<html> <head> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> <div class="moz-cite-prefix">Hello, I got this problem solved. I'm leaving this here for future visitors. Socket code that is working correctly (receiving multicast UDP when mobile data is turned on) is as follows: ---------- fd = socket(AF_INET, SOCK_DGRAM, 0); memset(&addr, 0, sizeof(addr)); addr.sin_len = sizeof(addr); addr.sin_family = AF_INET; addr.sin_addr.s_addr = INADDR_ANY; addr.sin_port = ntohs(5004); bind(fd, (const struct sockaddr *) &addr, sizeof(addr)) == 0; mreq.gr_interface = if_nametoindex(@"en0"); memset(&mreq.gr_group, 0, sizeof(mreq.gr_group)); a = (struct sockaddr_in *) &mreq.gr_group; a->sin_len = sizeof(addr); a->sin_family = AF_INET; a->sin_addr.s_addr = inet_addr("224.1.1.1"); a->sin_port = 0; setsockopt(fd, IPPROTO_IP, MCAST_JOIN_GROUP, &mreq, sizeof(mreq)) == 0; ---------- When I compare this with the socket creation code in Glib, I see a few differences: - <a class="moz-txt-link-freetext" href="https://github.com/GNOME/glib/blob/master/gio/gsocket.c#L2280">https://github.com/GNOME/glib/blob/master/gio/gsocket.c#L2280</a> => GlIb is using the group join operation IP_ADD_SOURCE_MEMBERSHIP, while the above code uses MCAST_JOIN_GROUP. - <a class="moz-txt-link-freetext" href="https://github.com/GNOME/glib/blob/master/gio/gsocket.c#L2236">https://github.com/GNOME/glib/blob/master/gio/gsocket.c#L2236</a> => GLib is only setting if_nametoindex (iface), but not mc_req.imr_interface.s_addr = g_htonl (INADDR_ANY), while in the above code: addr.sin_addr.s_addr = INADDR_ANY; and mreq.gr_interface = if_nametoindex (iface); The way I have solved this is by constructing the socket myself, similar to the example code provided, and to set the socket manually on the udpsrc element(s): ---------- gsocket_video = g_socket_new_from_fd(fd, &error); ... pipeline = gst_parse_launch(pipeline_desc, &error); ... GstElement* srcvideo = gst_bin_get_by_name((GstBin*)pipeline, "srcvideo"); g_object_set (srcvideo, "socket", gsocket_video, NULL); ---------- To answer this question: "Also is switching WWAN on causing a new interface to appear, or what effects does it have?" => There are no new interfaces, the list of real and virtual interfaces on iOS seem fixed. However, in my situation the WIFI is a LAN (so there is no internet access). I assume that when mobile data is turned on the default gateway of the system is changed in order to prefer traffic over WWAN. On 07/12/16 11:25, Sebastian Dröge wrote: </div> <blockquote cite="mid:1481106352.2416.153.camel@centricular.com" type="cite"> <pre wrap="">On Wed, 2016-12-07 at 01:17 +0100, Dries Langsweirdt wrote: </pre> <blockquote type="cite"> <pre wrap=""> I would like to know if I'm looking at an application specific problem or a general gstreamer problem, so if someone could confirm or de-confirm this behavior that would be great. Any suggestions as to how to proceed are greatly appreciated. </pre> </blockquote> <pre wrap=""> This would seem like a GStreamer or GLib problem. Can you compare what that other application does with the socket, and what udpsrc does different? Also is switching WWAN on causing a new interface to appear, or what effects does it have? </pre> <fieldset class="mimeAttachmentHeader"></fieldset> <pre wrap="">_______________________________________________ gstreamer-devel mailing list <a class="moz-txt-link-abbreviated" href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> <a class="moz-txt-link-freetext" href="https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel">https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a> </pre> </blockquote> <div class="moz-signature">-- Met vriendelijke groeten, Dries Langsweirdt Partner Flow Pilots M +32497729982 E <a class="moz-txt-link-abbreviated" href="mailto:dries.langsweirdt@flowpilots.com">dries.langsweirdt@flowpilots.com</a> W <a class="moz-txt-link-abbreviated" href="http://www.flowpilots.com">www.flowpilots.com</a> Please be informed that the Flow Pilots offices will be closed from Dec 26th 2016 until Jan 1st. 2017. </div> </body> </html>