Add a demuxer for receiving raw rtp:// URLs without an SDP description

The demuxer inspects the payload type of a received RTP packet and
handles the cases where the content is fully described by the payload type.

Originally committed as revision 25527 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 104 insertions, 0 deletions

diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
index 6570c38..aff745a 100644
--- a/libavformat/rtsp.c
+++ b/libavformat/rtsp.c
@@ -2104,3 +2104,107 @@ AVInputFormat sdp_demuxer = {
     rtsp_fetch_packet,
     sdp_read_close,
 };
+
+static int rtp_probe(AVProbeData *p)
+{
+    if (av_strstart(p->filename, "rtp:", NULL))
+        return AVPROBE_SCORE_MAX;
+    return 0;
+}
+
+static int rtp_read_header(AVFormatContext *s,
+                           AVFormatParameters *ap)
+{
+    uint8_t recvbuf[1500];
+    char host[500], sdp[500];
+    int ret, port;
+    URLContext* in = NULL;
+    int payload_type;
+    AVCodecContext codec;
+    struct sockaddr_storage addr;
+    ByteIOContext pb;
+    socklen_t addrlen = sizeof(addr);
+
+    if (!ff_network_init())
+        return AVERROR(EIO);
+
+    ret = url_open(&in, s->filename, URL_RDONLY);
+    if (ret)
+        goto fail;
+
+    while (1) {
+        ret = url_read(in, recvbuf, sizeof(recvbuf));
+        if (ret == AVERROR(EAGAIN))
+            continue;
+        if (ret < 0)
+            goto fail;
+        if (ret < 12) {
+            av_log(s, AV_LOG_WARNING, "Received too short packet\n");
+            continue;
+        }
+
+        if ((recvbuf[0] & 0xc0) != 0x80) {
+            av_log(s, AV_LOG_WARNING, "Unsupported RTP version packet "
+                                      "received\n");
+            continue;
+        }
+
+        payload_type = recvbuf[1] & 0x7f;
+        break;
+    }
+    getsockname(url_get_file_handle(in), (struct sockaddr*) &addr, &addrlen);
+    url_close(in);
+    in = NULL;
+
+    memset(&codec, 0, sizeof(codec));
+    if (ff_rtp_get_codec_info(&codec, payload_type)) {
+        av_log(s, AV_LOG_ERROR, "Unable to receive RTP payload type %d "
+                                "without an SDP file describing it\n",
+                                 payload_type);
+        goto fail;
+    }
+    if (codec.codec_type != AVMEDIA_TYPE_DATA) {
+        av_log(s, AV_LOG_WARNING, "Guessing on RTP content - if not received "
+                                  "properly you need an SDP file "
+                                  "describing it\n");
+    }
+
+    av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
+                 NULL, 0, s->filename);
+
+    snprintf(sdp, sizeof(sdp),
+             "v=0\r\nc=IN IP%d %s\r\nm=%s %d RTP/AVP %d\r\n",
+             addr.ss_family == AF_INET ? 4 : 6, host,
+             codec.codec_type == AVMEDIA_TYPE_DATA  ? "application" :
+             codec.codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio",
+             port, payload_type);
+    av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sdp);
+
+    init_put_byte(&pb, sdp, strlen(sdp), 0, NULL, NULL, NULL, NULL);
+    s->pb = &pb;
+
+    /* sdp_read_header initializes this again */
+    ff_network_close();
+
+    ret = sdp_read_header(s, ap);
+    s->pb = NULL;
+    return ret;
+
+fail:
+    if (in)
+        url_close(in);
+    ff_network_close();
+    return ret;
+}
+
+AVInputFormat rtp_demuxer = {
+    "rtp",
+    NULL_IF_CONFIG_SMALL("RTP input format"),
+    sizeof(RTSPState),
+    rtp_probe,
+    rtp_read_header,
+    rtsp_fetch_packet,
+    sdp_read_close,
+    .flags = AVFMT_NOFILE,
+};
+