You're seeing just the callback handle_stopped_to_prepared, go back to Membrane.Element.Base module for more information.
Link to this callback

handle_stopped_to_prepared(context, state)

View Source (optional)


  context :: Membrane.Element.CallbackContext.PlaybackChange.t(),
  state :: Membrane.Element.state_t()
) :: callback_return_t()

Callback invoked when element goes to :prepared state from state :stopped and should get ready to enter :playing state.

Usually most resources used by the element are allocated here. For example, if element opens a file, this is the place to try to actually open it and return error if that has failed. Such resources should be released in handle_prepared_to_stopped/2.