Membrane Opus plugin

Opus encoder and decoder.

It is a part of Membrane Multimedia Framework.

Installation

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

def deps do
  [
    {:membrane_opus_plugin, "~> 0.20.4"}
  ]
end

This package depends on libopus library. The precompiled builds will be pulled and linked automatically. However, should there be any problems, consider installing it manually.

Manual instalation of dependencies

Ubuntu

sudo apt-get install libopus-dev

Arch/Manjaro

pacman -S opus

MacOS

brew install opus

MacOS M1/M2 (Apple silicon)

On Apple M1/M2 chips, one needs to export variables:

export C_INCLUDE_PATH=$C_INCLUDE_PATH:$(brew --cellar)/opus/1.3.1/include
export LIBRARY_PATH=$LIBRARY_PATH:$(brew --cellar)/opus/1.3.1/lib

On different local setups, directory and version names may differ.

Usage

Encoder

The pipeline encodes a sample raw file and saves it as an opus file:

defmodule Membrane.ReleaseTest.Pipeline do
  use Membrane.Pipeline
  alias Membrane.RawAudio

  @input_filename "/tmp/input.raw"
  @output_filename "/tmp/output.opus"

  @impl true
  def handle_init(_ctx, _options) do
    structure = 
      child(:source, %Membrane.File.Source{
        location: @input_filename
      })
      |> child(:encoder, %Membrane.Opus.Encoder{
        application: :audio,
        input_stream_format: %RawAudio{
          channels: 2,
          sample_format: :s16le,
          sample_rate: 48_000
        }
      })
      |> child(:parser, %Membrane.Opus.Parser{delimitation: :delimit})
      |> child(:sink, %Membrane.File.Sink{
        location: @output_filename
      })

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

Opus audio generally needs to be packaged in an Ogg container in order to be played by a media player. See Membrane.Ogg.Payloader in the Membrane Ogg Plugin.

Decoder

The pipeline parses, decodes a sample opus file and then saves it as a raw file:

defmodule Membrane.ReleaseTest.Pipeline2 do
  use Membrane.Pipeline

  @input_filename "/tmp/input.raw"
  @output_filename "/tmp/output.opus"

  @impl true
  def handle_init(_ctx, _options) do
    structure = 
      child(:source, %Membrane.File.Source{
        location: @input_filename
      })
      |> child(:parser, Membrane.Opus.Parser)
      |> child(:opus, Membrane.Opus.Decoder)
      |> child(:sink, %Membrane.File.Sink{
        location: @output_filename
      })

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

Copyright and License

Copyright 2019, Software Mansion

Licensed under the Apache License, Version 2.0