Another potential fix for some full-duplex glitching.

This change makes it so reading and writing is done on the smaller of
the period sizes between capture and playback devices.

mini_al.h

@@ -9216,8 +9216,9 @@ mal_result mal_device_map_next_playback_buffer__dsound(mal_device* pDevice)
 {
     DWORD periodSizeInBytes = (pDevice->playback.internalBufferSizeInFrames / pDevice->playback.internalPeriods) * mal_get_bytes_per_frame(pDevice->playback.internalFormat, pDevice->playback.internalChannels);
     DWORD lockOffset = (pDevice->dsound.iNextPeriodPlayback * periodSizeInBytes);
+    DWORD lockSizeInBytes = periodSizeInBytes;
     DWORD mappedSizeInBytes;
-    HRESULT hr = mal_IDirectSoundBuffer_Lock((mal_IDirectSoundBuffer*)pDevice->dsound.pPlaybackBuffer, lockOffset, periodSizeInBytes, &pDevice->dsound.pMappedBufferPlayback, &mappedSizeInBytes, NULL, NULL, 0);
+    HRESULT hr = mal_IDirectSoundBuffer_Lock((mal_IDirectSoundBuffer*)pDevice->dsound.pPlaybackBuffer, lockOffset, lockSizeInBytes, &pDevice->dsound.pMappedBufferPlayback, &mappedSizeInBytes, NULL, NULL, 0);
     if (FAILED(hr)) {
         return mal_post_error(pDevice, MAL_LOG_LEVEL_ERROR, "[DirectSound] Failed to map buffer from playback device in preparation for writing to the device.", MAL_FAILED_TO_MAP_DEVICE_BUFFER);
     }
@@ -9225,6 +9226,8 @@ mal_result mal_device_map_next_playback_buffer__dsound(mal_device* pDevice)
     pDevice->dsound.mappedBufferFramesCapacityPlayback  = (mal_uint32)mappedSizeInBytes / mal_get_bytes_per_frame(pDevice->playback.internalFormat, pDevice->playback.internalChannels);
     pDevice->dsound.mappedBufferFramesRemainingPlayback = (mal_uint32)mappedSizeInBytes / mal_get_bytes_per_frame(pDevice->playback.internalFormat, pDevice->playback.internalChannels);
 
+    //printf("TRACE 1: Playback: iNextPeriod=%d, internalBufferSizeInFrames=%d, periodSizeInBytes=%d, mappedSizeInBytes=%d\n", pDevice->dsound.iNextPeriodPlayback, pDevice->playback.internalBufferSizeInFrames, periodSizeInBytes, mappedSizeInBytes);
+
     return MAL_SUCCESS;
 }
 
@@ -9346,8 +9349,9 @@ mal_result mal_device_map_next_capture_buffer__dsound(mal_device* pDevice)
 {
     DWORD periodSizeInBytes = (pDevice->capture.internalBufferSizeInFrames / pDevice->capture.internalPeriods) * mal_get_bytes_per_frame(pDevice->capture.internalFormat, pDevice->capture.internalChannels);
     DWORD lockOffset = (pDevice->dsound.iNextPeriodCapture * periodSizeInBytes);
+    DWORD lockSizeInBytes = periodSizeInBytes;
     DWORD mappedSizeInBytes;
-    HRESULT hr = mal_IDirectSoundCaptureBuffer_Lock((mal_IDirectSoundCaptureBuffer*)pDevice->dsound.pCaptureBuffer, lockOffset, periodSizeInBytes, &pDevice->dsound.pMappedBufferCapture, &mappedSizeInBytes, NULL, NULL, 0);
+    HRESULT hr = mal_IDirectSoundCaptureBuffer_Lock((mal_IDirectSoundCaptureBuffer*)pDevice->dsound.pCaptureBuffer, lockOffset, lockSizeInBytes, &pDevice->dsound.pMappedBufferCapture, &mappedSizeInBytes, NULL, NULL, 0);
     if (FAILED(hr)) {
         return mal_post_error(pDevice, MAL_LOG_LEVEL_ERROR, "[DirectSound] Failed to map buffer from capture device in preparation for writing to the device.", MAL_FAILED_TO_MAP_DEVICE_BUFFER);
     }
@@ -9355,6 +9359,8 @@ mal_result mal_device_map_next_capture_buffer__dsound(mal_device* pDevice)
     pDevice->dsound.mappedBufferFramesCapacityCapture  = (mal_uint32)mappedSizeInBytes / mal_get_bytes_per_frame(pDevice->capture.internalFormat, pDevice->capture.internalChannels);
     pDevice->dsound.mappedBufferFramesRemainingCapture = (mal_uint32)mappedSizeInBytes / mal_get_bytes_per_frame(pDevice->capture.internalFormat, pDevice->capture.internalChannels);
 
+    //printf("TRACE 1: Capture: internalBufferSizeInFrames=%d, periodSizeInBytes=%d, mappedSizeInBytes=%d\n", pDevice->capture.internalBufferSizeInFrames, periodSizeInBytes, mappedSizeInBytes);
+
     return MAL_SUCCESS;
 }
 
@@ -21805,12 +21811,19 @@ mal_thread_result MAL_THREADCALL mal_worker_thread(void* pData)
         );
 
         mal_uint32 periodSizeInFrames;
-        if (pDevice->type == mal_device_type_capture || pDevice->type == mal_device_type_duplex) {
+        if (pDevice->type == mal_device_type_capture) {
             mal_assert(pDevice->capture.internalBufferSizeInFrames >= pDevice->capture.internalPeriods);
             periodSizeInFrames = pDevice->capture.internalBufferSizeInFrames / pDevice->capture.internalPeriods;
-        } else {
+        } else if (pDevice->type == mal_device_type_playback) {
             mal_assert(pDevice->playback.internalBufferSizeInFrames >= pDevice->playback.internalPeriods);
             periodSizeInFrames = pDevice->playback.internalBufferSizeInFrames / pDevice->playback.internalPeriods;
+        } else {
+            mal_assert(pDevice->capture.internalBufferSizeInFrames >= pDevice->capture.internalPeriods);
+            mal_assert(pDevice->playback.internalBufferSizeInFrames >= pDevice->playback.internalPeriods);
+            periodSizeInFrames = mal_min(
+                pDevice->capture.internalBufferSizeInFrames / pDevice->capture.internalPeriods,
+                pDevice->playback.internalBufferSizeInFrames / pDevice->playback.internalPeriods
+            );
         }
         
 

tests/mal_duplex.c

@@ -31,7 +31,7 @@ void data_callback(mal_device* pDevice, void* pOutput, const void* pInput, mal_u
     /* In this test the format and channel count are the same for both input and output which means we can just memcpy(). */
     mal_copy_memory(pOutput, pInput, frameCount * mal_get_bytes_per_frame(pDevice->capture.format, pDevice->capture.channels));
 
-#if 0
+#if 1
     /* Also write to a wav file for debugging. */
     drwav* pWav = (drwav*)pDevice->pUserData;
     mal_assert(pWav != NULL);
@@ -44,7 +44,7 @@ int main(int argc, char** argv)
 {
     mal_result result;
 
-#if 0
+#if 1
     drwav_data_format wavFormat;
     wavFormat.container     = drwav_container_riff;
     wavFormat.format        = DR_WAVE_FORMAT_PCM;
@@ -60,7 +60,7 @@ int main(int argc, char** argv)
 #endif
     
 
-    mal_backend backend = mal_backend_wasapi;
+    mal_backend backend = mal_backend_dsound;
 
     mal_context_config contextConfig = mal_context_config_init();
     contextConfig.logCallback = log_callback;
@@ -81,11 +81,12 @@ int main(int argc, char** argv)
     deviceConfig.playback.channels  = 2;
     deviceConfig.playback.shareMode = mal_share_mode_shared;
     deviceConfig.sampleRate         = 44100;
-    deviceConfig.bufferSizeInMilliseconds = 100;
-    deviceConfig.periods            = 2;
+    //deviceConfig.bufferSizeInMilliseconds = 60;
+    deviceConfig.bufferSizeInFrames = 4096;
+    //deviceConfig.periods            = 3;
     deviceConfig.dataCallback       = data_callback;
     deviceConfig.stopCallback       = stop_callback;
-    deviceConfig.pUserData          = NULL/*&wav*/;
+    deviceConfig.pUserData          = &wav;
 
     mal_device device;
     result = mal_device_init(&context, &deviceConfig, &device);
@@ -107,7 +108,7 @@ int main(int argc, char** argv)
 #endif
 
     mal_device_uninit(&device);
-    /*drwav_uninit(&wav);*/
+    drwav_uninit(&wav);
 
     (void)argc;
     (void)argv;