fix(voip-mumble): nullptr check

This fixes a nullptr exception when trying to write to the Audio Processing Module while the audioCaptureClient is invalid.

We now also apply the last voice intent mode to the new audio device instead of the default ('speech') mode.

code/components/voip-mumble/src/MumbleAudioInput.cpp

@@ -139,22 +139,26 @@ void MumbleAudioInput::ThreadFunc()
 
 		if (g_curInputIntentMode != g_lastIntentMode)
 		{
-			switch (g_curInputIntentMode)
-			{
-			case InputIntentMode::MUSIC:
-			{
-				m_apm->noise_suppression()->Enable(false);
-				m_apm->high_pass_filter()->Enable(false);
-				break;
-			}
-			case InputIntentMode::SPEECH:
-			default:
+			if (m_apm)
 			{
-				m_apm->noise_suppression()->Enable(true);
-				m_apm->high_pass_filter()->Enable(true);
-				break;
+				switch (g_curInputIntentMode)
+				{
+				case InputIntentMode::MUSIC:
+				{
+					m_apm->noise_suppression()->Enable(false);
+					m_apm->high_pass_filter()->Enable(false);
+					break;
+				}
+				case InputIntentMode::SPEECH:
+				default:
+				{
+					m_apm->noise_suppression()->Enable(true);
+					m_apm->high_pass_filter()->Enable(true);
+					break;
+				}
+				};
 			}
-			};
+
 			g_lastIntentMode = g_curInputIntentMode;
 		}
 
@@ -705,10 +709,12 @@ void MumbleAudioInput::InitializeAudioDevice()
 
 	m_apm->Initialize(pconfig);
 
-	m_apm->high_pass_filter()->Enable(true);
-	m_apm->echo_cancellation()->Enable(false);
-	m_apm->noise_suppression()->Enable(true);
+	const bool isVoiceIntent = g_curInputIntentMode == InputIntentMode::SPEECH;
+	m_apm->high_pass_filter()->Enable(isVoiceIntent);
+	m_apm->noise_suppression()->Enable(isVoiceIntent);
 	m_apm->noise_suppression()->set_level(webrtc::NoiseSuppression::kHigh);
+
+	m_apm->echo_cancellation()->Enable(false);
 	m_apm->level_estimator()->Enable(true);
 	m_apm->voice_detection()->set_likelihood(ConvertLikelihood(m_likelihood));
 	//m_apm->voice_detection()->set_frame_size_ms(10);