Add first working example

camera_to_hls_nerves/.formatter.exs

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+# Used by "mix format"
+[
+  inputs: [
+    "{mix,.formatter}.exs",
+    "{config,lib,test}/**/*.{ex,exs}",
+    "rootfs_overlay/etc/iex.exs"
+  ],
+  import_deps: [:membrane_core, :unifex]
+]

camera_to_hls_nerves/.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump

camera_to_hls_nerves/README.md

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+# CameraToHlsNerves
+
+**TODO: Add description**
+
+## Targets
+
+Nerves applications produce images for hardware targets based on the
+`MIX_TARGET` environment variable. If `MIX_TARGET` is unset, `mix` builds an
+image that runs on the host (e.g., your laptop). This is useful for executing
+logic tests, running utilities, and debugging. Other targets are represented by
+a short name like `rpi3` that maps to a Nerves system image for that platform.
+All of this logic is in the generated `mix.exs` and may be customized. For more
+information about targets see:
+
+https://hexdocs.pm/nerves/targets.html#content
+
+## Getting Started
+
+To start your Nerves app:
+  * `export MIX_TARGET=my_target` or prefix every command with
+    `MIX_TARGET=my_target`. For example, `MIX_TARGET=rpi3`
+  * Install dependencies with `mix deps.get`
+  * Create firmware with `mix firmware`
+  * Burn to an SD card with `mix burn`
+
+## Learn more
+
+  * Official docs: https://hexdocs.pm/nerves/getting-started.html
+  * Official website: https://nerves-project.org/
+  * Forum: https://elixirforum.com/c/nerves-forum
+  * Discussion Slack elixir-lang #nerves ([Invite](https://elixir-slackin.herokuapp.com/))
+  * Source: https://github.com/nerves-project/nerves

camera_to_hls_nerves/config/config.exs

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+# This file is responsible for configuring your application and its
+# dependencies.
+#
+# This configuration file is loaded before any dependency and is restricted to
+# this project.
+import Config
+
+# Enable the Nerves integration with Mix
+Application.start(:nerves_bootstrap)
+
+config :camera_to_hls_nerves, target: Mix.target()
+
+# Customize non-Elixir parts of the firmware. See
+# https://hexdocs.pm/nerves/advanced-configuration.html for details.
+
+config :nerves, :firmware, rootfs_overlay: "rootfs_overlay"
+
+# Set the SOURCE_DATE_EPOCH date for reproducible builds.
+# See https://reproducible-builds.org/docs/source-date-epoch/ for more information
+
+config :nerves, source_date_epoch: "1698662793"
+if Mix.target() == :host do
+  import_config "host.exs"
+else
+  import_config "target.exs"
+end

camera_to_hls_nerves/config/host.exs

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+import Config
+
+# Add configuration that is only needed when running on the host here.
+
+config :nerves_runtime,
+  kv_backend:
+    {Nerves.Runtime.KVBackend.InMemory,
+     contents: %{
+       # The KV store on Nerves systems is typically read from UBoot-env, but
+       # this allows us to use a pre-populated InMemory store when running on
+       # host for development and testing.
+       #
+       # https://hexdocs.pm/nerves_runtime/readme.html#using-nerves_runtime-in-tests
+       # https://hexdocs.pm/nerves_runtime/readme.html#nerves-system-and-firmware-metadata
+
+       "nerves_fw_active" => "a",
+       "a.nerves_fw_architecture" => "generic",
+       "a.nerves_fw_description" => "N/A",
+       "a.nerves_fw_platform" => "host",
+       "a.nerves_fw_version" => "0.0.0"
+     }}

camera_to_hls_nerves/config/target.exs

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+import Config
+
+# Use Ringlogger as the logger backend and remove :console.
+# See https://hexdocs.pm/ring_logger/readme.html for more information on
+# configuring ring_logger.
+
+config :logger, backends: [RingLogger]
+
+# Use shoehorn to start the main application. See the shoehorn
+# library documentation for more control in ordering how OTP
+# applications are started and handling failures.
+
+config :shoehorn, init: [:nerves_runtime, :nerves_pack]
+
+# Erlinit can be configured without a rootfs_overlay. See
+# https://github.com/nerves-project/erlinit/ for more information on
+# configuring erlinit.
+
+# Advance the system clock on devices without real-time clocks.
+config :nerves, :erlinit, update_clock: true
+
+# Configure the device for SSH IEx prompt access and firmware updates
+#
+# * See https://hexdocs.pm/nerves_ssh/readme.html for general SSH configuration
+# * See https://hexdocs.pm/ssh_subsystem_fwup/readme.html for firmware updates
+
+keys =
+  [
+    Path.join([System.user_home!(), ".ssh", "id_rsa.pub"]),
+    Path.join([System.user_home!(), ".ssh", "id_ecdsa.pub"]),
+    Path.join([System.user_home!(), ".ssh", "id_ed25519.pub"])
+  ]
+  |> Enum.filter(&File.exists?/1)
+
+if keys == [],
+  do:
+    Mix.raise("""
+    No SSH public keys found in ~/.ssh. An ssh authorized key is needed to
+    log into the Nerves device and update firmware on it using ssh.
+    See your project's config.exs for this error message.
+    """)
+
+config :nerves_ssh,
+  authorized_keys: Enum.map(keys, &File.read!/1)
+
+# Configure the network using vintage_net
+#
+# Update regulatory_domain to your 2-letter country code E.g., "US"
+#
+# See https://github.com/nerves-networking/vintage_net for more information
+
+network = %{
+  key_mgmt: :wpa_psk,
+  ssid:
+    case System.fetch_env("SSID") do
+      {:ok, ssid} -> ssid
+      :error -> raise "SSID not provided, set the environment variable SSID"
+    end,
+  psk:
+    case System.fetch_env("PSK") do
+      {:ok, psk} -> psk
+      :error -> ""
+    end
+}
+
+config :vintage_net,
+  regulatory_domain: "00",
+  config: [
+    {"usb0", %{type: VintageNetDirect}},
+    {"eth0",
+     %{
+       type: VintageNetEthernet,
+       ipv4: %{method: :dhcp}
+     }},
+    {"wlan0",
+     %{
+       type: VintageNetWiFi,
+       vintage_net_wifi: %{
+         networks: [network]
+       },
+       ipv4: %{method: :dhcp}
+     }}
+  ]
+
+config :mdns_lite,
+  # The `hosts` key specifies what hostnames mdns_lite advertises.  `:hostname`
+  # advertises the device's hostname.local. For the official Nerves systems, this
+  # is "nerves-<4 digit serial#>.local".  The `"nerves"` host causes mdns_lite
+  # to advertise "nerves.local" for convenience. If more than one Nerves device
+  # is on the network, it is recommended to delete "nerves" from the list
+  # because otherwise any of the devices may respond to nerves.local leading to
+  # unpredictable behavior.
+
+  hosts: [:hostname, "nerves"],
+  ttl: 120,
+
+  # Advertise the following services over mDNS.
+  services: [
+    %{
+      protocol: "ssh",
+      transport: "tcp",
+      port: 22
+    },
+    %{
+      protocol: "sftp-ssh",
+      transport: "tcp",
+      port: 22
+    },
+    %{
+      protocol: "epmd",
+      transport: "tcp",
+      port: 4369
+    }
+  ]
+
+# Import target specific config. This must remain at the bottom
+# of this file so it overrides the configuration defined above.
+# Uncomment to use target specific configurations
+
+# import_config "#{Mix.target()}.exs"

camera_to_hls_nerves/lib/nerves_membrane_demo.ex

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+defmodule CameraToHlsNerves do
+  @moduledoc """
+  Example of streaming live feed from a RaspberryPi camera to a browser with HLS
+  """
+end

camera_to_hls_nerves/lib/nerves_membrane_demo/application.ex

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+defmodule CameraToHlsNerves.Application do
+  use Application
+
+  def start(_type, _args) do
+
+    File.rm_rf!("/data/output")
+    File.mkdir!("/data/output")
+    File.cd!("/")
+
+    :inets.start()
+
+    httpd_options = [
+      bind_address: ~c"0.0.0.0",
+      port: 8000,
+      document_root: ~c".",
+      server_name: ~c"camera_to_hls_nerves",
+      server_root: ~c"/"
+    ]
+
+    children = [
+      %{
+        id: :http_server,
+        start: {:inets, :start, [:httpd, httpd_options]}
+      },
+      CameraToHlsNerves.Pipeline
+    ]
+
+    Supervisor.start_link(children, strategy: :one_for_one)
+  end
+end

camera_to_hls_nerves/lib/nerves_membrane_demo/pipeline.ex

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+defmodule CameraToHlsNerves.Pipeline do
+  use Membrane.Pipeline
+
+  def start_link(opts) do
+    Membrane.Pipeline.start_link(__MODULE__, opts)
+  end
+
+  @impl true
+  def handle_init(_ctx, _opts) do
+    spec = [
+      child(:source, %Membrane.Rpicam.Source{framerate: {30, 1}})
+      |> child(:parser, %Membrane.H264.Parser{generate_best_effort_timestamps: %{framerate: {30, 1}}})
+      |> via_in(:input,
+        options: [
+          encoding: :H264,
+          track_name: "my_track",
+          segment_duration: Membrane.Time.seconds(5)
+        ]
+      )
+      |> child(:hls_sink, %Membrane.HTTPAdaptiveStream.SinkBin{
+        manifest_module: Membrane.HTTPAdaptiveStream.HLS,
+        storage: %Membrane.HTTPAdaptiveStream.Storages.FileStorage{directory: "/data/output"},
+        target_window_duration: Membrane.Time.seconds(10)
+      })
+    ]
+
+    # Not waiting causes libcamera-vid to crash
+    Process.sleep(50)
+
+    {[spec: spec], %{}}
+  end
+end

camera_to_hls_nerves/mix.exs

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+defmodule CameraToHlsNerves.MixProject do
+  use Mix.Project
+
+  @app :camera_to_hls_nerves
+  @version "0.1.0"
+  @all_targets [
+    :rpi,
+    :rpi0,
+    :rpi2,
+    :rpi3,
+    :rpi3a,
+    :rpi4,
+    :bbb,
+    :osd32mp1,
+    :x86_64,
+    :grisp2,
+    :mangopi_mq_pro
+  ]
+
+  def project do
+    [
+      app: @app,
+      version: @version,
+      elixir: "~> 1.11",
+      archives: [nerves_bootstrap: "~> 1.12"],
+      start_permanent: Mix.env() == :prod,
+      deps: deps(),
+      releases: [{@app, release()}],
+      preferred_cli_target: [run: :host, test: :host]
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      mod: {CameraToHlsNerves.Application, []},
+      extra_applications: [:logger, :runtime_tools, :inets]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # Dependencies for all targets
+      {:nerves, "~> 1.10", runtime: false},
+      {:shoehorn, "~> 0.9.1"},
+      {:ring_logger, "~> 0.10.0"},
+      {:toolshed, "~> 0.3.0"},
+      {:httpoison, "~> 2.0"},
+
+      {:membrane_rpicam_plugin, path: "~/Membrane/membrane_rpicam_plugin", override: true},
+      {:membrane_h264_plugin, "~> 0.9.0"},
+      {:membrane_http_adaptive_stream_plugin, "~> 0.18.0"},
+      {:membrane_aac_plugin, github: "membraneframework/membrane_aac_plugin", branch: "remove-crc-calculation", override: true},
+
+      # Allow Nerves.Runtime on host to support development, testing and CI.
+      # See config/host.exs for usage.
+      {:nerves_runtime, "~> 0.13.0"},
+
+      # Dependencies for all targets except :host
+      {:nerves_pack, "~> 0.7.0", targets: @all_targets},
+
+      # Dependencies for specific targets
+      # NOTE: It's generally low risk and recommended to follow minor version
+      # bumps to Nerves systems. Since these include Linux kernel and Erlang
+      # version updates, please review their release notes in case
+      # changes to your application are needed.
+      {:nerves_system_rpi, "~> 1.24", runtime: false, targets: :rpi},
+      {:nerves_system_rpi0, "~> 1.24", runtime: false, targets: :rpi0},
+      {:nerves_system_rpi2, "~> 1.24", runtime: false, targets: :rpi2},
+      {:nerves_system_rpi3, "~> 1.24", runtime: false, targets: :rpi3},
+      {:nerves_system_rpi3a, "~> 1.24", runtime: false, targets: :rpi3a},
+      {:nerves_system_rpi4, "~> 1.24", runtime: false, targets: :rpi4},
+      {:nerves_system_bbb, "~> 2.19", runtime: false, targets: :bbb},
+      {:nerves_system_osd32mp1, "~> 0.15", runtime: false, targets: :osd32mp1},
+      {:nerves_system_x86_64, "~> 1.24", runtime: false, targets: :x86_64},
+      {:nerves_system_grisp2, "~> 0.8", runtime: false, targets: :grisp2},
+      {:nerves_system_mangopi_mq_pro, "~> 0.6", runtime: false, targets: :mangopi_mq_pro}
+    ]
+  end
+
+  def release do
+    [
+      overwrite: true,
+      # Erlang distribution is not started automatically.
+      # See https://hexdocs.pm/nerves_pack/readme.html#erlang-distribution
+      cookie: "#{@app}_cookie",
+      include_erts: &Nerves.Release.erts/0,
+      steps: [&Nerves.Release.init/1, :assemble],
+      strip_beams: Mix.env() == :prod or [keep: ["Docs"]]
+    ]
+  end
+end