diff --git a/Core/HW/MediaEngine.cpp b/Core/HW/MediaEngine.cpp
index ebeb6e91d..ebd35bde9 100644
--- a/Core/HW/MediaEngine.cpp
+++ b/Core/HW/MediaEngine.cpp
@@ -281,7 +281,7 @@ bool MediaEngine::openContext() {
 		return false;
 
 	setVideoDim();
-	m_audioContext = new SimpleAudio(m_audioType);
+	m_audioContext = new SimpleAudio(m_audioType, 44100, 2);
 	m_isVideoEnd = false;
 	m_mpegheaderReadPos++;
 	av_seek_frame(m_pFormatCtx, m_videoStream, 0, 0);
@@ -862,7 +862,13 @@ int MediaEngine::getAudioSamples(u32 bufferPtr) {
 	}
 	int outbytes = 0;
 
-	if (m_audioContext != NULL) {
+	if (m_audioContext != nullptr) {
+		if (headerCode1 == 0x24) {
+			// This means mono audio - tell the decoder to expect it before the first frame.
+			// Note that it will always send us back stereo audio.
+			m_audioContext->SetChannels(1);
+		}
+
 		if (!m_audioContext->Decode(audioFrame, frameSize, buffer, &outbytes)) {
 			ERROR_LOG(ME, "Audio (%s) decode failed during video playback", GetCodecName(m_audioType));
 		}
@@ -871,17 +877,6 @@ int MediaEngine::getAudioSamples(u32 bufferPtr) {
 #endif
 	}
 
-	if (headerCode1 == 0x24) {
-		// it a mono atrac3plus, convert it to stereo
-		s16 *outbuf = (s16*)buffer;
-		s16 *inbuf = (s16*)buffer;
-		for (int i = 0x800 - 1; i >= 0; i--) {
-			s16 sample = inbuf[i];
-			outbuf[i * 2] = sample;
-			outbuf[i * 2 + 1] = sample;
-		}
-	}
-
 	return 0x2000;
 }
 
diff --git a/Core/HW/SimpleAudioDec.cpp b/Core/HW/SimpleAudioDec.cpp
index f8074f0e9..356c83e60 100644
--- a/Core/HW/SimpleAudioDec.cpp
+++ b/Core/HW/SimpleAudioDec.cpp
@@ -129,6 +129,21 @@ void SimpleAudio::SetExtraData(u8 *data, int size, int wav_bytes_per_packet) {
 #endif
 }
 
+void SimpleAudio::SetChannels(int channels) {
+	if (channels_ == channels) {
+		// Do nothing, already set.
+		return;
+	}
+
+	if (codecOpen_) {
+		ERROR_LOG(ME, "Codec already open, cannot change channels");
+	} else {
+		channels_ = channels;
+		codecCtx_->channels = channels_;
+		codecCtx_->channel_layout = channels_ == 2 ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
+	}
+}
+
 SimpleAudio::~SimpleAudio() {
 #ifdef USE_FFMPEG
 	swr_free(&swrCtx_);
diff --git a/Core/HW/SimpleAudioDec.h b/Core/HW/SimpleAudioDec.h
index 03826ca0c..22ec180a8 100644
--- a/Core/HW/SimpleAudioDec.h
+++ b/Core/HW/SimpleAudioDec.h
@@ -56,6 +56,8 @@ public:
 	// Not save stated, only used by UI.  Used for ATRAC3 (non+) files.
 	void SetExtraData(u8 *data, int size, int wav_bytes_per_packet);
 
+	void SetChannels(int channels);
+
 	// These two are only here because of save states.
 	int GetAudioType() const { return audioType; }
 	void SetResampleFrequency(int freq) { wanted_resample_freq = freq; }