controll the interpolation frac by the fifo size

2 files changed, 15 insertions, 3 deletions

diff --git a/Source/Core/AudioCommon/Mixer.cpp b/Source/Core/AudioCommon/Mixer.cpp
index dd1e7ed386..99c5a56176 100644
--- a/Source/Core/AudioCommon/Mixer.cpp
+++ b/Source/Core/AudioCommon/Mixer.cpp
@@ -44,12 +44,18 @@ unsigned int CMixer::Mix(short* samples, unsigned int numSamples)
 	u32 indexR = Common::AtomicLoad(m_indexR);
 	u32 indexW = Common::AtomicLoad(m_indexW);
 
+	float numLeft = ((indexW - indexR) & INDEX_MASK) / 2;
+	m_numLeftI = (numLeft + m_numLeftI*(CONTROL_AVG-1)) / CONTROL_AVG;
+	float offset = (m_numLeftI - LOW_WATERMARK) * CONTROL_FACTOR;
+	if(offset > MAX_FREQ_SHIFT) offset = MAX_FREQ_SHIFT;
+	if(offset < -MAX_FREQ_SHIFT) offset = -MAX_FREQ_SHIFT;
+
 	//render numleft sample pairs to samples[]
 	//advance indexR with sample position
 	//remember fractional offset
 
 	static u32 frac = 0;
-	const u32 ratio = (u32)( 65536.0f * (float)AudioInterface::GetAIDSampleRate() / (float)m_sampleRate );
+	const u32 ratio = (u32)( 65536.0f * (float)AudioInterface::GetAIDSampleRate() / (float)m_sampleRate + offset );
 
 	if(ratio > 0x10000)
 		ERROR_LOG(AUDIO, "ratio out of range");
diff --git a/Source/Core/AudioCommon/Mixer.h b/Source/Core/AudioCommon/Mixer.h
index e38a64b067..954aa7b99a 100644
--- a/Source/Core/AudioCommon/Mixer.h
+++ b/Source/Core/AudioCommon/Mixer.h
@@ -8,9 +8,13 @@
 #include "StdMutex.h"
 
 // 16 bit Stereo
-#define MAX_SAMPLES			(1024 * 8)
+#define MAX_SAMPLES			(1024 * 2) // 64ms
 #define INDEX_MASK			(MAX_SAMPLES * 2 - 1)
-#define RESERVED_SAMPLES	(256)
+
+#define LOW_WATERMARK			1280 // 40 ms
+#define MAX_FREQ_SHIFT			0x0100 // of 0x10000
+#define CONTROL_FACTOR			0.3 // in freq_shift per fifo size offset
+#define CONTROL_AVG			32
 
 class CMixer {
 
@@ -24,6 +28,7 @@ public:
 		, m_logAudio(0)
 		, m_indexW(0)
 		, m_indexR(0)
+		, m_numLeftI(0.0f)
 	{
 		// AyuanX: The internal (Core & DSP) sample rate is fixed at 32KHz
 		// So when AI/DAC sample rate differs than 32KHz, we have to do re-sampling
@@ -97,6 +102,7 @@ protected:
 	volatile u32 m_indexR;
 
 	std::mutex m_csMixing;
+	float m_numLeftI;
 
 	volatile float m_speed; // Current rate of the emulation (1.0 = 100% speed)
 private: