Add extra latency to microphone playback to reduce clipping.

servers/audio/audio_stream.cpp

@@ -138,7 +138,7 @@ void AudioStreamPlaybackMicrophone::_mix_internal(AudioFrame *p_buffer, int p_fr
 	unsigned int input_size = AudioDriver::get_singleton()->get_input_size();
 
 	// p_frames is multipled by two since an AudioFrame is stereo
-	if ((p_frames * 2) > input_size) {
+	if ((p_frames + MICROPHONE_PLAYBACK_DELAY * 2) > input_size) {
 		for (int i = 0; i < p_frames; i++) {
 			p_buffer[i] = AudioFrame(0.0f, 0.0f);
 		}

servers/audio/audio_stream.h

@@ -122,6 +122,8 @@ class AudioStreamPlaybackMicrophone : public AudioStreamPlaybackResampled {
 	GDCLASS(AudioStreamPlaybackMicrophone, AudioStreamPlayback)
 	friend class AudioStreamMicrophone;
 
+	const int MICROPHONE_PLAYBACK_DELAY = 256;
+
 	bool active;
 	unsigned int input_ofs;