View Source Membrane.Testing.Source (Membrane Core v1.0.1)
Testing Element for supplying data based on generator function or payloads passed through options.
Example usage
As mentioned earlier you can use this element in one of two ways, providing
either a generator function or an Enumerable.t
.
If you provide an Enumerable.t
with payloads, then each of those payloads will
be wrapped in a Membrane.Buffer
and sent through :output
pad.
%Source{output: [0xA1, 0xB2, 0xC3, 0xD4]}
In order to specify Membrane.Testing.Source
with generator function you need
to provide initial state and function that matches generator/0
type. This
function should take state and demand size as its arguments and return
a tuple consisting of actions that element will return during the
Membrane.Element.WithOutputPads.handle_demand/5
callback and new state.
generator_function = fn state, size ->
#generate some buffers
{actions, state + 1}
end
%Source{output: {1, generator_function}}
Element options
Passed via struct Membrane.Testing.Source.t/0
output
Enum.t() | {initial_state :: any(), generator}
Default value:
{0, &Membrane.Testing.Source.default_buf_gen/2}
Ifoutput
is an Enumerable, then each element of it will be sent through the:output
pad, followed byMembrane.Element.Action.end_of_stream/0
. Each element of the Enumerable must be eitherMembrane.Buffer.t/0
orMembrane.Payload.t/0
. In the latter case, it will be automatically wrapped intoMembrane.Buffer.t/0
before sending.Otherwise, if
output
is a{initial_state, function}
tuple then the the function will be invoked each timehandle_demand
is called. It is an action generator that takes two arguments. The first argument is the state that is initially set toinitial_state
. The second one defines the size of the demand. Such function should return{actions, next_state}
whereactions
is a list of actions that will be returned fromhandle_demand/4
andnext_state
is the value that will be used for the next call.stream_format
struct()
Default value:
%Membrane.RemoteStream{content_format: nil, type: :bytestream}
StreamFormat to be sent before theoutput
.
Pads
:output
Accepted formats:
_any
Direction: | :output |
Availability: | :always |
Flow control: | :manual |
Demand unit: | nil |
Summary
Functions
Returns description of options available for this module
Creates output with generator function from list of buffers.
Types
@type generator() :: (state :: any(), buffers_cnt :: pos_integer() -> {[Membrane.Element.Action.t()], state :: any()})
@type t() :: %Membrane.Testing.Source{ output: Enum.t() | {initial_state :: any(), generator()}, stream_format: struct() }
Struct containing options for Membrane.Testing.Source
Functions
@spec default_buf_gen(integer(), integer()) :: {[Membrane.Element.Action.t()], integer()}
@spec options() :: keyword()
Returns description of options available for this module
@spec output_from_buffers([Membrane.Buffer.t()]) :: {[Membrane.Buffer.t()], generator()}
Creates output with generator function from list of buffers.