Resampling testing.

research/ma_resampler.h

+/* Resampling research. Public domain. */
+
+#ifndef ma_resampler_h
+#define ma_resampler_h
+
+typedef enum
+{
+    ma_resample_algorithm_linear = 0,   /* Default. Fastest. */
+    ma_resample_algorithm_sinc          /* Slower. */
+} ma_resample_algorithm;
+
+/*
+Simple high-level API for resampling 32-bit floating point samples.
+
+Use ma_calculate_frame_count_after_src() to determine the required output buffer size.
+*/
+ma_result ma_resample_f32(ma_resample_algorithm algorithm, ma_uint32 sampleRateOut, ma_uint32 sampleRateIn, ma_uint64 sampleCountOut, float* pSamplesOut, ma_uint64 sampleCountIn, float* pSamplesIn);
+
+#endif  /* ma_resampler_h */
+
+/*
+Implementation
+*/
+#ifdef MINIAUDIO_IMPLEMENTATION
+
+#ifndef MA_RESAMPLER_MIN_RATIO
+#define MA_RESAMPLER_MIN_RATIO 0.02083333
+#endif
+#ifndef MA_RESAMPLER_MAX_RATIO
+#define MA_RESAMPLER_MAX_RATIO 48.0
+#endif
+
+ma_result ma_resample_f32__linear(ma_uint32 sampleRateOut, ma_uint32 sampleRateIn, ma_uint64 sampleCountOut, float* pSamplesOut, ma_uint64 sampleCountIn, float* pSamplesIn)
+{
+    double ratio = (double)sampleRateIn / (double)sampleRateOut;
+    double timeIn  = 0;
+    double timeOut = 0;
+
+    /* Fast path if the sample rates are the same. */
+    if (sampleRateOut == sampleRateIn) {
+        MA_COPY_MEMORY(pSamplesOut, pSamplesIn, (size_t)ma_min(sampleCountOut, sampleCountIn) * sizeof(float));
+        return MA_SUCCESS;
+    }
+
+    /* Do nothing if there's no input. */
+    if (sampleCountOut == 0 || sampleCountIn == 0) {
+        return MA_SUCCESS;
+    }
+
+
+    /* The first output sample should always be the same as the input sample. */
+    pSamplesOut[0] = pSamplesIn[0];
+    timeIn  += ratio;
+    timeOut += 1;
+
+    for (;;) {
+        ma_uint64 iTimeIn;
+        ma_uint64 iTimeOut;
+
+        iTimeIn = (ma_uint64)timeIn;
+        if (iTimeIn >= sampleCountIn) {
+            break;
+        }
+
+        iTimeOut = (ma_uint64)timeOut;
+        if (iTimeOut >= sampleCountOut) {
+            break;
+        }
+
+        /* To linearly interpolate we need the previous and next input samples. */
+        {
+            ma_uint64 iTimeInPrev = iTimeIn;
+            ma_uint64 iTimeInNext = (ma_uint64)ceil(timeIn);
+
+            if (iTimeInNext >= sampleCountIn) {
+                iTimeInNext = iTimeInPrev;  /* <-- We could instead terminate here which would make the output a few samples shorter. */
+            }
+
+            pSamplesOut[iTimeOut] = ma_mix_f32_fast(pSamplesIn[iTimeInPrev], pSamplesIn[iTimeInNext], (float)(timeIn - iTimeIn));
+
+            /* Try some kind of low-pass filter. */
+        #if 1
+            {
+                double cutoff = ma_min(sampleRateIn, sampleRateOut) * 0.5;
+                double RC = 1.0/(cutoff*MA_TAU_D); 
+                double dt = 1.0/sampleRateOut;
+                float alpha = (float)(dt/(RC+dt));
+                pSamplesOut[iTimeOut] = pSamplesOut[iTimeOut-1] + (alpha*(pSamplesOut[iTimeOut] - pSamplesOut[iTimeOut-1]));
+            }
+        #endif
+        }
+
+        timeIn  += ratio;
+        timeOut += 1;
+    }
+
+    return MA_INVALID_ARGS;
+}
+
+
+double ma_sinc_hann(double n, int N)
+{
+    double s = sin(MA_PI_D*n/N);
+    return s*s;
+}
+
+ma_result ma_resample_f32__sinc(ma_uint32 sampleRateOut, ma_uint32 sampleRateIn, ma_uint64 sampleCountOut, float* pSamplesOut, ma_uint64 sampleCountIn, float* pSamplesIn)
+{
+    double ratio = (double)sampleRateIn / (double)sampleRateOut;
+    double timeIn  = 0;
+    double timeOut = 0;
+    double samplingPeriodIn = 1.0/sampleRateIn;
+    int windowWidth = 32;
+
+    /* Fast path if the sample rates are the same. */
+    if (sampleRateOut == sampleRateIn) {
+        MA_COPY_MEMORY(pSamplesOut, pSamplesIn, (size_t)ma_min(sampleCountOut, sampleCountIn) * sizeof(float));
+        return MA_SUCCESS;
+    }
+
+    /* Do nothing if there's no input. */
+    if (sampleCountOut == 0 || sampleCountIn == 0) {
+        return MA_SUCCESS;
+    }
+
+
+    /* The first output sample should always be the same as the input sample. */
+    pSamplesOut[0] = pSamplesIn[0];
+    timeIn  += ratio;
+    timeOut += 1;
+
+    for (;;) {
+        ma_uint64 iTimeIn;
+        ma_uint64 iTimeOut;
+
+        iTimeIn = (ma_uint64)timeIn;
+        if (iTimeIn >= sampleCountIn) {
+            break;
+        }
+
+        iTimeOut = (ma_uint64)timeOut;
+        if (iTimeOut >= sampleCountOut) {
+            break;
+        }
+
+        /* To linearly interpolate we need the previous and next input samples. */
+        {
+            ma_uint64 iTimeInPrev = iTimeIn;
+            ma_uint64 iTimeInNext = (ma_uint64)ceil(timeIn);
+
+            if (iTimeInNext >= sampleCountIn) {
+                iTimeInNext = iTimeInPrev;  /* <-- We could instead terminate here which would make the output a few samples shorter. */
+            }
+
+
+
+        #if 0
+            pSamplesOut[iTimeOut] = ma_mix_f32_fast(pSamplesIn[iTimeInPrev], pSamplesIn[iTimeInNext], (float)(timeIn - iTimeIn));
+        #else
+            pSamplesOut[iTimeOut] = 0;
+            for (int i = -windowWidth; i < windowWidth; i += 1) {
+                if ((i < 0 && -i < iTimeIn) || i > 0 && i < sampleCountIn) {
+#if 0
+                    double t = (iTimeIn+n);
+                    double s = ma_sinc(sampleRateIn*t);
+                    pSamplesOut[iTimeOut] += pSamplesIn[(ma_uint64)(iTimeIn+n)] * s;
+#endif
+                }
+            }
+        #endif
+        }
+
+        timeIn  += ratio;
+        timeOut += 1;
+    }
+
+    return MA_INVALID_ARGS;
+}
+
+ma_result ma_resample_f32(ma_resample_algorithm algorithm, ma_uint32 sampleRateOut, ma_uint32 sampleRateIn, ma_uint64 sampleCountOut, float* pSamplesOut, ma_uint64 sampleCountIn, float* pSamplesIn)
+{
+    if (pSamplesOut == NULL || pSamplesIn == NULL) {
+        return MA_INVALID_ARGS;
+    }
+
+    switch (algorithm)
+    {
+        case ma_resample_algorithm_linear: return ma_resample_f32__linear(sampleRateOut, sampleRateIn, sampleCountOut, pSamplesOut, sampleCountIn, pSamplesIn);
+        case ma_resample_algorithm_sinc:   return ma_resample_f32__sinc  (sampleRateOut, sampleRateIn, sampleCountOut, pSamplesOut, sampleCountIn, pSamplesIn);
+        default: return MA_INVALID_ARGS;
+    }
+}
+
+#endif  /* MINIAUDIO_IMPLEMENTATION */
+
+
+#if 0
 /*
 Consider this code public domain.
 
@@ -1204,3 +1401,4 @@ ma_uint64 ma_resampler_seek__sinc(ma_resampler* pResampler, ma_uint64 frameCount
 }
 
 #endif
+#endif  /* 0 (Old Implementation)*/
\ No newline at end of file

research/tests/ma_resampler_test_0.c

+#define DR_FLAC_IMPLEMENTATION
+#include "../../extras/dr_flac.h"  /* Enables FLAC decoding. */
+#define DR_MP3_IMPLEMENTATION
+#include "../../extras/dr_mp3.h"   /* Enables MP3 decoding. */
 #define DR_WAV_IMPLEMENTATION
-#include "../../../../dr_libs/dr_wav.h"
+#include "../../extras/dr_wav.h"   /* Enables WAV decoding. */
+
 
 #define MA_DEBUG_OUTPUT
 #define MINIAUDIO_IMPLEMENTATION
 #include "../../miniaudio.h"
 #include "../ma_resampler.h"
 
+#define USE_NEW_RESAMPLER   1
+
+ma_uint64 g_outputFrameCount;
+void* g_pRunningFrameData;
+
+void data_callback(ma_device* pDevice, void* pOutput, const void* pInput, ma_uint32 frameCount)
+{
+    ma_uint32 framesToCopy;
+
+    framesToCopy = frameCount;
+    if (framesToCopy > (ma_uint32)g_outputFrameCount) {
+        framesToCopy = (ma_uint32)g_outputFrameCount;
+    }
+
+    MA_COPY_MEMORY(pOutput, g_pRunningFrameData, framesToCopy * ma_get_bytes_per_frame(pDevice->playback.format, pDevice->playback.channels));
+
+    g_pRunningFrameData = ma_offset_ptr(g_pRunningFrameData, framesToCopy * ma_get_bytes_per_frame(pDevice->playback.format, pDevice->playback.channels));
+    g_outputFrameCount -= framesToCopy;
+
+    (void)pInput;
+}
+
+int main(int argc, char** argv)
+{
+    ma_result result;
+    ma_decoder_config decoderConfig;
+    ma_uint64 inputFrameCount;
+    void* pInputFrameData;
+    ma_uint64 outputFrameCount = 0;
+    void* pOutputFrameData = NULL;
+    ma_device_config deviceConfig;
+    ma_device device;
+    ma_backend backend;
+
+    /* This example just resamples the input file to an exclusive device's native sample rate. */
+    if (argc < 2) {
+        printf("No input file.\n");
+        return -1;
+    }
+
+    decoderConfig = ma_decoder_config_init(ma_format_f32, 1, 0);
+
+    result = ma_decode_file(argv[1], &decoderConfig, &inputFrameCount, &pInputFrameData);
+    if (result != MA_SUCCESS) {
+        return (int)result;
+    }
+
+    backend = ma_backend_wasapi;
+
+    deviceConfig = ma_device_config_init(ma_device_type_playback);
+#if USE_NEW_RESAMPLER
+    deviceConfig.playback.shareMode = ma_share_mode_exclusive;  /* <-- We need to use exclusive mode to ensure there's no resampling going on by the OS. */
+    deviceConfig.sampleRate         = 0; /* <-- Always use the device's native sample rate. */
+#else
+    deviceConfig.playback.shareMode = ma_share_mode_shared;  /* <-- We need to use exclusive mode to ensure there's no resampling going on by the OS. */
+    deviceConfig.sampleRate         = decoderConfig.sampleRate;
+#endif
+    deviceConfig.playback.format    = decoderConfig.format;
+    deviceConfig.playback.channels  = decoderConfig.channels;
+    deviceConfig.dataCallback       = data_callback;
+    deviceConfig.pUserData          = NULL;
+
+    if (ma_device_init(NULL, &deviceConfig, &device) != MA_SUCCESS) {
+        printf("Failed to open playback device.\n");
+        ma_free(pInputFrameData);
+        return -3;
+    }
+
+#if USE_NEW_RESAMPLER
+    /* Resample. */
+    outputFrameCount = ma_calculate_frame_count_after_src(device.sampleRate, decoderConfig.sampleRate, inputFrameCount);
+    pOutputFrameData = ma_malloc((size_t)(outputFrameCount * ma_get_bytes_per_frame(device.playback.format, device.playback.channels)));
+    if (pOutputFrameData == NULL) {
+        printf("Out of memory.\n");
+        ma_free(pInputFrameData);
+        ma_device_uninit(&device);
+    }
+
+    ma_resample_f32(ma_resample_algorithm_sinc, device.playback.internalSampleRate, decoderConfig.sampleRate, outputFrameCount, pOutputFrameData, inputFrameCount, pInputFrameData);
+
+    g_pRunningFrameData = pOutputFrameData;
+    g_outputFrameCount = outputFrameCount;
+#else
+    g_pRunningFrameData = pInputFrameData;
+    g_outputFrameCount = inputFrameCount;
+#endif
+
+    if (ma_device_start(&device) != MA_SUCCESS) {
+        printf("Failed to start playback device.\n");
+        ma_device_uninit(&device);
+        ma_free(pInputFrameData);
+        ma_free(pOutputFrameData);
+        return -4;
+    }
+
+    printf("Press Enter to quit...");
+    getchar();
+
+    ma_device_uninit(&device);
+    ma_free(pInputFrameData);
+    ma_free(pOutputFrameData);
+
+    return 0;
+}
+
+#if 0
 #define SAMPLE_RATE_IN  44100
 #define SAMPLE_RATE_OUT 44100
 #define CHANNELS        1
@@ -71,4 +182,5 @@ int main(int argc, char** argv)
     (void)argc;
     (void)argv;
     return 0;
-}
+}
\ No newline at end of file
+#endif

tests/ma_test_0.vcxproj

@@ -319,14 +319,6 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
     </ClCompile>
     <ClCompile Include="..\examples\simple_playback.c">
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">false</ExcludedFromBuild>
-      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">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>
-    </ClCompile>
-    <ClCompile Include="..\examples\simple_playback_emscripten.c">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">true</ExcludedFromBuild>
@@ -334,7 +326,7 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
     </ClCompile>
-    <ClCompile Include="..\research\tests\ma_resampler_test_0.c">
+    <ClCompile Include="..\examples\simple_playback_emscripten.c">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">true</ExcludedFromBuild>
@@ -342,6 +334,14 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
     </ClCompile>
+    <ClCompile Include="..\research\tests\ma_resampler_test_0.c">
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">false</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">false</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">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>
+    </ClCompile>
     <ClCompile Include="ma_dithering.c">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>