Merge pull request #41 from membraneframework/fix/live-silence-proces…

…sing

Fix handling silence

README.md

@@ -13,7 +13,7 @@ It is a part of [Membrane Multimedia Framework](https://membraneframework.org).
 Add the following line to your `deps` in `mix.exs`. Run `mix deps.get`.
 
 ```elixir
-{:membrane_audio_mix_plugin, "~> 0.15.1"}
+{:membrane_audio_mix_plugin, "~> 0.15.2"}
 ```
 
 ## Description

lib/membrane_audio_mixer/clip_preventing_adder.ex

@@ -57,29 +57,22 @@ defmodule Membrane.AudioMixer.ClipPreventingAdder do
     split_fun = if state.is_wave_positive, do: &(&1 >= 0), else: &(&1 <= 0)
     {values, rest} = Enum.split_while(values, split_fun)
 
-    silence? = Enum.all?(values, fn value -> value == 0 end)
+    if rest != [] or is_last_wave do
+      buffer = [buffer | get_iodata(values, state)] |> IO.iodata_to_binary()
 
-    cond do
-      rest != [] or is_last_wave ->
-        buffer = [buffer | get_iodata(values, state)] |> IO.iodata_to_binary()
-
-        state =
-          state
-          |> Map.put(:is_wave_positive, !state.is_wave_positive)
-          |> Map.put(:queue, [])
-
-        if is_last_wave && rest == [] do
-          {buffer, state}
-        else
-          add_values(rest, is_last_wave, state, buffer)
-        end
+      state =
+        state
+        |> Map.put(:is_wave_positive, !state.is_wave_positive)
+        |> Map.put(:queue, [])
 
-      silence? ->
-        {values_to_raw_sample(values, state.stream_format), state}
-
-      true ->
-        state = %__MODULE__{state | queue: state.queue ++ values}
+      if rest == [] do
         {buffer, state}
+      else
+        add_values(rest, is_last_wave, state, buffer)
+      end
+    else
+      state = %__MODULE__{state | queue: state.queue ++ values}
+      {buffer, state}
     end
   end
 
@@ -104,10 +97,4 @@ defmodule Membrane.AudioMixer.ClipPreventingAdder do
   end
 
   defp do_scale(values, coefficient), do: Enum.map(values, &trunc(&1 * coefficient))
-
-  defp values_to_raw_sample(values, stream_format) do
-    values
-    |> Enum.map(fn value -> RawAudio.value_to_sample(value, stream_format) end)
-    |> IO.iodata_to_binary()
-  end
 end

lib/membrane_live_audio_mixer.ex

@@ -40,7 +40,7 @@ defmodule Membrane.LiveAudioMixer do
                 - If false, overflow will be clipped to the maximal value of the sample in
                 the format. See `Membrane.AudioMixer.Adder`.
                 """,
-                default: true
+                default: false
               ],
               native_mixer: [
                 spec: boolean(),
@@ -101,6 +101,15 @@ defmodule Membrane.LiveAudioMixer do
 
   @impl true
   def handle_init(_ctx, options) do
+    # TODO: native and prevent_clipping adder enqueue silence.
+    # in live mixer we want to immediately return added audio
+    if options.native_mixer or options.prevent_clipping do
+      Membrane.Logger.warn("""
+      Leaving options prevent_clipping and native_mixer as defaults is recommended.
+      In other case silence will be enqueued by mixer and send only when there will be some sound"
+      """)
+    end
+
     cond do
       options.native_mixer && !options.prevent_clipping ->
         raise "Invalid element options, for native mixer only clipping preventing one is available"
@@ -231,7 +240,11 @@ defmodule Membrane.LiveAudioMixer do
         {[], payload, state}
       end
 
-    {[buffer: {:output, %Buffer{payload: payload}}] ++ actions, state}
+    if payload == <<>> do
+      {actions, state}
+    else
+      {[buffer: {:output, %Buffer{payload: payload}}] ++ actions, state}
+    end
   end
 
   @impl true

mix.exs

@@ -1,7 +1,7 @@
 defmodule Membrane.AudioMix.Mixfile do
   use Mix.Project
 
-  @version "0.15.1"
+  @version "0.15.2"
   @github_url "https://github.com/membraneframework/membrane_audio_mix_plugin"
 
   def project do