rtp¶ ↑

github.com/turboladen/rtp

<img src=“https://secure.travis-ci.org/turboladen/rtp.png?branch=master” alt=“Build Status” />

This is a RTP library that provides the most basic features of the Real-Time Transport Protocol (RTP, RFC 3550). While the protocol allows for extensions that define new ways for transporting encoded audio/video, this library doesn’t yet deal with any specific media types. My current goal is simply for transporting a single RTP stream of data and allowing you to inspect its packets.

Features:

• Receive a single RTP stream over UDP or TCP, unicast or multicast

• Parse RTP packet headers

• Inspect packets on the fly

Future goals will include:

• RTCP

• Multiplexed sessions

• Decoding of basic audio/video codec headers

• Decoding of some popular A/V extension headers (h.264, et al.)

• An easy way to hand over your data to an app that will decode your A/V stream(s)

• Sending an RTP stream

With its default settings, an {RTP::Receiver} will open a UDP socket on port 6790, within a Thread, on 0.0.0.0 and capture the data it receives to a file.

receiver = RTP::Receiver.new      # Uses a Tempfile by default
receiver.rtp_port                 # => 6790
receiver.transport_protocol       # => :UDP
receiver.multicast?               # => false
receiver.unicast?                 # => true
receiver.start
sleep 5
receiver.stop
receiver.capture_file.size        # => 20040

To init a Receiver with some other options…

options = {
  rtp_port: 9000,
  transport_protocol: :TCP,
  ip_address: '239.255.255.251',  # Multicast!
  strip_headers: true,            # Strips RTP headers before writing to file
  capture_file: File.new('data.rtp', 'wb')
}
receiver = RTP::Receiver.new(options)
receiver.start
sleep 5
receiver.stop
receiver.capture_file.size        # => 18848

To inspect (and do what you like with) packets as they come in…

receiver = RTP::Receiver.new
receiver.start do |packet|
  puts "Sequence number: #{packet.sequence_number}"  # => Sequence number: 2931830
end
sleep 5
receiver.stop
receiver.capture_file.size        # => 0

Notice how no data was written to file when the block was passed to #start. The idea there is to save on I/O; if you’re inspecting packets, it’s not fair to assume you want to save the data to a file. If you do, however, in that case, you can simply do so within the block.

• (Tested) Rubies

  • 1.9.2

  • 1.9.3

• RubyGems:

  • bindata

  • log_switch

$ gem install rtp

After checking out the source, run:

$ bundle install

This task will install any missing dependencies for you.