README.md

Membrane Tee Plugin

This package provides elements that can be used to branch stream processing in pipeline, e.g. send data from one source to two or more sinks.

Installation

This package can be installed by adding membrane_tee_plugin to your list of dependencies in mix.exs:

def deps do
  [
	{:membrane_tee_plugin, "~> 0.12.0"}
  ]
end

The docs can be found at HexDocs.

Examples

Membrane.Tee.Parallel

This element has dynamic :output pads working in :pull mode. Packets are forwarded only when all output pads send demands, which means that the slowest output pad dictates the speed of processing data.

Playing this pipeline should result in copying the source file to all destination files (sinks). Before playing it, make sure that the source file exists, e.g. like this: echo "Membrane Framework is cool" > /tmp/source_text_file

You also need :membrane_file_plugin in project dependencies to run this pipeline.

defmodule FileMultiForwardPipeline do
  use Membrane.Pipeline
  alias Membrane.{File, Tee}

  @impl true
  def handle_init(_ctx, _state) do

    links = [
      child(:tee, Tee.Parallel),
      child(file_src, %File.Source{location: "/tmp/source_text_file"}) 
      |> get_child(:tee) |> child(:file_sink1, %File.Sink{location: "/tmp/destination_file1"}),
      get_child(:tee) |> child(:file_sink2, %File.Sink{location: "/tmp/destination_file2"})
    ]

    {[spec: links], %{}}
  end
end

Membrane.Tee.PushOutput

This element works like Membrane.Tee.Parallel but doesn't care about the speed of processing of elements connected to its outputs. If such an element doesn't process data fast enough, it crashes with the toilet overflow error. In other words, the input pad dictates the speed of processing.

Membrane.Tee.Master

This element has one :master output pad that dictates the speed of processing data and dynamic :copy pad working in :push mode mirroring :master pad.

Playing this pipeline should result in playing mp3 source file and copying it to the destination file. Before playing it, make sure you have valid source file, e.g. this one.

You also need :membrane_file_plugin and :membrane_portaudio_plugin in project dependencies to run this pipeline.

defmodule AudioPlayAndCopyPipeline do
  use Membrane.Pipeline
  alias Membrane.{File, Tee, PortAudio}

  @impl true
  def handle_init(_ctx, _opts) do
    links = [
      child(:tee, Tee.Master),
      child(:file_src, %File.Source{location: "/tmp/source_file.mp3"}) |> get_child(:tee),
      get_child(:tee) |> via_out(:master) |> child(:audio_sink,PortAudio.Sink),
      get_child(:tee) |> via_out(:copy) |> to(:file_sink,%File.Sink{location: "/tmp/destination_file.mp3"})
    ]

    {[spec: links], %{}}
  end
end

Copyright and License

Copyright 2019, Software Mansion

Licensed under the Apache License, Version 2.0