Merge pull request #849 from chirs241097/wasapi

A few fixes for the WASAPI driver

src/drivers/fluid_wasapi.c

@@ -89,8 +89,15 @@ static const IID   _IID_IAudioRenderClient =
  *    audio.periods still determines the buffer size, but has no direct impact on
  *    the latency (at least according to Microsoft). The valid range for
  *    audio.period-size may vary depending on the driver and sample rate.
+ *  - In shared mode, audio.period-size is completely ignored. Instead, a value
+ *    provided by the audio driver is used. In theory this means the latency in
+ *    shared mode is out of fluidsynth's control, but you may still increase
+ *    audio.periods for a larger buffer to fix buffer underruns in case there
+ *    are any.
  *  - The sample rate and sample format of fluidsynth must be supported by the
- *    audio device in exclusive mode. Otherwise driver creation will fail.
+ *    audio device in exclusive mode. Otherwise driver creation will fail. Use
+ *    `fluidsynth ---query-audio-devices` to find out the modes supported by
+ *    the soundcards installed on the system.
  *  - In shared mode, if the sample rate of the synth doesn't match what is
  *    configured in the 'advanced' tab of the audio device properties dialog,
  *    Windows will automatically resample the output (obviously). Windows
@@ -331,7 +338,7 @@ void fluid_wasapi_audio_driver_settings(fluid_settings_t *settings)
 static DWORD WINAPI fluid_wasapi_audio_run(void *p)
 {
     fluid_wasapi_audio_driver_t *dev = (fluid_wasapi_audio_driver_t *)p;
-    DWORD time_to_sleep = dev->buffer_duration * 1000 / 2;
+    DWORD time_to_sleep;
     UINT32 pos;
     DWORD len;
     void *channels_out[2];
@@ -349,11 +356,6 @@ static DWORD WINAPI fluid_wasapi_audio_run(void *p)
     int needs_com_uninit = FALSE;
     int i;
 
-    if(time_to_sleep < 1)
-    {
-        time_to_sleep = 1;
-    }
-
     /* Clear format structure */
     ZeroMemory(&wfx, sizeof(WAVEFORMATEXTENSIBLE));
 
@@ -417,9 +419,19 @@ static DWORD WINAPI fluid_wasapi_audio_run(void *p)
     }
     else
     {
+        fluid_long_long_t defp;
         share_mode = AUDCLNT_SHAREMODE_SHARED;
         FLUID_LOG(FLUID_DBG, "wasapi: using shared mode.");
         dev->periods_reftime = 0;
+
+        //use default period size of the device
+        if(SUCCEEDED(IAudioClient_GetDevicePeriod(dev->aucl, &defp, NULL)))
+        {
+            dev->period_size = (int)(defp / 1e7 * dev->sample_rate);
+            dev->buffer_duration = dev->periods * dev->period_size / dev->sample_rate;
+            dev->buffer_duration_reftime = (fluid_long_long_t)(dev->buffer_duration * 1e7 + .5);
+            FLUID_LOG(FLUID_DBG, "wasapi: using device period size: %d", dev->period_size);
+        }
     }
 
     ret = IAudioClient_IsFormatSupported(dev->aucl, share_mode, (const WAVEFORMATEX *)&wfx, (WAVEFORMATEX **)&rwfx);
@@ -486,6 +498,11 @@ static DWORD WINAPI fluid_wasapi_audio_run(void *p)
 
     FLUID_LOG(FLUID_DBG, "wasapi: requested %d frames of buffers, got %u.", dev->periods * dev->period_size, dev->nframes);
     dev->buffer_duration = dev->nframes / dev->sample_rate;
+    time_to_sleep = dev->buffer_duration * 1000 / 2;
+    if(time_to_sleep < 1)
+    {
+        time_to_sleep = 1;
+    }
 
     dev->drybuf = FLUID_ARRAY(float *, dev->audio_channels * 2);
 
@@ -618,6 +635,8 @@ static int fluid_wasapi_write_processed_channels(void *data, int len,
     fluid_wasapi_audio_driver_t *drv = (fluid_wasapi_audio_driver_t *) data;
     float *optr[FLUID_WASAPI_MAX_OUTPUTS * 2];
     int16_t *ioptr[FLUID_WASAPI_MAX_OUTPUTS * 2];
+    int efx_nch = 0;
+    float **efx_buf = NULL;
 
     for(ch = 0; ch < drv->channels_count; ++ch)
     {
@@ -626,7 +645,12 @@ static int fluid_wasapi_write_processed_channels(void *data, int len,
         ioptr[ch] = (int16_t *)channels_out[ch] + channels_off[ch];
     }
 
-    ret = drv->func(drv->user_pointer, len, 0, NULL, drv->channels_count, drv->drybuf);
+    if(drv->func == (fluid_audio_func_t)fluid_synth_process)
+    {
+        efx_nch = drv->channels_count;
+        efx_buf = drv->drybuf;
+    }
+    ret = drv->func(drv->user_pointer, len, efx_nch, efx_buf, drv->channels_count, drv->drybuf);
 
     for(ch = 0; ch < drv->channels_count; ++ch)
     {
@@ -779,7 +803,7 @@ static void fluid_wasapi_finddev_callback(IMMDevice *dev, void *data)
 {
     fluid_wasapi_finddev_data_t *d = (fluid_wasapi_finddev_data_t *)data;
     int nsz;
-    char *name;
+    char *name = NULL;
     wchar_t *id = NULL;
     IPropertyStore *prop = NULL;
     PROPVARIANT var;