Added tehpola's latest changes to gc_audio/main.c with some commented dumping functions, and also re-added the 50% volume decrease into the RSP.. it actually does sound better on some games

gc_audio/audio.c

@@ -3,7 +3,7 @@
    ----------------------------------------------------
    MEMORY USAGE:
      STATIC:
-   	Audio Buffer: 2x BUFFER_SIZE (currently 4kb each)
+   	Audio Buffer: 4x BUFFER_SIZE (currently ~3kb each)
  */
 
 #include "../main/winlnxdefs.h"
@@ -17,6 +17,13 @@
 #include <ogc/semaphore.h>
 #endif
 
+//#define DUMP_AUDIO 1
+#ifdef DUMP_AUDIO
+#include "../main/rom.h"
+#include <fat.h>
+FILE* dump_audio_fp;
+#endif
+
 #include "AudioPlugin.h"
 #include "Audio_#1.1.h"
 #include "../gui/DEBUG.h"
@@ -24,11 +31,17 @@
 AUDIO_INFO AudioInfo;
 
 #define NUM_BUFFERS 4
-#define BUFFER_SIZE 2*1024
+#define BUFFER_SIZE 3840/2
 static char buffer[NUM_BUFFERS][BUFFER_SIZE] __attribute__((aligned(32)));
 static int which_buffer = 0;
 static unsigned int buffer_offset = 0;
 #define NEXT(x) (x=(x+1)%NUM_BUFFERS)
+static unsigned int freq;
+static unsigned int real_freq;
+static float freq_ratio;
+// NOTE: 32khz actually uses ~2136 bytes/frame @ 60hz
+static enum { BUFFER_SIZE_32_60 = 2176/2, BUFFER_SIZE_48_60 = 3200/2,
+              BUFFER_SIZE_32_50 = 2560/2, BUFFER_SIZE_48_50 = 3840/2 } buffer_size;
 
 #ifdef THREADED_AUDIO
 static lwp_t audio_thread;
@@ -51,27 +64,48 @@ EXPORT void CALL
 AiDacrateChanged( int SystemType )
 {
 	// Taken from mupen_audio
-	int f = 32000; //default to 32khz incase we get a bad systemtype
+	freq = 32000; //default to 32khz incase we get a bad systemtype
 	switch (SystemType){
 	      case SYSTEM_NTSC:
-		f = 48681812 / (*AudioInfo.AI_DACRATE_REG + 1);
+		freq = 48681812 / (*AudioInfo.AI_DACRATE_REG + 1);
 		break;
 	      case SYSTEM_PAL:
-		f = 49656530 / (*AudioInfo.AI_DACRATE_REG + 1);
+		freq = 49656530 / (*AudioInfo.AI_DACRATE_REG + 1);
 		break;
 	      case SYSTEM_MPAL:
-		f = 48628316 / (*AudioInfo.AI_DACRATE_REG + 1);
+		freq = 48628316 / (*AudioInfo.AI_DACRATE_REG + 1);
 		break;
 	}
 	
-	if      ( f == 32000 )
+	// Calculate the absolute differences from 32 and 48khz
+	int diff32 = freq - 32000;
+	int diff48 = freq - 48000;
+	diff32 = diff32 > 0 ? diff32 : -diff32;
+	diff48 = diff48 > 0 ? diff48 : -diff48;
+	// Choose the closest real frequency
+	real_freq = (diff32 < diff48) ? 32000 : 48000;
+	freq_ratio = (float)freq / real_freq;
+	
+	if( real_freq == 32000 ){
 		AUDIO_SetDSPSampleRate(AI_SAMPLERATE_32KHZ);
-	else if ( f == 48000 )
+		buffer_size = (SystemType != SYSTEM_PAL) ?
+		               BUFFER_SIZE_32_60 : BUFFER_SIZE_32_50;
+	} else if( real_freq == 48000 ){
 		AUDIO_SetDSPSampleRate(AI_SAMPLERATE_48KHZ);
-	else {
-		 sprintf(txtbuffer,"error initializing frequency: %d", f);
-	   	 DEBUG_print(txtbuffer,DBG_AUDIOINFO); 
+		buffer_size = (SystemType != SYSTEM_PAL) ?
+		               BUFFER_SIZE_48_60 : BUFFER_SIZE_48_50;
 	}
+	
+	sprintf(txtbuffer, "Initializing frequency: %d (resampling ratio %f)",
+	        real_freq, freq_ratio);
+	DEBUG_print(txtbuffer,DBG_AUDIOINFO);
+	#ifdef DUMP_AUDIO
+  char tmpname[256];
+  memset(tmpname,0,256);
+  sprintf(tmpname,"/AUDIO/%d - %s.pcm",real_freq,ROM_SETTINGS.goodname);
+  if(!dump_audio_fp)
+    dump_audio_fp = fopen(tmpname,"wb");
+#endif
 }
 
 #ifdef THREADED_AUDIO
@@ -92,42 +126,74 @@ static void inline play_buffer(void){
 	// This thread will keep giving buffers to the audio as they come
 	while(thread_running){
 	
-	// Wait for a buffer to be processed and the audio to be ready
+	// Wait for a buffer to be processed
 	LWP_SemWait(buffer_full);
+#endif
+	
+	// Make sure the buffer is in RAM, not the cache
+	DCFlushRange(buffer[thread_buffer], buffer_size);
+	
+#ifdef THREADED_AUDIO
+	// Wait for the audio interface to be free before playing
 	LWP_SemWait(audio_free);
 #endif
 	
-	DCFlushRange (buffer[thread_buffer], BUFFER_SIZE);
-	AUDIO_InitDMA((unsigned int)&buffer[thread_buffer], BUFFER_SIZE);
+	// Actually send the buffer out to be played
+	AUDIO_InitDMA((unsigned int)&buffer[thread_buffer], buffer_size);
 	AUDIO_StartDMA();
+	
 #ifdef THREADED_AUDIO
+	// Move the index to the next buffer
 	NEXT(thread_buffer);
 	}
 #endif
 }
 
-static void inline copy_to_buffer(char* buffer, char* stream, unsigned int length){
-	memcpy(buffer, stream, length);
+static void inline copy_to_buffer(int* buffer, int* stream, unsigned int length){
+	// NOTE: length is in samples (stereo (2) shorts)
+	int di;
+	float si;
+	for(di = 0, si = 0.0f; di < length; ++di, si += freq_ratio){
+#if 1
+		// Linear interpolation between current and next sample
+		float t = si - floorf(si);
+		short* osample  = (short*)(buffer + di);
+		short* isample1 = (short*)(stream + (int)si);
+		short* isample2 = (short*)(stream + (int)ceilf(si));
+		// Left and right
+		osample[0] = (1.0f - t)*isample1[0] + t*isample2[0];
+		osample[1] = (1.0f - t)*isample1[1] + t*isample2[1];
+#else
+		// Quick and dirty resampling: skip over or repeat samples
+		buffer[di] = stream[(int)si];
+#endif
+	}
+#ifdef DUMP_AUDIO
+	fwrite(buffer, 1, length*4, dump_audio_fp);
+#endif
 }
 
 static void inline add_to_buffer(void* stream, unsigned int length){
 	// This shouldn't lose any data and works for any size
-	unsigned int lengthi;
-	unsigned int lengthLeft = length;
 	unsigned int stream_offset = 0;
+	// Length calculations are in samples (stereo (short) sample pairs)
+	unsigned int lengthi, rlengthi;
+	unsigned int lengthLeft = length >> 2;
+	unsigned int rlengthLeft = ceilf(lengthLeft / freq_ratio);
 	while(1){
-		lengthi = (buffer_offset + lengthLeft < BUFFER_SIZE) ?
-		           lengthLeft : (BUFFER_SIZE - buffer_offset);
+		rlengthi = (buffer_offset + (rlengthLeft << 2) < buffer_size) ?
+		            rlengthLeft : ((buffer_size - buffer_offset) >> 2);
+		lengthi  = rlengthi * freq_ratio;
 	
 #ifdef THREADED_AUDIO
 		// Wait for a buffer we can copy into
 		LWP_SemWait(buffer_empty);
 #endif		
 		copy_to_buffer(buffer[which_buffer] + buffer_offset,
-		               stream + stream_offset, lengthi);
+		               stream + stream_offset, rlengthi);
 		
-		if(buffer_offset + lengthLeft < BUFFER_SIZE){
-			buffer_offset += lengthi;
+		if(buffer_offset + (rlengthLeft << 2) < buffer_size){
+			buffer_offset += rlengthi << 2;
 #ifdef THREADED_AUDIO
 			// This is a little weird, but we didn't fill this buffer.
 			//   So it is still considered 'empty', but since we 'decremented'
@@ -139,7 +205,8 @@ static void inline add_to_buffer(void* stream, unsigned int length){
 		}
 		
 		lengthLeft    -= lengthi;
-		stream_offset += lengthi;
+		stream_offset += lengthi << 2;
+		rlengthLeft   -= rlengthi;
 		
 #ifdef THREADED_AUDIO
 		// Let the audio thread know that we've filled a new buffer
@@ -245,6 +312,11 @@ RomClosed( void )
 	audio_paused = 0;
 #endif
 	AUDIO_StopDMA(); // So we don't have a buzzing sound when we exit the game
+	#ifdef DUMP_AUDIO
+  if(dump_audio_fp)
+    fclose(dump_audio_fp);
+  dump_audio_fp = 0;
+#endif
 }
 
 EXPORT void CALL

rsp_hle-ppc/ucode1.c

@@ -135,13 +135,10 @@ static void adpcm_block(short *out,int src)
    mul2>>=2;
    downshift-=2;
    
- /*  if(1)
-     {
-        // decrease volume to 50%
-        mul2*=2;
-        mul1*=2;
-        downshift+=1;
-     }*/
+   // decrease volume to 50%
+   mul2*=2;
+   mul1*=2;
+   downshift+=1;
    
    // init tmp buffer with last block
    last2=last[14];

rsp_hle-ppc/ucode2.c

@@ -112,6 +112,11 @@ static void adpcm_block(short *out,int src)
    mul2>>=2;
    downshift-=2;
    
+   // decrease volume to 50%
+   mul2*=2;
+   mul1*=2;
+   downshift+=1;
+   
    // init tmp buffer with last block
    last2=last[14];
    last1=last[15];

rsp_hle-ppc/ucode3.c

@@ -125,6 +125,10 @@ static void adpcm_block(short *out,int src, int bits)
    mul2>>=2;
    downshift-=2;
    
+   // decrease volume to 50%
+   mul2*=2;
+   mul1*=2;
+   downshift+=1;
   
    // init tmp buffer with last block
    last2=last[14];