Add initial support for dithering.

tests/mal_dithering.c

@@ -0,0 +1,138 @@
+#define MAL_USE_REFERENCE_CONVERSION_APIS
+#define MAL_IMPLEMENTATION
+#include "../mini_al.h"
+
+// Two converters are needed here. One for converting f32 samples from the sine wave generator to the input format,
+// and another for converting the input format to the output format for device output.
+mal_sine_wave sineWave;
+mal_format_converter converterIn;
+mal_format_converter converterOut;
+
+mal_uint32 on_convert_samples_in(mal_format_converter* pConverter, mal_uint32 frameCount, void* pFrames, void* pUserData)
+{
+    (void)pUserData;
+    mal_assert(pConverter->config.formatIn == mal_format_f32);
+
+    mal_sine_wave* pSineWave = (mal_sine_wave*)pConverter->config.pUserData;
+    mal_assert(pSineWave);
+
+    return (mal_uint32)mal_sine_wave_read(pSineWave, frameCount, pFrames);
+}
+
+mal_uint32 on_convert_samples_out(mal_format_converter* pConverter, mal_uint32 frameCount, void* pFrames, void* pUserData)
+{
+    (void)pUserData;
+
+    mal_format_converter* pConverterIn = (mal_format_converter*)pConverter->config.pUserData;
+    mal_assert(pConverterIn != NULL);
+
+    return (mal_uint32)mal_format_converter_read(pConverterIn, frameCount, pFrames, NULL);
+}
+
+mal_uint32 on_send_to_device__original(mal_device* pDevice, mal_uint32 frameCount, void* pFrames)
+{
+    (void)pDevice;
+    mal_assert(pDevice->format == mal_format_f32);
+    mal_assert(pDevice->channels == 1);
+
+    return (mal_uint32)mal_sine_wave_read(&sineWave, frameCount, pFrames);
+}
+
+mal_uint32 on_send_to_device__dithered(mal_device* pDevice, mal_uint32 frameCount, void* pFrames)
+{
+    mal_assert(pDevice->channels == 1);
+
+    mal_format_converter* pConverter = (mal_format_converter*)pDevice->pUserData;
+    mal_assert(pConverter != NULL);
+    mal_assert(pDevice->format == pConverter->config.formatOut);
+
+    return (mal_uint32)mal_format_converter_read(pConverter, frameCount, pFrames, NULL);
+}
+
+int do_dithering_test()
+{
+    mal_sine_wave_init(0.5, 400, 48000, &sineWave);
+
+
+    mal_device_config config = mal_device_config_init_playback(mal_format_f32, 1, 0, on_send_to_device__original);
+    mal_device device;
+    mal_result result;
+
+    // We first play the sound the way it's meant to be played.
+    result = mal_device_init(NULL, mal_device_type_playback, NULL, &config, NULL, &device);
+    if (result != MAL_SUCCESS) {
+        return -1;
+    }
+
+    result = mal_device_start(&device);
+    if (result != MAL_SUCCESS) {
+        return -2;
+    }
+
+    printf("Press Enter to play enable dithering.\n");
+    getchar();
+    mal_device_uninit(&device);
+
+
+    // Now we play the sound after it's run through a dithered format converter.
+    mal_sine_wave_init(0.5, 400, 48000, &sineWave);
+
+    mal_format srcFormat = mal_format_s24;
+    mal_format dstFormat = mal_format_s16;
+    mal_dither_mode ditherMode = mal_dither_mode_triangle;
+
+    mal_format_converter_config converterInConfig;
+    mal_zero_object(&converterInConfig);
+    converterInConfig.formatIn = mal_format_f32;  // <-- From the sine wave generator.
+    converterInConfig.formatOut = srcFormat;
+    converterInConfig.channels = config.channels;
+    converterInConfig.ditherMode = mal_dither_mode_none;
+    converterInConfig.onRead = on_convert_samples_in;
+    converterInConfig.pUserData = &sineWave;
+    result = mal_format_converter_init(&converterInConfig, &converterIn);
+    if (result != MAL_SUCCESS) {
+        return -3;
+    }
+
+    mal_format_converter_config converterOutConfig;
+    mal_zero_object(&converterInConfig);
+    converterOutConfig.formatIn = srcFormat;
+    converterOutConfig.formatOut = dstFormat;
+    converterOutConfig.channels = config.channels;
+    converterOutConfig.ditherMode = ditherMode;
+    converterOutConfig.onRead = on_convert_samples_out;
+    converterOutConfig.pUserData = &converterIn;
+    result = mal_format_converter_init(&converterOutConfig, &converterOut);
+    if (result != MAL_SUCCESS) {
+        return -3;
+    }
+
+    config = mal_device_config_init_playback(converterOutConfig.formatOut, 1, 0, on_send_to_device__dithered);
+
+    result = mal_device_init(NULL, mal_device_type_playback, NULL, &config, &converterOut, &device);
+    if (result != MAL_SUCCESS) {
+        return -1;
+    }
+
+    result = mal_device_start(&device);
+    if (result != MAL_SUCCESS) {
+        return -2;
+    }
+
+    printf("Press Enter to stop.\n");
+    getchar();
+
+    return 0;
+}
+
+int main(int argc, char** argv)
+{
+    (void)argc;
+    (void)argv;
+
+
+    do_dithering_test();
+
+
+    return 0;
+}

tests/mal_test_0.vcxproj

@@ -260,6 +260,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="mal_dithering.c" />
     <ClCompile Include="mal_profiling.c">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>
@@ -269,12 +270,12 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
     </ClCompile>
     <ClCompile Include="mal_test_0.c">
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
     </ClCompile>
     <ClCompile Include="mal_test_0.cpp">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>

tests/mal_test_0.vcxproj.filters

@@ -24,6 +24,9 @@
     <ClCompile Include="mal_profiling.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="mal_dithering.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\mini_al.h">