAVE_POLL_H
25 #include <poll.h>
26 #endif
27 #include "network.h"
28 #include "os_support.h"
29 #include "rtsp.h"
30 #include "internal.h"
31 #include "avio_internal.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/avstring.h"
34 #include "libavutil/time.h"
35 #include "url.h"
36 
37 
38 static const AVClass rtsp_muxer_class = {
39     .class_name = "RTSP muxer",
40     .item_name  = av_default_item_name,
41     .option     = ff_rtsp_options,
42     .version    = LIBAVUTIL_VERSION_INT,
43 };
44 
ff_rtsp_setup_output_streams(AVFormatContext * s,const char * addr)45 int ff_rtsp_setup_output_streams(AVFormatContext *s, const char *addr)
46 {
47     RTSPState *rt = s->priv_data;
48     RTSPMessageHeader reply1, *reply = &reply1;
49     int i;
50     char *sdp;
51     AVFormatContext sdp_ctx, *ctx_array[1];
52     char url[MAX_URL_SIZE];
53 
54     if (s->start_time_realtime == 0  ||  s->start_time_realtime == AV_NOPTS_VALUE)
55         s->start_time_realtime = av_gettime();
56 
57     /* Announce the stream */
58     sdp = av_mallocz(SDP_MAX_SIZE);
59     if (!sdp)
60         return AVERROR(ENOMEM);
61     /* We create the SDP based on the RTSP AVFormatContext where we
62      * aren't allowed to change the filename field. (We create the SDP
63      * based on the RTSP context since the contexts for the RTP streams
64      * don't exist yet.) In order to specify a custom URL with the actual
65      * peer IP instead of the originally specified hostname, we create
66      * a temporary copy of the AVFormatContext, where the custom URL is set.
67      *
68      * FIXME: Create the SDP without copying the AVFormatContext.
69      * This either requires setting up the RTP stream AVFormatContexts
70      * already here (complicating things immensely) or getting a more
71      * flexible SDP creation interface.
72      */
73     sdp_ctx = *s;
74     sdp_ctx.url = url;
75     ff_url_join(url, sizeof(url),
76                 "rtsp", NULL, addr, -1, NULL);
77     ctx_array[0] = &sdp_ctx;
78     if (av_sdp_create(ctx_array, 1, sdp, SDP_MAX_SIZE)) {
79         av_free(sdp);
80         return AVERROR_INVALIDDATA;
81     }
82     av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sdp);
83     ff_rtsp_send_cmd_with_content(s, "ANNOUNCE", rt->control_uri,
84                                   "Content-Type: application/sdp\r\n",
85                                   reply, NULL, sdp, strlen(sdp));
86     av_free(sdp);
87     if (reply->status_code != RTSP_STATUS_OK)
88         return ff_rtsp_averror(reply->status_code, AVERROR_INVALIDDATA);
89 
90     /* Set up the RTSPStreams for each AVStream */
91     for (i = 0; i < s->nb_streams; i++) {
92         RTSPStream *rtsp_st;
93 
94         rtsp_st = av_mallocz(sizeof(RTSPStream));
95         if (!rtsp_st)
96             return AVERROR(ENOMEM);
97         dynarray_add(&rt->rtsp_streams, &rt->nb_rtsp_streams, rtsp_st);
98 
99         rtsp_st->stream_index = i;
100 
101         av_strlcpy(rtsp_st->control_url, rt->control_uri, sizeof(rtsp_st->control_url));
102         /* Note, this must match the relative uri set in the sdp content */
103         av_strlcatf(rtsp_st->control_url, sizeof(rtsp_st->control_url),
104                     "/streamid=%d", i);
105     }
106 
107     return 0;
108 }
109 
rtsp_write_record(AVFormatContext * s)110 static int rtsp_write_record(AVFormatContext *s)
111 {
112     RTSPState *rt = s->priv_data;
113     RTSPMessageHeader reply1, *reply = &reply1;
114     char cmd[MAX_URL_SIZE];
115 
116     snprintf(cmd, sizeof(cmd),
117              "Range: npt=0.000-\r\n");
118     ff_rtsp_send_cmd(s, "RECORD", rt->control_uri, cmd, reply, NULL);
119     if (reply->status_code != RTSP_STATUS_OK)
120         return ff_rtsp_averror(reply->status_code, -1);
121     rt->state = RTSP_STATE_STREAMING;
122     return 0;
123 }
124 
rtsp_write_header(AVFormatContext * s)125 static int rtsp_write_header(AVFormatContext *s)
126 {
127     int ret;
128 
129     ret = ff_rtsp_connect(s);
130     if (ret)
131         return ret;
132 
133     if (rtsp_write_record(s) < 0) {
134         ff_rtsp_close_streams(s);
135         ff_rtsp_close_connections(s);
136         return AVERROR_INVALIDDATA;
137     }
138     return 0;
139 }
140 
ff_rtsp_tcp_write_packet(AVFormatContext * s,RTSPStream * rtsp_st)141 int ff_rtsp_tcp_write_packet(AVFormatContext *s, RTSPStream *rtsp_st)
142 {
143     RTSPState *rt = s->priv_data;
144     AVFormatContext *rtpctx = rtsp_st->transport_priv;
145     uint8_t *buf, *ptr;
146     int size;
147     uint8_t *interleave_header, *interleaved_packet;
148 
149     size = avio_close_dyn_buf(rtpctx->pb, &buf);
150     rtpctx->pb = NULL;
151     ptr = buf;
152     while (size > 4) {
153         uint32_t packet_len = AV_RB32(ptr);
154         int id;
155         /* The interleaving header is exactly 4 bytes, which happens to be
156          * the same size as the packet length header from
157          * ffio_open_dyn_packet_buf. So by writing the interleaving header
158          * over these bytes, we get a consecutive interleaved packet
159          * that can be written in one call. */
160         interleaved_packet = interleave_header = ptr;
161         ptr += 4;
162         size -= 4;
163         if (packet_len > size || packet_len < 2)
164             break;
165         if (RTP_PT_IS_RTCP(ptr[1]))
166             id = rtsp_st->interleaved_max; /* RTCP */
167         else
168             id = rtsp_st->interleaved_min; /* RTP */
169         interleave_header[0] = '$';
170         interleave_header[1] = id;
171         AV_WB16(interleave_header + 2, packet_len);
172         ffurl_write(rt->rtsp_hd_out, interleaved_packet, 4 + packet_len);
173         ptr += packet_len;
174         size -= packet_len;
175     }
176     av_free(buf);
177     return ffio_open_dyn_packet_buf(&rtpctx->pb, RTSP_TCP_MAX_PACKET_SIZE);
178 }
179 
rtsp_write_packet(AVFormatContext * s,AVPacket * pkt)180 static int rtsp_write_packet(AVFormatContext *s, AVPacket *pkt)
181 {
182     RTSPState *rt = s->priv_data;
183     RTSPStream *rtsp_st;
184     int n;
185     struct pollfd p = {ffurl_get_file_handle(rt->rtsp_hd), POLLIN, 0};
186     AVFormatContext *rtpctx;
187     int ret;
188 
189     while (1) {
190         n = poll(&p, 1, 0);
191         if (n <= 0)
192             break;
193         if (p.revents & POLLIN) {
194             RTSPMessageHeader reply;
195 
196             /* Don't let ff_rtsp_read_reply handle interleaved packets,
197              * since it would block and wait for an RTSP reply on the socket
198              * (which may not be coming any time soon) if it handles
199              * interleaved packets internally. */
200             ret = ff_rtsp_read_reply(s, &reply, NULL, 1, NULL);
201             if (ret < 0)
202                 return AVERROR(EPIPE);
203             if (ret == 1)
204                 ff_rtsp_skip_packet(s);
205             /* XXX: parse message */
206             if (rt->state != RTSP_STATE_STREAMING)
207                 return AVERROR(EPIPE);
208         }
209     }
210 
211     if (pkt->stream_index < 0 || pkt->stream_index >= rt->nb_rtsp_streams)
212         return AVERROR_INVALIDDATA;
213     rtsp_st = rt->rtsp_streams[pkt->stream_index];
214     rtpctx = rtsp_st->transport_priv;
215 
216     ret = ff_write_chained(rtpctx, 0, pkt, s, 0);
217     /* ff_write_chained does all the RTP packetization. If using TCP as
218      * transport, rtpctx->pb is only a dyn_packet_buf that queues up the
219      * packets, so we need to send them out on the TCP connection separately.
220      */
221     if (!ret && rt->lower_transport == RTSP_LOWER_TRANSPORT_TCP)
222         ret = ff_rtsp_tcp_write_packet(s, rtsp_st);
223     return ret;
224 }
225 
rtsp_write_close(AVFormatContext * s)226 static int rtsp_write_close(AVFormatContext *s)
227 {
228     RTSPState *rt = s->priv_data;
229 
230     // If we want to send RTCP_BYE packets, these are sent by av_write_trailer.
231     // Thus call this on all streams before doing the teardown. This is
232     // done within ff_rtsp_undo_setup.
233     ff_rtsp_undo_setup(s, 1);
234 
235     ff_rtsp_send_cmd_async(s, "TEARDOWN", rt->control_uri, NULL);
236 
237     ff_rtsp_close_streams(s);
238     ff_rtsp_close_connections(s);
239     ff_network_close();
240     return 0;
241 }
242 
243 AVOutputFormat ff_rtsp_muxer = {
244     .name              = "rtsp",
245     .long_name         = NULL_IF_CONFIG_SMALL("RTSP output"),
246     .priv_data_size    = sizeof(RTSPState),
247     .audio_codec       = AV_CODEC_ID_AAC,
248     .video_codec       = AV_CODEC_ID_MPEG4,
249     .write_header      = rtsp_write_header,
250     .write_packet      = rtsp_write_packet,
251     .write_trailer     = rtsp_write_close,
252     .flags             = AVFMT_NOFILE | AVFMT_GLOBALHEADER,
253     .priv_class        = &rtsp_muxer_class,
254 };
255