src/audio/nto/SDL_nto_audio.c
changeset 718 cbc0f7fabd1c
parent 663 8bedd6d61642
child 769 b8d311d90021
--- a/src/audio/nto/SDL_nto_audio.c	Mon Sep 15 13:51:25 2003 +0000
+++ b/src/audio/nto/SDL_nto_audio.c	Sun Sep 21 18:13:48 2003 +0000
@@ -30,8 +30,9 @@
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sched.h>
+#include <sys/select.h>
+#include <sys/neutrino.h>
 #include <sys/asoundlib.h>
-#include <sys/select.h>
 
 #include "SDL_audio.h"
 #include "SDL_error.h"
@@ -41,11 +42,12 @@
 #include "SDL_nto_audio.h"
 
 /* The tag name used by NTO audio */
-#define DRIVER_NAME         "nto"
+#define DRIVER_NAME "qsa-nto"
 
 /* default channel communication parameters */
 #define DEFAULT_CPARAMS_RATE 22050
 #define DEFAULT_CPARAMS_VOICES 1
+/* FIXME: need to add in the near future flexible logic with frag_size and frags count */
 #define DEFAULT_CPARAMS_FRAG_SIZE 4096
 #define DEFAULT_CPARAMS_FRAGS_MIN 1
 #define DEFAULT_CPARAMS_FRAGS_MAX 1
@@ -53,438 +55,456 @@
 /* Open the audio device for playback, and don't block if busy */
 #define OPEN_FLAGS SND_PCM_OPEN_PLAYBACK
 
+#define QSA_NO_WORKAROUNDS  0x00000000
+#define QSA_MMAP_WORKAROUND 0x00000001
+
+struct BuggyCards
+{
+   char* cardname;
+   unsigned long bugtype;
+};
+
+#define QSA_WA_CARDS 3
+
+struct BuggyCards buggycards[QSA_WA_CARDS]=
+{
+   {"Sound Blaster Live!", QSA_MMAP_WORKAROUND},
+   {"Vortex 8820",         QSA_MMAP_WORKAROUND},
+   {"Vortex 8830",         QSA_MMAP_WORKAROUND},
+};
+
 /* Audio driver functions */
-static int NTO_OpenAudio(_THIS, SDL_AudioSpec *spec);
+static void NTO_ThreadInit(_THIS);
+static int NTO_OpenAudio(_THIS, SDL_AudioSpec* spec);
 static void NTO_WaitAudio(_THIS);
 static void NTO_PlayAudio(_THIS);
-static Uint8 *NTO_GetAudioBuf(_THIS);
+static Uint8* NTO_GetAudioBuf(_THIS);
 static void NTO_CloseAudio(_THIS);
 
-static snd_pcm_channel_status_t cstatus;
-static snd_pcm_channel_params_t cparams;
-static snd_pcm_channel_setup_t  csetup;
+/* card names check to apply the workarounds */
+static int NTO_CheckBuggyCards(_THIS, unsigned long checkfor)
+{
+    char scardname[33];
+    int it;
+    
+    if (snd_card_get_name(cardno, scardname, 32)<0)
+    {
+        return 0;
+    }
+
+    for (it=0; it<QSA_WA_CARDS; it++)
+    {
+       if (strcmp(buggycards[it].cardname, scardname)==0)
+       {
+          if (buggycards[it].bugtype==checkfor)
+          {
+              return 1;
+          }
+       }
+    }
+
+    return 0;
+}
+
+static void NTO_ThreadInit(_THIS)
+{
+   int status;
+   struct sched_param param;
+
+   /* increasing default 10 priority to 25 to avoid jerky sound */
+   status=SchedGet(0, 0, &param);
+   param.sched_priority=param.sched_curpriority+15;
+   status=SchedSet(0, 0, SCHED_NOCHANGE, &param);
+}
 
 /* PCM transfer channel parameters initialize function */
-static void init_pcm_cparams(snd_pcm_channel_params_t* cparams)
+static void NTO_InitAudioParams(snd_pcm_channel_params_t* cpars)
 {
-	memset(cparams,0,sizeof(snd_pcm_channel_params_t));
+    memset(cpars, 0, sizeof(snd_pcm_channel_params_t));
 
-	cparams->channel = SND_PCM_CHANNEL_PLAYBACK;
-	cparams->mode = SND_PCM_MODE_BLOCK;
-	cparams->start_mode = SND_PCM_START_DATA;
-	cparams->stop_mode  = SND_PCM_STOP_STOP;
-	cparams->format.format = SND_PCM_SFMT_S16_LE;
-	cparams->format.interleave = 1;
-	cparams->format.rate = DEFAULT_CPARAMS_RATE;
-	cparams->format.voices = DEFAULT_CPARAMS_VOICES;
-	cparams->buf.block.frag_size = DEFAULT_CPARAMS_FRAG_SIZE;
-	cparams->buf.block.frags_min = DEFAULT_CPARAMS_FRAGS_MIN;
-	cparams->buf.block.frags_max = DEFAULT_CPARAMS_FRAGS_MAX;
+    cpars->channel = SND_PCM_CHANNEL_PLAYBACK;
+    cpars->mode = SND_PCM_MODE_BLOCK;
+    cpars->start_mode = SND_PCM_START_DATA;
+    cpars->stop_mode  = SND_PCM_STOP_STOP;
+    cpars->format.format = SND_PCM_SFMT_S16_LE;
+    cpars->format.interleave = 1;
+    cpars->format.rate = DEFAULT_CPARAMS_RATE;
+    cpars->format.voices = DEFAULT_CPARAMS_VOICES;
+    cpars->buf.block.frag_size = DEFAULT_CPARAMS_FRAG_SIZE;
+    cpars->buf.block.frags_min = DEFAULT_CPARAMS_FRAGS_MIN;
+    cpars->buf.block.frags_max = DEFAULT_CPARAMS_FRAGS_MAX;
 }
 
-static int Audio_Available(void)
+static int NTO_AudioAvailable(void)
 {
-	/*
-		See if we can open a nonblocking channel.
-		Return value '1' means we can.
-		Return value '0' means we cannot.
-	*/
+    /*  See if we can open a nonblocking channel.
+        Return value '1' means we can.
+        Return value '0' means we cannot. */
 
-	int available;
-	int rval;
-	snd_pcm_t *handle;
+    int available;
+    int rval;
+    snd_pcm_t* handle;
 
-	available = 0;
-	handle = NULL;
+    available = 0;
+    handle = NULL;
 
-	rval = snd_pcm_open_preferred(&handle, NULL, NULL, OPEN_FLAGS);
+    rval = snd_pcm_open_preferred(&handle, NULL, NULL, OPEN_FLAGS);
 
-	if (rval >= 0){
-		available = 1;
-		
-		if ((rval = snd_pcm_close(handle)) < 0){
-			SDL_SetError("snd_pcm_close failed: %s\n",snd_strerror(rval));
-			available = 0;
-		}
-	}
-	else{
-		SDL_SetError("snd_pcm_open failed: %s\n", snd_strerror(rval));
-	}
-	
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"AudioAvailable rtns %d\n", available);
-	#endif
-	
-	return(available);
+    if (rval >= 0)
+    {
+        available = 1;
+
+        if ((rval = snd_pcm_close(handle)) < 0)
+        {
+            SDL_SetError("NTO_AudioAvailable(): snd_pcm_close failed: %s\n", snd_strerror(rval));
+            available = 0;
+        }
+    }
+    else
+    {
+        SDL_SetError("NTO_AudioAvailable(): there are no available audio devices.\n");
+    }
+
+    return (available);
 }
 
-static void Audio_DeleteDevice(SDL_AudioDevice *device)
+static void NTO_DeleteAudioDevice(SDL_AudioDevice *device)
 {
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"Audio_DeleteDevice\n");
-	#endif
-
-	free(device->hidden);
-	free(device);
+    if ((device)&&(device->hidden))
+    {
+        free(device->hidden);
+    }
+    if (device)
+    {
+        free(device);
+    }
 }
 
-static SDL_AudioDevice *Audio_CreateDevice(int devindex)
+static SDL_AudioDevice* NTO_CreateAudioDevice(int devindex)
 {
-	SDL_AudioDevice *this;
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"Audio_CreateDevice\n");
-	#endif
-	/* Initialize all variables that we clean on shutdown */
-	this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
-	if ( this ) {
-		memset(this, 0, (sizeof *this));
-		this->hidden = (struct SDL_PrivateAudioData *)
-		malloc((sizeof *this->hidden));
+    SDL_AudioDevice *this;
+
+    /* Initialize all variables that we clean on shutdown */
+    this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
+    if (this)
+    {
+        memset(this, 0, sizeof(SDL_AudioDevice));
+        this->hidden = (struct SDL_PrivateAudioData *)malloc(sizeof(struct SDL_PrivateAudioData));
+    }
+    if ((this == NULL) || (this->hidden == NULL))
+    {
+        SDL_OutOfMemory();
+        if (this)
+        {
+            free(this);
 	}
-	if ( (this == NULL) || (this->hidden == NULL) ) {
-		SDL_OutOfMemory();
-		if ( this ) {
-			free(this);
-		}
-		return(0);
-	}
-	memset(this->hidden, 0, (sizeof *this->hidden));
-	audio_handle = NULL;
+        return (0);
+    }
+    memset(this->hidden, 0, sizeof(struct SDL_PrivateAudioData));
+    audio_handle = NULL;
 
-	/* Set the function pointers */
-	this->OpenAudio = NTO_OpenAudio;
-	this->WaitAudio = NTO_WaitAudio;
-	this->PlayAudio = NTO_PlayAudio;
-	this->GetAudioBuf = NTO_GetAudioBuf;
-	this->CloseAudio = NTO_CloseAudio;
+    /* Set the function pointers */
+    this->ThreadInit = NTO_ThreadInit;
+    this->OpenAudio = NTO_OpenAudio;
+    this->WaitAudio = NTO_WaitAudio;
+    this->PlayAudio = NTO_PlayAudio;
+    this->GetAudioBuf = NTO_GetAudioBuf;
+    this->CloseAudio = NTO_CloseAudio;
 
-	this->free = Audio_DeleteDevice;
+    this->free = NTO_DeleteAudioDevice;
 
-	return this;
+    return this;
 }
 
-AudioBootStrap QNXNTOAUDIO_bootstrap = {
-	DRIVER_NAME, "QNX6 NTO PCM audio",
-	Audio_Available, Audio_CreateDevice
+AudioBootStrap QNXNTOAUDIO_bootstrap =
+{
+    DRIVER_NAME, "QNX6 QSA-NTO Audio",
+    NTO_AudioAvailable,
+    NTO_CreateAudioDevice
 };
 
 /* This function waits until it is possible to write a full sound buffer */
 static void NTO_WaitAudio(_THIS)
 {
-	fd_set wfds;
+    fd_set wfds;
+    int selectret;
+
+    FD_ZERO(&wfds);
+    FD_SET(audio_fd, &wfds);
 
-	FD_SET( audio_fd, &wfds );
-	switch( select( audio_fd + 1, NULL, &wfds, NULL, NULL ) )
-	{
-		case -1:
-		case 0:
-			/* Error */
-			SDL_SetError("select() in NTO_WaitAudio failed: %s\n", strerror(errno));
-			break;
-		default:
-			if(FD_ISSET(audio_fd, &wfds))
-				return;
-	}
+    do {
+        selectret=select(audio_fd + 1, NULL, &wfds, NULL, NULL);
+        switch (selectret)
+        {
+            case -1:
+            case  0: SDL_SetError("NTO_WaitAudio(): select() failed: %s\n", strerror(errno));
+                     return;
+            default: if (FD_ISSET(audio_fd, &wfds))
+                     {
+                         return;
+                     }
+                     break;
+        }
+    } while(1);
 }
 
 static void NTO_PlayAudio(_THIS)
 {
-	int written, rval;
-	int towrite;
+    int written, rval;
+    int towrite;
+    void* pcmbuffer;
 
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr, "NTO_PlayAudio\n");
-	#endif
-
-	if( !this->enabled){
-		return;
-	}
+    if (!this->enabled)
+    {
+        return;
+    }
+    
+    towrite = this->spec.size;
+    pcmbuffer = pcm_buf;
 
-	towrite = pcm_len;
-	
-	/* Write the audio data, checking for EAGAIN (buffer full) and underrun */
-	do {
-		written = snd_pcm_plugin_write(audio_handle, pcm_buf, towrite);
-		#ifdef DEBUG_AUDIO
-		fprintf(stderr, "NTO_PlayAudio: written = %d towrite = %d\n",written,towrite);
-		#endif
-		if (written != towrite){
-			if ((errno == EAGAIN) || (errno == EWOULDBLOCK)){
-				SDL_Delay(1);   /* Let a little CPU time go by and try to write again */
-				#ifdef DEBUG_AUDIO
-				fprintf(stderr, "errno == EAGAIN written %d\n", written);
-				#endif
-				towrite -= written; //we wrote some data
-				continue;
-			}		
-			else if((errno == EINVAL) || (errno == EIO)){
-				if(errno == EIO){
-					#ifdef DEBUG_AUDIO
-					fprintf(stderr,"snd_pcm_plugin_write failed EIO: %s\n", snd_strerror(written));
-					#endif
-				}
-				if(errno == EINVAL){
-					#ifdef DEBUG_AUDIO
-					fprintf(stderr,"snd_pcm_plugin_write failed EINVAL: %s\n", snd_strerror(written));	
-					#endif
-				}
-				
-				memset(&cstatus, 0, sizeof(cstatus));
-				if( (rval = snd_pcm_plugin_status(audio_handle, &cstatus)) < 0 ){
-					#ifdef DEBUG_AUDIO
-					fprintf(stderr, "snd_pcm_plugin_status failed %s\n",snd_strerror(rval));
-					#endif
-					SDL_SetError("snd_pcm_plugin_status failed: %s\n", snd_strerror(rval));
-					return;
-				}	
-		        
-				if ( (cstatus.status == SND_PCM_STATUS_UNDERRUN) || (cstatus.status == SND_PCM_STATUS_READY) ){
-					#ifdef DEBUG_AUDIO
-					fprintf(stderr, "buffer underrun\n");
-					#endif
-					if ( (rval = snd_pcm_plugin_prepare (audio_handle,SND_PCM_CHANNEL_PLAYBACK)) < 0 ){
-						#ifdef DEBUG_AUDIO
-						fprintf(stderr, "NTO_PlayAudio: prepare failed %s\n",snd_strerror(rval));
-						#endif
-						SDL_SetError("snd_pcm_plugin_prepare failed: %s\n",snd_strerror(rval) );
-						return;
-					}
-				}		        		
- 				continue;
-			}
-			else{
-				#ifdef DEBUG_AUDIO
-				fprintf(stderr, "NTO_PlayAudio: snd_pcm_plugin_write failed unknown errno %d %s\n",errno, snd_strerror(rval));
-				#endif
-				return;
-			}
-			
-		}
-		else
-		{
-			towrite -= written; //we wrote all remaining data
-		}
-	} while ( (towrite > 0)  && (this->enabled) );
+    /* Write the audio data, checking for EAGAIN (buffer full) and underrun */
+    do {
+        written = snd_pcm_plugin_write(audio_handle, pcm_buf, towrite);
+        if (written != towrite)
+        {
+            if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
+            {
+                /* Let a little CPU time go by and try to write again */
+                SDL_Delay(1);
+                /* if we wrote some data */
+                towrite -= written;
+                pcmbuffer += written * this->spec.channels;
+                continue;
+            }		
+            else
+            {
+                if ((errno == EINVAL) || (errno == EIO))
+                {
+                    memset(&cstatus, 0, sizeof(cstatus));
+                    cstatus.channel = SND_PCM_CHANNEL_PLAYBACK;
+                    if ((rval = snd_pcm_plugin_status(audio_handle, &cstatus)) < 0)
+                    {
+                        SDL_SetError("NTO_PlayAudio(): snd_pcm_plugin_status failed: %s\n", snd_strerror(rval));
+                        return;
+                    }	
+                    if ((cstatus.status == SND_PCM_STATUS_UNDERRUN) || (cstatus.status == SND_PCM_STATUS_READY))
+                    {
+                        if ((rval = snd_pcm_plugin_prepare(audio_handle, SND_PCM_CHANNEL_PLAYBACK)) < 0)
+                        {
+                            SDL_SetError("NTO_PlayAudio(): snd_pcm_plugin_prepare failed: %s\n", snd_strerror(rval));
+                            return;
+                        }
+                    }		        		
+                    continue;
+                }
+                else
+                {
+                    return;
+                }
+            }
+        }
+        else
+        {
+            /* we wrote all remaining data */
+            towrite -= written;
+            pcmbuffer += written * this->spec.channels;
+        }
+    } while ((towrite > 0)  && (this->enabled));
 
-	/* If we couldn't write, assume fatal error for now */
-	if ( towrite != 0 ) {
-		this->enabled = 0;
-	}
-	return;
+    /* If we couldn't write, assume fatal error for now */
+    if (towrite != 0)
+    {
+        this->enabled = 0;
+    }
+
+    return;
 }
 
-static Uint8 *NTO_GetAudioBuf(_THIS)
+static Uint8* NTO_GetAudioBuf(_THIS)
 {
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr, "NTO_GetAudioBuf: pcm_buf %X\n",(Uint8 *)pcm_buf);
-	#endif
-	return(pcm_buf);
+    return pcm_buf;
 }
 
 static void NTO_CloseAudio(_THIS)
 {
-	int rval;
+    int rval;
 
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr, "NTO_CloseAudio\n");
-	#endif
-
-	this->enabled = 0;
+    this->enabled = 0;
 
-	if ( audio_handle != NULL ) {
-		if ((rval = snd_pcm_plugin_flush(audio_handle,SND_PCM_CHANNEL_PLAYBACK)) < 0){
-			SDL_SetError("snd_pcm_plugin_flush failed: %s\n",snd_strerror(rval));
-			return;
-		}
-		if ((rval = snd_pcm_close(audio_handle)) < 0){
-			SDL_SetError("snd_pcm_close failed: %s\n",snd_strerror(rval));
-			return;
-		}
-		audio_handle = NULL;
-	}
+    if (audio_handle != NULL)
+    {
+        if ((rval = snd_pcm_plugin_flush(audio_handle, SND_PCM_CHANNEL_PLAYBACK)) < 0)
+        {
+            SDL_SetError("NTO_CloseAudio(): snd_pcm_plugin_flush failed: %s\n", snd_strerror(rval));
+            return;
+        }
+        if ((rval = snd_pcm_close(audio_handle)) < 0)
+        {
+            SDL_SetError("NTO_CloseAudio(): snd_pcm_close failed: %s\n",snd_strerror(rval));
+            return;
+        }
+        audio_handle = NULL;
+    }
 }
 
-static int NTO_OpenAudio(_THIS, SDL_AudioSpec *spec)
+static int NTO_OpenAudio(_THIS, SDL_AudioSpec* spec)
 {
-	int rval;
-	int format;
-	Uint16 test_format;
-	int twidth;
-	int found;
+    int rval;
+    int format;
+    Uint16 test_format;
+    int found;
 
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr, "NTO_OpenAudio\n");
-	#endif
-	
-	audio_handle = NULL;
-	this->enabled = 0;
+    audio_handle = NULL;
+    this->enabled = 0;
+
+    if (pcm_buf != NULL)
+    {
+        SDL_FreeAudioMem(pcm_buf); 
+        pcm_buf = NULL;
+    }
 
-	if ( pcm_buf != NULL ) {
-		free((Uint8 *)pcm_buf); 
-		pcm_buf = NULL;
-	}
-	 
-	/* initialize channel transfer parameters to default */
-	init_pcm_cparams(&cparams);
+    /* initialize channel transfer parameters to default */
+    NTO_InitAudioParams(&cparams);
 
-	/* Open the audio device */
-	rval = snd_pcm_open_preferred(&audio_handle, NULL, NULL, OPEN_FLAGS);
-	if ( rval < 0 ) {
-		SDL_SetError("snd_pcm_open failed: %s\n", snd_strerror(rval));
-		return(-1);
-	}
+    /* Open the audio device */
+    rval = snd_pcm_open_preferred(&audio_handle, &cardno, &deviceno, OPEN_FLAGS);
+    if (rval < 0)
+    {
+        SDL_SetError("NTO_OpenAudio(): snd_pcm_open failed: %s\n", snd_strerror(rval));
+        return (-1);
+    }
 
-	/* enable count status parameter */
-	if ((rval = snd_pcm_plugin_set_disable(audio_handle, PLUGIN_DISABLE_MMAP))<0){
-		SDL_SetError("snd_pcm_plugin_set_disable failed: %s\n", snd_strerror(rval));
-		return(-1);
-	}
+    if (!NTO_CheckBuggyCards(this, QSA_MMAP_WORKAROUND))
+    {
+        /* enable count status parameter */
+        if ((rval = snd_pcm_plugin_set_disable(audio_handle, PLUGIN_DISABLE_MMAP)) < 0)
+        {
+            SDL_SetError("snd_pcm_plugin_set_disable failed: %s\n", snd_strerror(rval));
+            return (-1);
+        }
+    }
 
-	/* Try for a closest match on audio format */
-	format = 0;
- 	found = 0; /* can't use format as SND_PCM_SFMT_U8 = 0 in nto */
-	for ( test_format = SDL_FirstAudioFormat(spec->format);	!found ; ) 
-	{
-		#ifdef DEBUG_AUDIO
-		fprintf(stderr, "Trying format 0x%4.4x spec->samples %d\n", test_format,spec->samples);
-		#endif
-		
-		/* if match found set format to equivalent ALSA format */
-		switch ( test_format ) {
-			case AUDIO_U8:
-				format = SND_PCM_SFMT_U8;
-				found = 1;
-				break;
-			case AUDIO_S8:
-				format = SND_PCM_SFMT_S8;
-				found = 1;
-				break;
-			case AUDIO_S16LSB:
-				format = SND_PCM_SFMT_S16_LE;
-				found = 1;
-				break;
-			case AUDIO_S16MSB:
-				format = SND_PCM_SFMT_S16_BE;
-				found = 1;
-				break;
-			case AUDIO_U16LSB:
-				format = SND_PCM_SFMT_U16_LE;
-				found = 1;
-				break;
-			case AUDIO_U16MSB:
-				format = SND_PCM_SFMT_U16_BE;
-				found = 1;
-				break;
-			default:
-				break;
-		}
-		if ( ! found ) {
-			test_format = SDL_NextAudioFormat();
-		}
-	}
+    /* Try for a closest match on audio format */
+    format = 0;
+    /* can't use format as SND_PCM_SFMT_U8 = 0 in nto */
+    found = 0;
 
-	/* assumes test_format not 0 on success */
-	if ( test_format == 0 ) {
-		SDL_SetError("Couldn't find any hardware audio formats");
-		return(-1);
-	}
+    for (test_format=SDL_FirstAudioFormat(spec->format); !found ;)
+    {
+        /* if match found set format to equivalent ALSA format */
+        switch (test_format)
+        {
+            case AUDIO_U8:
+                           format = SND_PCM_SFMT_U8;
+                           found = 1;
+                           break;
+            case AUDIO_S8:
+                           format = SND_PCM_SFMT_S8;
+                           found = 1;
+                           break;
+            case AUDIO_S16LSB:
+                           format = SND_PCM_SFMT_S16_LE;
+                           found = 1;
+                           break;
+            case AUDIO_S16MSB:
+                           format = SND_PCM_SFMT_S16_BE;
+                           found = 1;
+                           break;
+            case AUDIO_U16LSB:
+                           format = SND_PCM_SFMT_U16_LE;
+                           found = 1;
+                           break;
+            case AUDIO_U16MSB:
+                           format = SND_PCM_SFMT_U16_BE;
+                           found = 1;
+                           break;
+            default:
+                           break;
+        }
 
-	spec->format = test_format;
-
-	/* Set the audio format */
-	cparams.format.format = format;
+        if (!found)
+        {
+            test_format = SDL_NextAudioFormat();
+        }
+    }
 
-	/* Set mono or stereo audio (currently only two channels supported) */
-	cparams.format.voices = spec->channels;
-	
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"intializing channels %d\n", cparams.format.voices);
-	#endif
-
-	/* Set rate */
-	cparams.format.rate = spec->freq ;
-
-	/* Setup the transfer parameters according to cparams */
-	rval = snd_pcm_plugin_params(audio_handle, &cparams);
-	if (rval < 0) {
-		SDL_SetError("snd_pcm_channel_params failed: %s\n", snd_strerror (rval));
-		return(-1);
-	}
+    /* assumes test_format not 0 on success */
+    if (test_format == 0)
+    {
+        SDL_SetError("NTO_OpenAudio(): Couldn't find any hardware audio formats");
+        return (-1);
+    }
 
-	/*  Make sure channel is setup right one last time */
-	memset( &csetup, 0, sizeof( csetup ) );
-	csetup.channel = SND_PCM_CHANNEL_PLAYBACK;
-	if ( snd_pcm_plugin_setup( audio_handle, &csetup ) < 0 )
-	{
-		SDL_SetError("Unable to setup playback channel\n" );
-		return(-1);
-	}
-	else
-	{
-		#ifdef DEBUG_AUDIO
-		fprintf(stderr,"requested format: %d\n",cparams.format.format);
-		fprintf(stderr,"requested frag size: %d\n",cparams.buf.block.frag_size);
-		fprintf(stderr,"requested max frags: %d\n\n",cparams.buf.block.frags_max);
+    spec->format = test_format;
 
-		fprintf(stderr,"real format: %d\n", csetup.format.format );
-		fprintf(stderr,"real frag size : %d\n", csetup.buf.block.frag_size );
-		fprintf(stderr,"real max frags : %d\n", csetup.buf.block.frags_max );
-		#endif
-	}
+    /* Set the audio format */
+    cparams.format.format = format;
 
-	/*
-		Allocate memory to the audio buffer and initialize with silence (Note that
-		buffer size must be a multiple of fragment size, so find closest multiple)
-	*/
+    /* Set mono or stereo audio (currently only two channels supported) */
+    cparams.format.voices = spec->channels;
 	
-	twidth = snd_pcm_format_width(format);
-	if (twidth < 0) {
-		printf("snd_pcm_format_width failed\n");
-		twidth = 0;
-	}
+    /* Set rate */
+    cparams.format.rate = spec->freq;
 
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"format is %d bits wide\n",twidth);
-	#endif
+    /* Setup the transfer parameters according to cparams */
+    rval = snd_pcm_plugin_params(audio_handle, &cparams);
+    if (rval < 0)
+    {
+        SDL_SetError("NTO_OpenAudio(): snd_pcm_channel_params failed: %s\n", snd_strerror(rval));
+        return (-1);
+    }
 
-	pcm_len = spec->size ;
-	
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"pcm_len set to %d\n", pcm_len);
-	#endif
+    /* Make sure channel is setup right one last time */
+    memset(&csetup, 0x00, sizeof(csetup));
+    csetup.channel = SND_PCM_CHANNEL_PLAYBACK;
+    if (snd_pcm_plugin_setup(audio_handle, &csetup) < 0)
+    {
+        SDL_SetError("NTO_OpenAudio(): Unable to setup playback channel\n");
+        return -1;
+    }
+
 
-	if (pcm_len == 0){
-		pcm_len = csetup.buf.block.frag_size;
-	}
+    /* Calculate the final parameters for this audio specification */
+    SDL_CalculateAudioSpec(spec);
+
+    pcm_len = spec->size;
+
+    if (pcm_len==0)
+    {
+        pcm_len = csetup.buf.block.frag_size * spec->channels * (snd_pcm_format_width(format)/8);
+    }
 
-	pcm_buf = (Uint8*)malloc(pcm_len);
-	if (pcm_buf == NULL) {
-		SDL_SetError("pcm_buf malloc failed\n");
-		return(-1);
-	}
-	memset(pcm_buf,spec->silence,pcm_len);
-
-	#ifdef DEBUG_AUDIO
-	fprintf(stderr,"pcm_buf malloced and silenced.\n");
-	#endif
-
-	/* get the file descriptor */
-	if( (audio_fd = snd_pcm_file_descriptor(audio_handle, SND_PCM_CHANNEL_PLAYBACK)) < 0){
-		fprintf(stderr, "snd_pcm_file_descriptor failed with error code: %d\n", audio_fd);
-	}
+    /* Allocate memory to the audio buffer and initialize with silence (Note that
+       buffer size must be a multiple of fragment size, so find closest multiple)
+    */
+    pcm_buf = (Uint8*)SDL_AllocAudioMem(pcm_len);
+    if (pcm_buf == NULL)
+    {
+        SDL_SetError("NTO_OpenAudio(): pcm buffer allocation failed\n");
+        return (-1);
+    }
+    memset(pcm_buf, spec->silence, pcm_len);
 
-	/* Trigger audio playback */
-	rval = snd_pcm_plugin_prepare( audio_handle, SND_PCM_CHANNEL_PLAYBACK);
-	if (rval < 0) {
-		SDL_SetError("snd_pcm_plugin_prepare failed: %s\n", snd_strerror (rval));
-		return(-1);
-	}
+    /* get the file descriptor */
+    if ((audio_fd = snd_pcm_file_descriptor(audio_handle, SND_PCM_CHANNEL_PLAYBACK)) < 0)
+    {
+        SDL_SetError("NTO_OpenAudio(): snd_pcm_file_descriptor failed with error code: %s\n", snd_strerror(rval));
+        return (-1);
+    }
 
-	this->enabled = 1;
+    /* Trigger audio playback */
+    rval = snd_pcm_plugin_prepare(audio_handle, SND_PCM_CHANNEL_PLAYBACK);
+    if (rval < 0)
+    {
+        SDL_SetError("snd_pcm_plugin_prepare failed: %s\n", snd_strerror(rval));
+        return (-1);
+    }
 
-	/* Get the parent process id (we're the parent of the audio thread) */
-	parent = getpid();
+    this->enabled = 1;
 
-	/* We're ready to rock and roll. :-) */
-	return(0);
+    /* Get the parent process id (we're the parent of the audio thread) */
+    parent = getpid();
+
+    /* We're really ready to rock and roll. :-) */
+    return (0);
 }