Convert audio to 8kHz before feeding it to WebRTC for VAC

This prevents false positives at the beginning of the audio stream. Fixes issue #52.

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 * **Added** basic support for non-English recordings through phonetic recognition ([issue #45](https://github.com/DanielSWolf/rhubarb-lip-sync/issues/45)).
+* **Fixed** a bug that resulted in unwanted mouth movement at beginning of a recording ([issue #53](https://github.com/DanielSWolf/rhubarb-lip-sync/issues/53)).
 * **Fixed** a bug that prevented the progress bar from reaching 100% ([issue #48](https://github.com/DanielSWolf/rhubarb-lip-sync/issues/48)).
 
 ## Version 1.8.0

rhubarb/src/audio/voiceActivityDetection.cpp

@@ -83,7 +83,7 @@ JoiningBoundedTimeline<void> detectVoiceActivity(
 ) {
 	// Prepare audio for VAD
 	const unique_ptr<AudioClip> audioClip = inputAudioClip.clone()
-		| resample(16000)
+		| resample(8000) // Convert to the internal sampling rate of WebRTC
 		| removeDcOffset();
 
 	JoiningBoundedTimeline<void> activity(audioClip->getTruncatedRange());