udpsrc

udpsrc — Receive data over the network via UDP

Synopsis

struct              GstUDPSrc;

Object Hierarchy

  GObject
   +----GInitiallyUnowned
         +----GstObject
               +----GstElement
                     +----GstBaseSrc
                           +----GstPushSrc
                                 +----GstUDPSrc

Implemented Interfaces

GstUDPSrc implements GstURIHandler.

Properties

  "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
  "reuse"                    gboolean              : Read / Write
  "close-socket"             gboolean              : Read / Write
  "socket"                   GSocket*              : Read / Write
  "used-socket"              GSocket*              : Read
  "bind-address"             gchar*                : Read / Write
  "address"                  gchar*                : Read / Write

Description

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-size" property is used to change the default kernel buffersizes 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.

Examples

1
gst-launch-1.0 -v udpsrc ! fakesink dump=1
A pipeline to read from the default port and dump the udp packets. To actually generate udp packets on the default port one can use the udpsink element. When running the following pipeline in another terminal, the above mentioned pipeline should dump data packets to the console.
1
gst-launch-1.0 -v audiotestsrc ! udpsink
1
gst-launch-1.0 -v udpsrc port=0 ! fakesink
read udp packets from a free port.

Last reviewed on 2007-09-20 (0.10.7)

Synopsis

Element Information

plugin

udp

author

Wim Taymans <wim@fluendo.com>, Thijs Vermeir <thijs.vermeir@barco.com>

class

Source/Network

Element Pads

name

src

direction

source

presence

always

details

ANY

Details

struct GstUDPSrc

struct GstUDPSrc;

Property Details

The "caps" property

  "caps"                     GstCaps*              : Read / Write

The caps of the source pad.


The "multicast-group" property

  "multicast-group"          gchar*                : Read / Write

The Address of multicast group to join. DEPRECATED: Use address property instead.

Default value: "0.0.0.0"


The "port" property

  "port"                     gint                  : Read / Write

The port to receive the packets from, 0=allocate.

Allowed values: [0,65535]

Default value: 5004


The "uri" property

  "uri"                      gchar*                : Read / Write

URI in the form of udp://multicast_group:port.

Default value: "udp://0.0.0.0:5004"


The "sockfd" property

  "sockfd"                   gint                  : Read / Write

Socket to use for UDP reception. (-1 == allocate).

Allowed values: >= G_MAXULONG

Default value: -1


The "buffer-size" property

  "buffer-size"              gint                  : Read / Write

Size of the kernel receive buffer in bytes, 0=default.

Allowed values: >= 0

Default value: 0


The "timeout" property

  "timeout"                  guint64               : Read / Write

Post a message after timeout nanoseconds (0 = disabled).

Default value: 0


The "closefd" property

  "closefd"                  gboolean              : Read / Write

Close sockfd if passed as property on state change.

Default value: TRUE


The "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


The "sock" property

  "sock"                     gint                  : Read

Socket currently in use for UDP reception. (-1 = no socket).

Allowed values: >= G_MAXULONG

Default value: -1


The "auto-multicast" property

  "auto-multicast"           gboolean              : Read / Write

Automatically join/leave multicast groups.

Default value: TRUE


The "multicast-iface" property

  "multicast-iface"          gchar*                : Read / Write

The network interface on which to join the multicast group.

Default value: NULL


The "reuse" property

  "reuse"                    gboolean              : Read / Write

Enable reuse of the port.

Default value: TRUE


The "close-socket" property

  "close-socket"             gboolean              : Read / Write

Close socket if passed as property on state change.

Default value: TRUE


The "socket" property

  "socket"                   GSocket*              : Read / Write

Socket to use for UDP reception. (NULL == allocate).


The "used-socket" property

  "used-socket"              GSocket*              : Read

Socket currently in use for UDP reception. (NULL = no socket).


The "bind-address" property

  "bind-address"             gchar*                : Read / Write

Address to bind the socket to. This is equivalent to the multicast-group property.

Default value: "0.0.0.0"


The "address" property

  "address"                  gchar*                : Read / Write

Address to receive packets for. This is equivalent to the multicast-group property for now.

Default value: "0.0.0.0"

See Also

udpsink, multifdsink