Add vocoder node and duplex example.

research/_examples/duplex_effect.c

+/*
+Demonstrates how to apply an effect to a duplex stream using the node graph system.
+
+This example applies a vocoder effect to the input stream before outputting it. A custom node
+called `ma_vocoder_node` is used to achieve the effect which can be found in the extras folder in
+the miniaudio repository. The vocoder node uses https://github.com/blastbay/voclib to achieve the
+effect.
+*/
+#define MINIAUDIO_IMPLEMENTATION
+#include "../../miniaudio.h"
+#include "../miniaudio_engine.h"
+#include "../_extras/nodes/ma_vocoder_node/ma_vocoder_node.c"
+
+#include <stdio.h>
+
+#define DEVICE_FORMAT      ma_format_f32;   /* Must always be f32 for this example because the node graph system only works with this. */
+#define DEVICE_CHANNELS    2                /* The vocoder only supports 1 or 2 channels. */
+
+static ma_audio_buffer_ref g_sourceData;    /* The underlying data source of the source node. */
+static ma_waveform         g_exciteData;    /* The underlying data source of the excite node. */
+static ma_data_source_node g_sourceNode;    /* A data source node containing the source data we'll be sending through to the vocoder. This will be routed into the first bus of the vocoder node. */
+static ma_data_source_node g_exciteNode;    /* A data source node containing the excite data we'll be sending through to the vocoder. This will be routed into the second bus of the vocoder node. */
+static ma_vocoder_node     g_vocoderNode;   /* The vocoder node. */
+static ma_node_graph       g_nodeGraph;
+
+void data_callback(ma_device* pDevice, void* pOutput, const void* pInput, ma_uint32 frameCount)
+{
+    MA_ASSERT(pDevice->capture.format == pDevice->playback.format);
+    MA_ASSERT(pDevice->capture.channels == pDevice->playback.channels);
+
+    /* Make sure the audio buffer has it's data buffer updated. */
+    ma_audio_buffer_ref_set_data(&g_sourceData, pInput, frameCount);
+
+    /* With the source buffer configured we can now read directly from the node graph. */
+    ma_node_graph_read_pcm_frames(&g_nodeGraph, pOutput, frameCount, NULL);
+}
+
+int main(int argc, char** argv)
+{
+    ma_result result;
+    ma_device_config deviceConfig;
+    ma_device device;
+    ma_node_graph_config nodeGraphConfig;
+    ma_vocoder_node_config vocoderNodeConfig;
+    ma_data_source_node_config sourceNodeConfig;
+    ma_data_source_node_config exciteNodeConfig;
+    ma_waveform_config waveformConfig;
+
+    deviceConfig = ma_device_config_init(ma_device_type_duplex);
+    deviceConfig.capture.pDeviceID  = NULL;
+    deviceConfig.capture.format     = DEVICE_FORMAT;
+    deviceConfig.capture.channels   = DEVICE_CHANNELS;
+    deviceConfig.capture.shareMode  = ma_share_mode_shared;
+    deviceConfig.playback.pDeviceID = NULL;
+    deviceConfig.playback.format    = DEVICE_FORMAT;
+    deviceConfig.playback.channels  = DEVICE_CHANNELS;
+    deviceConfig.dataCallback       = data_callback;
+    result = ma_device_init(NULL, &deviceConfig, &device);
+    if (result != MA_SUCCESS) {
+        return result;
+    }
+
+
+    /* Now we can setup our node graph. */
+    nodeGraphConfig = ma_node_graph_config_init(device.capture.channels);
+
+    result = ma_node_graph_init(&nodeGraphConfig, NULL, &g_nodeGraph);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize node graph.");
+        goto done0;
+    }
+
+
+    /* Vocoder. Attached straight to the endpoint. */
+    vocoderNodeConfig = ma_vocoder_node_config_init(device.capture.channels, device.sampleRate);
+
+    result = ma_vocoder_node_init(&g_nodeGraph, &vocoderNodeConfig, NULL, &g_vocoderNode);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize vocoder node.");
+        goto done1;
+    }
+
+    ma_node_attach_output_bus(&g_vocoderNode, 0, ma_node_graph_get_endpoint(&g_nodeGraph), 0);
+
+    /* Amplify the volume of the vocoder output because in my testing it is a bit quiet. */
+    ma_node_set_output_bus_volume(&g_vocoderNode, 0, 2);
+
+
+    /* Source/carrier. Attached to input bus 0 of the vocoder node. */
+    result = ma_audio_buffer_ref_init(device.capture.format, device.capture.channels, &g_sourceData);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize audio buffer for source.");
+        goto done2;
+    }
+
+    sourceNodeConfig = ma_data_source_node_config_init(&g_sourceData, MA_FALSE);
+
+    result = ma_data_source_node_init(&g_nodeGraph, &sourceNodeConfig, NULL, &g_sourceNode);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize source node.");
+        goto done2;
+    }
+
+    ma_node_attach_output_bus(&g_sourceNode, 0, &g_vocoderNode, 0);
+
+
+    /* Excite/modulator. Attached to input bus 1 of the vocoder node. */
+    waveformConfig = ma_waveform_config_init(device.capture.format, 1, device.sampleRate, ma_waveform_type_sawtooth, 1.0, 500); /* Must be one channel. */
+
+    result = ma_waveform_init(&waveformConfig, &g_exciteData);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize waveform for excite node.");
+        goto done3;
+    }
+
+    exciteNodeConfig = ma_data_source_node_config_init(&g_exciteData, MA_FALSE);
+
+    result = ma_data_source_node_init(&g_nodeGraph, &exciteNodeConfig, NULL, &g_exciteNode);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize excite node.");
+        goto done3;
+    }
+
+    ma_node_attach_output_bus(&g_exciteNode, 0, &g_vocoderNode, 1);
+
+
+    ma_device_start(&device);
+
+    printf("Press Enter to quit...\n");
+    getchar();
+
+    /* It's important that we stop the device first or else we'll uninitialize the graph from under the device. */
+    ma_device_stop(&device);
+
+/*done4:*/ ma_data_source_node_uninit(&g_exciteNode, NULL);
+done3: ma_data_source_node_uninit(&g_sourceNode, NULL);
+done2: ma_vocoder_node_uninit(&g_vocoderNode, NULL);
+done1: ma_node_graph_uninit(&g_nodeGraph, NULL);
+done0: ma_device_uninit(&device);
+
+    (void)argc;
+    (void)argv;
+    return 0;
+}

research/_extras/nodes/ma_vocoder_node/ma_vocoder_node.c

+
+#define VOCLIB_IMPLEMENTATION
+#include "ma_vocoder_node.h"
+
+static void ma_vocoder_node_process_pcm_frames(ma_node* pNode, const float** ppFramesIn, ma_uint32* pFrameCountIn, float** ppFramesOut, ma_uint32* pFrameCountOut)
+{
+    ma_vocoder_node* pVocoderNode = (ma_vocoder_node*)pNode;
+
+    (void)pFrameCountIn;
+
+    voclib_process(&pVocoderNode->voclib, ppFramesIn[0], ppFramesIn[1], ppFramesOut[0], *pFrameCountOut);
+}
+
+static ma_node_vtable g_ma_vocoder_node_vtable =
+{
+    ma_vocoder_node_process_pcm_frames,
+    NULL,
+    2,  /* 2 input channels. */
+    1,  /* 1 output channel. */
+    0
+};
+
+MA_API ma_vocoder_node_config ma_vocoder_node_config_init(ma_uint32 channels, ma_uint32 sampleRate)
+{
+    ma_vocoder_node_config config;
+
+    MA_ZERO_OBJECT(&config);
+    config.nodeConfig     = ma_node_config_init();   /* Input and output channels will be set in ma_vocoder_node_init(). */
+    config.channels       = channels;
+    config.sampleRate     = sampleRate;
+    config.bands          = 16;
+    config.filtersPerBand = 6;
+
+    return config;
+}
+
+
+
+MA_API ma_result ma_vocoder_node_init(ma_node_graph* pNodeGraph, const ma_vocoder_node_config* pConfig, const ma_allocation_callbacks* pAllocationCallbacks, ma_vocoder_node* pVocoderNode)
+{
+    ma_result result;
+    ma_node_config baseConfig;
+
+    if (pVocoderNode == NULL) {
+        return MA_INVALID_ARGS;
+    }
+
+    MA_ZERO_OBJECT(pVocoderNode);
+
+    if (pConfig == NULL) {
+        return MA_INVALID_ARGS;
+    }
+
+    if (voclib_initialize(&pVocoderNode->voclib, (unsigned char)pConfig->bands, (unsigned char)pConfig->filtersPerBand, (unsigned int)pConfig->sampleRate, (unsigned char)pConfig->channels) == 0) {
+        return MA_INVALID_ARGS;
+    }
+
+    baseConfig = pConfig->nodeConfig;
+    baseConfig.vtable = &g_ma_vocoder_node_vtable;
+    baseConfig.inputChannels[0] = pConfig->channels;    /* Source/carrier. */
+    baseConfig.inputChannels[1] = 1;                    /* Excite/modulator. Must always be single channel. */
+    baseConfig.outputChannels[0] = pConfig->channels;   /* Output channels is always the same as the source/carrier. */
+    baseConfig.outputChannels[1] = 0;                   /* Unused. */
+
+    result = ma_node_init(pNodeGraph, &baseConfig, pAllocationCallbacks, &pVocoderNode->baseNode);
+    if (result != MA_SUCCESS) {
+        return result;
+    }
+
+    return MA_SUCCESS;
+}
+
+MA_API void ma_vocoder_node_uninit(ma_vocoder_node* pVocoderNode, const ma_allocation_callbacks* pAllocationCallbacks)
+{
+    /* The base node must always be initialized first. */
+    ma_node_uninit(pVocoderNode, pAllocationCallbacks);
+}

research/_extras/nodes/ma_vocoder_node/ma_vocoder_node.h

+/* Include ma_vocoder_node.h after miniaudio.h */
+#ifndef ma_vocoder_node_h
+#define ma_vocoder_node_h
+
+#include "voclib.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct
+{
+    ma_node_config nodeConfig;
+    ma_uint32 channels;         /* The number of channels of the source, which will be the same as the output. Must be 1 or 2. The excite bus must always have one channel. */
+    ma_uint32 sampleRate;
+    ma_uint32 bands;            /* Defaults to 16. */
+    ma_uint32 filtersPerBand;   /* Defaults to 6. */
+} ma_vocoder_node_config;
+
+MA_API ma_vocoder_node_config ma_vocoder_node_config_init(ma_uint32 channels, ma_uint32 sampleRate);
+
+
+typedef struct
+{
+    ma_node_base baseNode;
+    voclib_instance voclib;
+} ma_vocoder_node;
+
+MA_API ma_result ma_vocoder_node_init(ma_node_graph* pNodeGraph, const ma_vocoder_node_config* pConfig, const ma_allocation_callbacks* pAllocationCallbacks, ma_vocoder_node* pVocoderNode);
+MA_API void ma_vocoder_node_uninit(ma_vocoder_node* pVocoderNode, const ma_allocation_callbacks* pAllocationCallbacks);
+
+#ifdef __cplusplus
+}
+#endif
+#endif  /* ma_vocoder_node_h */