Class: RTP::Receiver

Inherits:
Object
  • Object
show all
Includes:
LogSwitch::Mixin
Defined in:
lib/rtp/receiver.rb

Overview

Objects of this type receive RTP data over a socket and either save them to a file, or yield the packets to a given block. This is useful with other protocols, like RTSP.

Constant Summary collapse

DEFAULT_CAPFILE_NAME =

Name of the file the data will be captured to unless #rtp_file is set.

"rtp_capture.raw"
MAX_BYTES_TO_RECEIVE =

Maximum number of bytes to receive on the socket.

1500
MULTICAST_TTL =

TTL value that will be used if receiving on a multicast socket.

4

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Receiver

Returns a new instance of Receiver.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :rtp_port (Fixnum) —

    The port on which to capture RTP data. rtcp_port will be set to the next port above this.

  • :transport_protocol (Symbol) —

    The type of socket to use for capturing the data. :UDP or :TCP.

  • :ip_address (String) —

    The IP address to open the socket on. If this is a multicast address, multicast options will be set.

  • :strip_headers (Boolean) —

    If set to true, RTP headers will be stripped from packets before they’re written to the capture file.

  • :capture_file (File) —

    The file object to capture the RTP data to.



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# File 'lib/rtp/receiver.rb', line 58

def initialize(options={})
  @rtp_port           = options[:rtp_port]           || 6970
  @rtcp_port          = @rtp_port + 1
  @transport_protocol = options[:transport_protocol] || :UDP
  @ip_address         = options[:ip_address]         || '0.0.0.0'
  @strip_headers      = options[:strip_headers]      || false
  @capture_file       = options[:capture_file]       ||
    Tempfile.new(DEFAULT_CAPFILE_NAME)

  at_exit do
    unless @capture_file.closed?
      log "Closing and deleting capture capture file..."
      @capture_file.close
      @capture_file.unlink
    end
  end

  @socket = nil
  @listener = nil
  @packet_writer = nil
  @packets = Queue.new
  @packet_timestamps = []
end

Instance Attribute Details

#capture_file ⇒ File (readonly)

Returns The file to capture the RTP data to.

Returns:

  • (File) —

    The file to capture the RTP data to.



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# File 'lib/rtp/receiver.rb', line 28

def capture_file
  @capture_file
end

#ip_address ⇒ String

Returns The IP address to receive RTP data on.

Returns:

  • (String) —

    The IP address to receive RTP data on.



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# File 'lib/rtp/receiver.rb', line 45

def ip_address
  @ip_address
end

#packet_timestamps ⇒ Array<Time> (readonly)

Returns The packet receipt timestamps.

Returns:

  • (Array<Time>) —

    The packet receipt timestamps.



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# File 'lib/rtp/receiver.rb', line 31

def packet_timestamps
  @packet_timestamps
end

#rtcp_port ⇒ Fixnum (readonly)

Returns Added for clarifying the roles of ports; not currently used though.

Returns:

  • (Fixnum) —

    Added for clarifying the roles of ports; not currently used though.



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# File 'lib/rtp/receiver.rb', line 38

def rtcp_port
  @rtcp_port
end

#rtp_port ⇒ Fixnum

Returns The port on which to capture RTP data.

Returns:

  • (Fixnum) —

    The port on which to capture RTP data.



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# File 'lib/rtp/receiver.rb', line 34

def rtp_port
  @rtp_port
end

#transport_protocol ⇒ Symbol

Returns The type of socket to use for capturing the RTP data. :UDP or :TCP.

Returns:

  • (Symbol) —

    The type of socket to use for capturing the RTP data. :UDP or :TCP.



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# File 'lib/rtp/receiver.rb', line 42

def transport_protocol
  @transport_protocol
end

Instance Method Details

#ip_addressing_type ⇒ Symbol

Returns The IP addressing type to use for capturing the data. :multicast or +:unicast:.

Returns:

  • (Symbol) —

    The IP addressing type to use for capturing the data. :multicast or +:unicast:.



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# File 'lib/rtp/receiver.rb', line 170

def ip_addressing_type
  multicast? ? :multicast : :unicast
end

#listening? ⇒ Boolean

Returns true if the listener thread is running; false if not.

Returns:

  • (Boolean) —

    true if the listener thread is running; false if not.



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# File 'lib/rtp/receiver.rb', line 137

def listening?
  !@listener.nil? ? @listener.alive? : false
end

#multicast? ⇒ Boolean

Returns true if ip_address is a multicast address or not.

Returns:

  • (Boolean) —

    true if ip_address is a multicast address or not.



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# File 'lib/rtp/receiver.rb', line 158

def multicast?
  first_octet = @ip_address.match(/^(\d\d\d?)/).to_s.to_i
  first_octet >= 224 && first_octet <= 239
end

#running? ⇒ Boolean

Returns true if the Receiver is listening and writing packets.

Returns:

  • (Boolean) —

    true if the Receiver is listening and writing packets.



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# File 'lib/rtp/receiver.rb', line 147

def running?
  listening? && writing_packets?
end

#start {|RTP::Packet| ... } ⇒ Boolean

Starts the packet writer (buffer) and listener.

If a block is given, this will yield each parsed packet as an RTP::Packet. This lets you inspect packets as they come in:

Examples:

Just the packet

receiver = RTP::Receiver.new
receiver.start do |packet|
  puts packet.sequence_number
end

The packet and its timestamp

receiver = RTP::Receiver.new
receiver.start do |packet, timestamp|
  puts packet.sequence_number
  puts timestamp
end

Yields:

  • (RTP::Packet) —

    Each parsed packet that comes in over the wire.

  • (Time) —

    The timestamp from the packet as it was received on the socket.

Returns:

  • (Boolean) —

    true if started successfully.



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# File 'lib/rtp/receiver.rb', line 104

def start(&block)
  return false if running?
  log "Starting receiving on port #{@rtp_port}..."

  @packet_writer = start_packet_writer(&block)
  @packet_writer.abort_on_exception = true

  @socket = init_socket(@transport_protocol, @rtp_port, @ip_address)

  @listener = start_listener(@socket)
  @listener.abort_on_exception = true

  running?
end

#stop ⇒ Boolean

Stops the listener and packet writer threads.

Returns:

  • (Boolean) —

    true if stopped successfully.



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# File 'lib/rtp/receiver.rb', line 122

def stop
  return false if !running?

  log "Stopping #{self.class} on port #{@rtp_port}..."
  stop_listener
  log "listening? #{listening?}"

  stop_packet_writer
  log "writing packets? #{writing_packets?}"
  log "running? #{running?}"

  !running?
end

#unicast? ⇒ Boolean

Returns true if ip_address is a unicast address or not.

Returns:

  • (Boolean) —

    true if ip_address is a unicast address or not.



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# File 'lib/rtp/receiver.rb', line 164

def unicast?
  !multicast?
end

#writing_packets? ⇒ Boolean

Returns true if ready to write packets to file.

Returns:

  • (Boolean) —

    true if ready to write packets to file.



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# File 'lib/rtp/receiver.rb', line 142

def writing_packets?
  !@packet_writer.nil? ? @packet_writer.alive? : false
end