Membrane Core v0.4.3 Membrane.Pipeline behaviour View Source

Module containing functions for constructing and supervising pipelines.

Pipelines are units that make it possible to instantiate, link and manage elements in convenient way (actually elements should always be used inside a pipeline). Linking elements together enables them to pass data to one another, and process it in different ways.

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Types

Type describing actions that can be returned from pipeline callbacks.

Type that defines all valid return values from most callbacks.

Action that sends a message to element identified by name.

Defines options that can be passed to start/3 / start_link/3 and received in handle_init/1 callback.

Action that stops, unlinks and removes specified child/children from pipeline.

Action that instantiates elements and links them according to Membrane.Pipeline.Spec.

Functions

Returns a specification to start this module under a supervisor.

Checks whether module is a pipeline.

Changes playback state to :playing.

Changes playback state to :prepared.

Does the same as start_link/3 but starts process outside of supervision tree.

Starts the Pipeline based on given module and links it to the current process.

Changes playback state to :stopped.

Changes pipeline's playback state to :stopped and terminates its process

Callbacks

Callback invoked when pipeline's element receives end_of_stream event.

Callback invoked when pipeline's element receives start_of_stream event.

Callback invoked on initialization of pipeline process. It should parse options and initialize element internal state. Internally it is invoked inside GenServer.init/1 callback.

Callback invoked when a notification comes in from an element.

Callback invoked when pipeline receives a message that is not recognized as an internal membrane message.

Callback invoked when pipeline transition from :playing to :prepared state has finished, that is all of its elements are prepared to be stopped.

Callback invoked when pipeline is in :playing state, i.e. all its elements are in this state.

Callback invoked when pipeline is in :playing state, i.e. all its elements are in this state.

Callback invoked when pipeline is shutting down. Internally called in GenServer.terminate/2 callback.

Callback invoked when Membrane.Pipeline.Spec is linked and in the same playback state as pipeline.

Callback invoked when pipeline transition from :stopped to :prepared state has finished, that is all of its elements are prepared to enter :playing state.

Enables to check whether module is membrane pipeline

Link to this section Types

Type describing actions that can be returned from pipeline callbacks.

Returning actions is a way of pipeline interaction with its elements and other parts of framework.

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callback_return_t()

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callback_return_t() ::
  {:ok | {:ok, [action_t()]} | {:error, any()},
   Membrane.Pipeline.State.internal_state_t()}
  | {:error, any()}

Type that defines all valid return values from most callbacks.

In case of error, a callback is supposed to return {:error, any} if it is not passed state, and {{:error, any}, state} otherwise.

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forward_action_t()

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forward_action_t() ::
  {:forward, {Membrane.Element.name_t(), Membrane.Notification.t()}}

Action that sends a message to element identified by name.

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pipeline_options_t()

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pipeline_options_t() :: any()

Defines options that can be passed to start/3 / start_link/3 and received in handle_init/1 callback.

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remove_child_action_t()

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remove_child_action_t() ::
  {:remove_child, Membrane.Element.name_t() | [Membrane.Element.name_t()]}

Action that stops, unlinks and removes specified child/children from pipeline.

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spec_action_t()

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spec_action_t() :: {:spec, Membrane.Pipeline.Spec.t()}

Action that instantiates elements and links them according to Membrane.Pipeline.Spec.

Elements playback state is changed to the current pipeline state. c:handle_spec_started callback is executed once it happens.

Link to this section Functions

Returns a specification to start this module under a supervisor.

See Supervisor.

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do_handle_action(arg1, arg2, params, state)

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pipeline?(module)

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pipeline?(module()) :: boolean()

Checks whether module is a pipeline.

Changes playback state to :playing.

An alias for change_playback_state/2 with proper state.

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prepare(pid)

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prepare(pid()) :: :ok

Changes playback state to :prepared.

An alias for change_playback_state/2 with proper state.

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start(module, pipeline_options \\ nil, process_options \\ [])

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start(
  module(),
  pipeline_options :: pipeline_options_t(),
  process_options :: GenServer.options()
) :: GenServer.on_start()

Does the same as start_link/3 but starts process outside of supervision tree.

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start_link(module, pipeline_options \\ nil, process_options \\ [])

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start_link(
  module(),
  pipeline_options :: pipeline_options_t(),
  process_options :: GenServer.options()
) :: GenServer.on_start()

Starts the Pipeline based on given module and links it to the current process.

Pipeline options are passed to module's handle_init/1 callback.

Process options are internally passed to GenServer.start_link/3.

Returns the same values as GenServer.start_link/3.

Changes playback state to :stopped.

An alias for change_playback_state/2 with proper state.

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stop_and_terminate(pipeline)

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stop_and_terminate(pipeline :: pid()) :: :ok

Changes pipeline's playback state to :stopped and terminates its process

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handle_element_end_of_stream({}, state)

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handle_element_end_of_stream(
  {Membrane.Element.name_t(), Membrane.Element.Pad.ref_t()},
  state :: Membrane.Pipeline.State.internal_state_t()
) :: callback_return_t()

Callback invoked when pipeline's element receives end_of_stream event.

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handle_element_start_of_stream({}, state)

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handle_element_start_of_stream(
  {Membrane.Element.name_t(), Membrane.Element.Pad.ref_t()},
  state :: Membrane.Pipeline.State.internal_state_t()
) :: callback_return_t()

Callback invoked when pipeline's element receives start_of_stream event.

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handle_init(options)

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handle_init(options :: pipeline_options_t()) :: callback_return_t()

Callback invoked on initialization of pipeline process. It should parse options and initialize element internal state. Internally it is invoked inside GenServer.init/1 callback.

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handle_notification(notification, element, state)

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handle_notification(
  notification :: Membrane.Notification.t(),
  element :: Membrane.Element.name_t(),
  state :: Membrane.Pipeline.State.internal_state_t()
) :: callback_return_t()

Callback invoked when a notification comes in from an element.

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handle_other(message, state)

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handle_other(
  message :: any(),
  state :: Membrane.Pipeline.State.internal_state_t()
) :: callback_return_t()

Callback invoked when pipeline receives a message that is not recognized as an internal membrane message.

Useful for receiving ticks from timer, data sent from NIFs or other stuff.

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handle_playing_to_prepared(state)

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handle_playing_to_prepared(state :: Membrane.Pipeline.State.internal_state_t()) ::
  callback_return_t()

Callback invoked when pipeline transition from :playing to :prepared state has finished, that is all of its elements are prepared to be stopped.

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handle_prepared_to_playing(state)

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handle_prepared_to_playing(state :: Membrane.Pipeline.State.internal_state_t()) ::
  callback_return_t()

Callback invoked when pipeline is in :playing state, i.e. all its elements are in this state.

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handle_prepared_to_stopped(state)

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handle_prepared_to_stopped(state :: Membrane.Pipeline.State.internal_state_t()) ::
  callback_return_t()

Callback invoked when pipeline is in :playing state, i.e. all its elements are in this state.

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handle_shutdown(reason, state)

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handle_shutdown(reason, state :: Membrane.Pipeline.State.internal_state_t()) ::
  :ok
when reason: :normal | :shutdown | {:shutdown, any()}

Callback invoked when pipeline is shutting down. Internally called in GenServer.terminate/2 callback.

Useful for any cleanup required.

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handle_spec_started(elements, state)

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handle_spec_started(
  elements :: [Membrane.Element.name_t()],
  state :: Membrane.Pipeline.State.internal_state_t()
) :: callback_return_t()

Callback invoked when Membrane.Pipeline.Spec is linked and in the same playback state as pipeline.

Spec can be started from handle_init/1 callback or as spec_action_t/0 action.

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handle_stopped_to_prepared(state)

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handle_stopped_to_prepared(state :: Membrane.Pipeline.State.internal_state_t()) ::
  callback_return_t()

Callback invoked when pipeline transition from :stopped to :prepared state has finished, that is all of its elements are prepared to enter :playing state.

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membrane_pipeline?()

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membrane_pipeline?() :: true

Enables to check whether module is membrane pipeline