update hermite resampler to support dynamic rate control (fixes audio

blips), remove some asserts in APU.

readme.txt

@@ -36,7 +36,7 @@ Wii homebrew is WiiBrew (www.wiibrew.org).
 [4.3.8]
 
 * Updated core to 1.56 (with less accurate but faster Blargg audio core)
-* Improved audio synchronization - reduced crackling
+* Improved audio synchronization with dynamic rate control - fixes audio crackles
 * Added BS-X BIOS loading
 * Memory optimizations to free up more MEM1 for Snes9x
 * Disable multi pixel format support for a speed boost

source/snes9x/apu/SNES_SPC.cpp

@@ -493,7 +493,7 @@ int SNES_SPC::cpu_read( int addr, rel_time_t time )
 			}
 			else // 1%
 			{
-				//assert( reg + (r_t0out + 0xF0 - 0x10000) < 0x100 );
+				if( reg + (r_t0out + 0xF0 - 0x10000) < 0x100 )
 					result = cpu_read( reg + (r_t0out + 0xF0 - 0x10000), time );
 			}
 		}

source/snes9x/apu/SNES_SPC.h

@@ -286,19 +286,15 @@ private:
 #endif
 };
 
-#include <assert.h>
-
 inline int SNES_SPC::sample_count() const { return (m.extra_clocks >> 5) * 2; }
 
 inline int SNES_SPC::read_port( time_t t, int port )
 {
-	assert( (unsigned) port < port_count );
 	return run_until_( t ) [port];
 }
 
 inline void SNES_SPC::write_port( time_t t, int port, int data )
 {
-	assert( (unsigned) port < port_count );
 	run_until_( t ) [0x10 + port] = data;
 	m.ram.ram [0xF4 + port] = data;
 }

source/snes9x/apu/SNES_SPC_misc.cpp

@@ -292,8 +292,6 @@ void SNES_SPC::reset_buf()
 
 void SNES_SPC::set_output( sample_t* out, int size )
 {
-	require( (size & 1) == 0 ); // size must be even
-	
 	m.extra_clocks &= clocks_per_sample - 1;
 	if ( out )
 	{
@@ -352,7 +350,6 @@ void SNES_SPC::save_extra()
 
 blargg_err_t SNES_SPC::play( int count, sample_t* out )
 {
-	require( (count & 1) == 0 ); // must be even
 	if ( count )
 	{
 		set_output( out, count );

source/snes9x/apu/SPC_CPU.h

@@ -1204,8 +1204,6 @@ loop:
 		m.cpu_error = "SPC emulation error";
 		goto stop;
 	} // switch
-	
-	assert( 0 ); // catch any unhandled instructions
 }   
 out_of_time:
 	rel_time -= m.cycle_table [*pc]; // undo partial execution of opcode

source/snes9x/apu/SPC_DSP.cpp

@@ -74,7 +74,6 @@ static BOOST::uint8_t const initial_regs [SPC_DSP::register_count] =
 
 void SPC_DSP::set_output( sample_t* out, int size )
 {
-	require( (size & 1) == 0 ); // must be even
 	if ( !out )
 	{
 		out  = m.extra;
@@ -518,7 +517,6 @@ VOICE_CLOCK( V4 )
 		if ( (v->brr_offset += 2) >= brr_block_size )
 		{
 			// Start decoding next BRR block
-			assert( v->brr_offset == brr_block_size );
 			v->brr_addr = (v->brr_addr + brr_block_size) & 0xFFFF;
 			if ( m.t_brr_header & 1 )
 			{
@@ -804,8 +802,6 @@ PHASE(31)  V(V4,0)       V(V1,2)\
 
 void SPC_DSP::run( int clocks_remain )
 {
-	require( clocks_remain > 0 );
-	
 	int const phase = m.phase;
 	m.phase = (phase + clocks_remain) & 31;
 	switch ( phase )

source/snes9x/apu/apu.cpp

@@ -352,8 +352,6 @@ bool8 S9xMixSamples (uint8 *buffer, int sample_count)
                     for (int32 i = 0; i < sample_count; ++i)
                         *((int16*)(dest+(i * 2))) += *((int16*)(msu::resample_buffer+(i * 2)));
 				}
-				else // should never occur
-					assert(0);
 			}
 		}
 		else
@@ -394,8 +392,8 @@ int S9xGetSampleCount (void)
 #ifdef GEKKO
 void S9xIncreaseDynamicRateMultiplier ()
 {
-	if(spc::dynamic_rate_multiplier != 1.001) {
+	if(spc::dynamic_rate_multiplier != 1.005) {
-		spc::dynamic_rate_multiplier = 1.001;
+		spc::dynamic_rate_multiplier = 1.005;
 		UpdatePlaybackRate();
 	}
 }
@@ -415,13 +413,16 @@ void S9xFinalizeSamples (void)
 
 	if (!Settings.Mute)
 	{
+		if(!spc::sound_in_sync) {
+			S9xIncreaseDynamicRateMultiplier();
+		}
+
 		drop_current_msu1_samples = FALSE;
 
 		if (!spc::resampler->push((short *) spc::landing_buffer, spc_core->sample_count()))
 		{
 			/* We weren't able to process the entire buffer. Potential overrun. */
 			spc::sound_in_sync = FALSE;
-			S9xIncreaseDynamicRateMultiplier();
 			
 			if (Settings.SoundSync && !Settings.TurboMode)
 				return;
@@ -442,7 +443,6 @@ void S9xFinalizeSamples (void)
 		if (!drop_current_msu1_samples && !msu::resampler->push((short *)msu::landing_buffer, S9xMSU1Samples()))
 		{
 			// should not occur, msu buffer is larger and we drop msu samples if spc buffer overruns
-			assert(0);
 		}
 	}
 
@@ -451,10 +451,8 @@ void S9xFinalizeSamples (void)
 	else
 	if (spc::resampler->space_empty() >= spc::resampler->space_filled())
 		spc::sound_in_sync = TRUE;
-	else {
+	else
-		S9xIncreaseDynamicRateMultiplier ();
 		spc::sound_in_sync = FALSE;
-	}
 
 	if(spc::sound_in_sync) {
 		S9xResetDynamicRateMultiplier ();

source/snes9x/apu/blargg_common.h

@@ -58,7 +58,6 @@ public:
 	void clear() { void* p = begin_; begin_ = 0; size_ = 0; free( p ); }
 	T& operator [] ( size_t n ) const
 	{
-		assert( n <= size_ ); // <= to allow past-the-end value
 		return begin_ [n];
 	}
 };

source/snes9x/apu/blargg_endian.h

@@ -57,10 +57,8 @@ inline void blargg_verify_byte_order()
 	#ifndef NDEBUG
 		#if BLARGG_BIG_ENDIAN
 			volatile int i = 1;
-			assert( *(volatile char*) &i == 0 );
 		#elif BLARGG_LITTLE_ENDIAN
 			volatile int i = 1;
-			assert( *(volatile char*) &i != 0 );
 		#endif
 	#endif
 }

source/snes9x/apu/hermite_resampler.h

@@ -14,25 +14,20 @@ class HermiteResampler : public Resampler
 {
     protected:
 
-        double r_step;
+        float r_step;
-        double r_frac;
+        float r_frac;
         int   r_left[4], r_right[4];
 
-        double
+        static inline float
-        hermite (double mu1, double a, double b, double c, double d)
+        hermite (float mu1, float a, float b, float c, float d)
         {
-            const double tension = 0.0; //-1 = low, 0 = normal, 1 = high
+            float mu2, mu3, m0, m1, a0, a1, a2, a3;
-            const double bias    = 0.0; //-1 = left, 0 = even, 1 = right
-
-            double mu2, mu3, m0, m1, a0, a1, a2, a3;
 
             mu2 = mu1 * mu1;
             mu3 = mu2 * mu1;
 
-            m0  = (b - a) * (1 + bias) * (1 - tension) / 2;
+            m0 = (c - a) * 0.5;
-            m0 += (c - b) * (1 - bias) * (1 - tension) / 2;
+            m1 = (d - b) * 0.5;
-            m1  = (c - b) * (1 + bias) * (1 - tension) / 2;
-            m1 += (d - c) * (1 - bias) * (1 - tension) / 2;
 
             a0 = +2 * mu3 - 3 * mu2 + 1;
             a1 =      mu3 - 2 * mu2 + mu1;
@@ -56,7 +51,6 @@ class HermiteResampler : public Resampler
         time_ratio (double ratio)
         {
             r_step = ratio;
-            clear ();
         }
 
         void
@@ -71,7 +65,15 @@ class HermiteResampler : public Resampler
         void
         read (short *data, int num_samples)
         {
+            //If we are outputting the exact same ratio as the input, pull directly from the input buffer
+            if (r_step == 1.0)
+            {
+                ring_buffer::pull((unsigned char*)data, num_samples * sizeof(short));
+                return;
+            }
+
             int i_position = start >> 1;
+            int max_samples = buffer_size >> 1;
             short *internal_buffer = (short *) buffer;
             int o_position = 0;
             int consumed = 0;
@@ -80,27 +82,14 @@ class HermiteResampler : public Resampler
             {
                 int s_left = internal_buffer[i_position];
                 int s_right = internal_buffer[i_position + 1];
-                int max_samples = buffer_size >> 1;
+                float hermite_val[2];
-                const double margin_of_error = 1.0e-10;
-
-                if (fabs(r_step - 1.0) < margin_of_error)
-                {
-                    data[o_position] = (short) s_left;
-                    data[o_position + 1] = (short) s_right;
-
-                    o_position += 2;
-                    i_position += 2;
-                    if (i_position >= max_samples)
-                        i_position -= max_samples;
-                    consumed += 2;
-
-                    continue;
-                }
 
                 while (r_frac <= 1.0 && o_position < num_samples)
                 {
-                    data[o_position]     = SHORT_CLAMP (hermite (r_frac, r_left [0], r_left [1], r_left [2], r_left [3]));
+                    hermite_val[0] = hermite (r_frac, r_left [0], r_left [1], r_left [2], r_left [3]);
-                    data[o_position + 1] = SHORT_CLAMP (hermite (r_frac, r_right[0], r_right[1], r_right[2], r_right[3]));
+                    hermite_val[1] = hermite (r_frac, r_right[0], r_right[1], r_right[2], r_right[3]);
+                    data[o_position]     = SHORT_CLAMP (hermite_val[0]);
+                    data[o_position + 1] = SHORT_CLAMP (hermite_val[1]);
 
                     o_position += 2;
 
@@ -137,6 +126,12 @@ class HermiteResampler : public Resampler
         inline int
         avail (void)
         {
+            //If we are outputting the exact same ratio as the input, find out directly from the input buffer
+            if (r_step == 1.0)
+            {
+                return (ring_buffer::space_filled() + sizeof(short) - 1) / sizeof(short);
+            }
+
             return (int) floor (((size >> 2) - r_frac) / r_step) * 2;
         }
 };

source/snes9x/apu/resampler.h

@@ -33,19 +33,19 @@ class Resampler : public ring_buffer
         }
 
         inline int
-        space_empty (void)
+        space_empty (void) const
         {
             return buffer_size - size;
         }
 
         inline int
-        space_filled (void)
+        space_filled (void) const
         {
             return size;
         }
 
         inline int
-        max_write (void)
+        max_write (void) const
         {
             return space_empty () >> 1;
         }

source/snes9x/apu/ring_buffer.h

@@ -69,13 +69,13 @@ public:
     }
 
     inline int
-    space_empty (void)
+    space_empty (void) const
     {
         return buffer_size - size;
     }
 
     inline int
-    space_filled (void)
+    space_filled (void) const
     {
         return size;
     }
@@ -96,7 +96,7 @@ public:
         buffer = new unsigned char[buffer_size];
         memset (buffer, 0, this->buffer_size);
 
-        size = 0;
+        this->size = 0;
         start = 0;
     }