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GStreamer Good Plugins 0.10 Plugins Reference Manual | |
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| Top | Description | Object Hierarchy | Implemented Interfaces | Properties | ||||
GObject
+----GstObject
+----GstElement
+----GstBaseSrc
+----GstPushSrc
+----GstUDPSrc
"caps" GstCaps* : Read / Write "multicast-group" gchar* : Read / Write "port" gint : Read / Write "uri" gchar* : Read / Write "sockfd" gint : Read / Write "buffer-size" gint : Read / Write "timeout" guint64 : Read / Write "closefd" gboolean : Read / Write "skip-first-bytes" gint : Read / Write "sock" gint : Read "auto-multicast" gboolean : Read / Write "multicast-iface" gchar* : Read / Write
udpsrc is a network source that reads UDP packets from the network. It can be combined with RTP depayloaders to implement RTP streaming.
The udpsrc element supports automatic port allocation by setting the "port" property to 0. After setting the udpsrc to PAUSED, the allocated port can be obtained by reading the port property.
udpsrc can read from multicast groups by setting the "multicast-group" property to the IP address of the multicast group.
Alternatively one can provide a custom socket to udpsrc with the "sockfd" property, udpsrc will then not allocate a socket itself but use the provided one.
The "caps" property is mainly used to give a type to the UDP packet so that they can be autoplugged in GStreamer pipelines. This is very usefull for RTP implementations where the contents of the UDP packets is transfered out-of-bounds using SDP or other means.
The "buffer" property is used to change the default kernel buffer sizes used for receiving packets. The buffer size may be increased for high-volume connections, or may be decreased to limit the possible backlog of incoming data. The system places an absolute limit on these values, on Linux, for example, the default buffer size is typically 50K and can be increased to maximally 100K.
The "skip-first-bytes" property is used to strip off an arbitrary number of bytes from the start of the raw udp packet and can be used to strip off proprietary header, for example.
The udpsrc is always a live source. It does however not provide a GstClock, this is left for upstream elements such as an RTP session manager or demuxer (such as an MPEG demuxer). As with all live sources, the captured buffers will have their timestamp set to the current running time of the pipeline.
udpsrc implements a GstURIHandler interface that handles udp://host:port type URIs.
If the "timeout" property is set to a value bigger than 0, udpsrc
will generate an element message named
"GstUDPSrcTimeout"
if no data was recieved in the given timeout.
The message's structure contains one field:
guint64
"timeout": the timeout in microseconds that
expired when waiting for data.
The message is typically used to detect that no UDP arrives in the receiver because it is blocked by a firewall.
A custom file descriptor can be configured with the "sockfd" property. The socket will be closed when setting the element to READY by default. This behaviour can be overriden with the "closefd" property, in which case the application is responsible for closing the file descriptor.
gst-launch -v udpsrc ! fakesink dump=1
gst-launch -v audiotestsrc ! udpsink
gst-launch -v udpsrc port=0 ! fakesink
Last reviewed on 2007-09-20 (0.10.7)
"multicast-group" property "multicast-group" gchar* : Read / Write
The Address of multicast group to join.
Default value: "0.0.0.0"
"port" property "port" gint : Read / Write
The port to receive the packets from, 0=allocate.
Allowed values: [0,65535]
Default value: 4951
"uri" property "uri" gchar* : Read / Write
URI in the form of udp://multicast_group:port.
Default value: "udp://0.0.0.0:4951"
"sockfd" property "sockfd" gint : Read / Write
Socket to use for UDP reception. (-1 == allocate).
Allowed values: >= G_MAXULONG
Default value: -1
"buffer-size" property "buffer-size" gint : Read / Write
Size of the kernel receive buffer in bytes, 0=default.
Allowed values: >= 0
Default value: 0
"timeout" property "timeout" guint64 : Read / Write
Post a message after timeout microseconds (0 = disabled).
Default value: 0
"closefd" property "closefd" gboolean : Read / Write
Close sockfd if passed as property on state change.
Default value: TRUE
"skip-first-bytes" property "skip-first-bytes" gint : Read / Write
number of bytes to skip for each udp packet.
Allowed values: >= 0
Default value: 0
"sock" property "sock" gint : Read
Socket currently in use for UDP reception. (-1 = no socket).
Allowed values: >= G_MAXULONG
Default value: -1
"auto-multicast" property "auto-multicast" gboolean : Read / Write
Automatically join/leave multicast groups.
Default value: TRUE