defmodule Membrane.SDL.Player do
@moduledoc """
This module provides an [SDL](https://www.libsdl.org/)-based video player sink.
"""
use Bunch
use Membrane.Sink
require Membrane.Logger
require Unifex.CNode
alias Membrane.{Buffer, Time}
alias Membrane.RawVideo
alias Unifex.CNode
# The measured latency needed to show a frame on a screen.
@latency 20 |> Time.milliseconds()
def_input_pad :input, accepted_format: RawVideo, demand_unit: :buffers
@impl true
def handle_init(_options, _ctx) do
state = %{cnode: nil, timer_started?: false}
{[latency: @latency], state}
end
@impl true
def handle_setup(_ctx, state) do
{:ok, cnode} = CNode.start_link(:player)
{[], %{state | cnode: cnode}}
end
@impl true
def handle_stream_format(:input, stream_format, ctx, state) do
%{input: input} = ctx.pads
%{cnode: cnode} = state
if !input.stream_format || stream_format == input.stream_format do
:ok = CNode.call(cnode, :create, [stream_format.width, stream_format.height])
{[], state}
else
raise "Stream format have changed while playing. This is not supported."
end
end
@impl true
def handle_start_of_stream(:input, ctx, state) do
use Ratio
{nom, denom} = ctx.pads.input.stream_format.framerate
timer = {:demand_timer, Time.seconds(denom) <|> nom}
{[demand: :input, start_timer: timer], %{state | timer_started?: true}}
end
@impl true
def handle_write(:input, %Buffer{payload: payload}, _ctx, state) do
payload = Membrane.Payload.to_binary(payload)
:ok = CNode.call(state.cnode, :display_frame, [payload])
{[], state}
end
@impl true
def handle_tick(:demand_timer, _ctx, state) do
{[demand: :input], state}
end
end