Membrane Core v0.2.2 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

Changes the playback state to the new_state

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

Callbacks

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 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() View Source
callback_return_t() ::
  Membrane.Core.CallbackHandler.callback_return_t(
    action_t(),
    Membrane.Pipeline.State.internal_state_t()
  )

Type that defines all valid return values from most callbacks.

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forward_action_t() View Source
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() View Source
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() View Source
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() View Source
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

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change_playback_state(pid, new_state) View Source
change_playback_state(pid(), Membrane.Core.Playback.state_t()) :: :ok

Changes the playback state to the new_state.

Returns a specification to start this module under a supervisor.

See Supervisor.

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pipeline?(module) View Source
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) View Source
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 \\ []) View Source
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 \\ []) View Source
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) View Source
stop_and_terminate(pipeline :: pid()) :: :ok

Link to this section Callbacks

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handle_init(options) View Source
handle_init(options :: pipeline_options_t()) ::
  {{:ok, Membrane.Pipeline.Spec.t()},
   Membrane.Pipeline.State.internal_state_t()}
  | {:error, any()}

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) View Source
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) View Source
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) View Source
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) View Source
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) View Source
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_spec_started(elements, state) View Source
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) View Source
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?() View Source
membrane_pipeline?() :: true

Enables to check whether module is membrane pipeline