From e8be3d8da2144246e47738b29084ec712752eb78 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Mon, 27 May 2013 17:37:41 -0700
Subject: [PATCH 1/2] Decode VAG samples in one shot, not two.

---
 Core/HW/SasAudio.cpp | 15 ++++++++-------
 Core/HW/SasAudio.h   |  1 +
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/Core/HW/SasAudio.cpp b/Core/HW/SasAudio.cpp
index 144507f7ce..a3ad0f13f1 100644
--- a/Core/HW/SasAudio.cpp
+++ b/Core/HW/SasAudio.cpp
@@ -66,14 +66,9 @@ void VagDecoder::DecodeBlock(u8 *&readp) {
 	for (int i = 0; i < 28; i += 2) {
 		int d = *readp++;
 		int s = (short)((d & 0xf) << 12);
-		samples[i] = s >> shift_factor;
+		DecodeSample(i, s >> shift_factor, predict_nr);
 		s = (short)((d & 0xf0) << 8);
-		samples[i + 1] = s >> shift_factor;
-	}
-	for (int i = 0; i < 28; i++) {
-		samples[i] = (int) (samples[i] + ((s_1 * f[predict_nr][0] + s_2 * f[predict_nr][1]) >> 6));
-		s_2 = s_1;
-		s_1 = samples[i];
+		DecodeSample(i + 1, s >> shift_factor, predict_nr);
 	}
 	curSample = 0;
 	curBlock_++;
@@ -82,6 +77,12 @@ void VagDecoder::DecodeBlock(u8 *&readp) {
 	}
 }
 
+inline void VagDecoder::DecodeSample(int i, int sample, int predict_nr) {
+	samples[i] = (int) (sample + ((s_1 * f[predict_nr][0] + s_2 * f[predict_nr][1]) >> 6));
+	s_2 = s_1;
+	s_1 = samples[i];
+}
+
 void VagDecoder::GetSamples(s16 *outSamples, int numSamples) {
 	if (end_) {
 		memset(outSamples, 0, numSamples * sizeof(s16));
diff --git a/Core/HW/SasAudio.h b/Core/HW/SasAudio.h
index e39b84fcf6..5426edafd7 100644
--- a/Core/HW/SasAudio.h
+++ b/Core/HW/SasAudio.h
@@ -86,6 +86,7 @@ public:
 	void DoState(PointerWrap &p);
 
 private:
+	void DecodeSample(int i, int sample, int predict_nr);
 	int samples[28];
 	int curSample;
 

From 1107571af5f9eb0a6c550731cb97e132c8a1c2ba Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Mon, 27 May 2013 17:56:18 -0700
Subject: [PATCH 2/2] Don't cap predict_nr, just make the table bigger.

---
 Core/HW/SasAudio.cpp | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/Core/HW/SasAudio.cpp b/Core/HW/SasAudio.cpp
index a3ad0f13f1..459387112e 100644
--- a/Core/HW/SasAudio.cpp
+++ b/Core/HW/SasAudio.cpp
@@ -22,12 +22,26 @@
 
 // #define AUDIO_TO_FILE
 
-static const s8 f[5][2] =
-{ { 0, 0 },
-{	 60,	0 },
-{	115, -52 },
-{	 98, -55 },
-{	122, -60 } };
+static const s8 f[16][2] = {
+	{   0,   0 },
+	{  60,	 0 },
+	{ 115, -52 },
+	{  98, -55 },
+	{ 122, -60 },
+
+	// Padding to prevent overflow.
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+	{   0,   0 },
+};
 
 void VagDecoder::Start(u32 data, int vagSize, bool loopEnabled) {
 	loopEnabled_ = loopEnabled;
@@ -47,9 +61,6 @@ void VagDecoder::DecodeBlock(u8 *&readp) {
 	int predict_nr = *readp++;
 	int shift_factor = predict_nr & 0xf;
 	predict_nr >>= 4;
-	if (predict_nr >= sizeof(f) / sizeof(f[0])) {
-		predict_nr = 0;
-	}
 	int flags = *readp++;
 	if (flags == 7) {
 		end_ = true;