libobs, win-wasapi: Enable channel routing for Audio Input Capture

libobs/media-io/audio-resampler-ffmpeg.c

@@ -216,3 +216,27 @@ bool audio_resampler_resample(audio_resampler_t *rs, uint8_t *output[], uint32_t
 	*out_frames = (uint32_t)ret;
 	return true;
 }
+
+// Allows passing of a matrix for channel re-ordering and custom weights.
+bool audio_resampler_set_matrix(audio_resampler_t *rs, double *matrix, int stride)
+{
+	if (!rs) {
+		return false;
+	}
+
+	swr_close(rs->context);
+
+	if (swr_set_matrix(rs->context, matrix, stride) < 0) {
+		blog(LOG_DEBUG, "swr_set_matrix failed\n");
+		audio_resampler_destroy(rs);
+		return false;
+	}
+
+	int errcode = swr_init(rs->context);
+	if (errcode != 0) {
+		blog(LOG_ERROR, "swr_init failed: error code %d", errcode);
+		audio_resampler_destroy(rs);
+		return false;
+	}
+	return true;
+}

libobs/media-io/audio-resampler.h

@@ -39,6 +39,8 @@ EXPORT void audio_resampler_destroy(audio_resampler_t *resampler);
 EXPORT bool audio_resampler_resample(audio_resampler_t *resampler, uint8_t *output[], uint32_t *out_frames,
 				     uint64_t *ts_offset, const uint8_t *const input[], uint32_t in_frames);
 
+EXPORT bool audio_resampler_set_matrix(audio_resampler_t *rs, double *matrix, int stride);
+
 #ifdef __cplusplus
 }
 #endif

plugins/mac-capture/data/locale/en-US.ini

@@ -8,6 +8,7 @@ CoreAudio.Channel.Unnamed="Unnamed"
 CoreAudio.Channel.Device="Device Channel"
 CoreAudio.None="None"
 CoreAudio.Downmix="Enable Downmixing"
+CoreAudio.Downmix.Hint="By default OBS will automatically upmix or downmix to the number of channels configured in settings. Enabling this setting will allow you to manually select which channels of the device to map to the input in OBS."
 ApplicationCapture="Application Capture"
 ApplicationAudioCapture="Application Audio Capture"
 DesktopAudioCapture="Desktop Audio Capture"

plugins/mac-capture/mac-audio.c

@@ -1015,6 +1015,7 @@ static obs_properties_t *coreaudio_properties(bool input, void *data)
 	obs_property_set_modified_callback2(property, coreaudio_device_changed, ca);
 
 	property = obs_properties_add_bool(props, "enable_downmix", obs_module_text("CoreAudio.Downmix"));
+	obs_property_set_long_description(property, obs_module_text("CoreAudio.Downmix.Hint"));
 	obs_property_set_modified_callback2(property, coreaudio_downmix_changed, ca);
 
 	if (ca != NULL && ca->au_initialized) {

plugins/win-wasapi/data/locale/en-US.ini

@@ -9,3 +9,14 @@ Priority="Window Match Priority"
 Priority.Title="Window title must match"
 Priority.Class="Match title, otherwise find window of same type"
 Priority.Exe="Match title, otherwise find window of same executable"
+Routing="Enable Channel Routing"
+Routing.Hint="By default OBS will automatically upmix or downmix to the number of channels configured in settings.\nEnabling this setting will allow you to manually select which channels of the device to map to the input in OBS."
+OBS_channel.0="OBS Channel 1"
+OBS_channel.1="OBS Channel 2"
+OBS_channel.2="OBS Channel 3"
+OBS_channel.3="OBS Channel 4"
+OBS_channel.4="OBS Channel 5"
+OBS_channel.5="OBS Channel 6"
+OBS_channel.6="OBS Channel 7"
+OBS_channel.7="OBS Channel 8"
+None="None"

plugins/win-wasapi/enum-wasapi.cpp

@@ -1,6 +1,7 @@
 #include "enum-wasapi.hpp"
 
 #include <util/base.h>
+#include <util/bmem.h>
 #include <util/platform.h>
 #include <util/windows/HRError.hpp>
 #include <util/windows/ComPtr.hpp>
@@ -34,6 +35,26 @@ string GetDeviceName(IMMDevice *device)
 	return device_name;
 }
 
+std::string GetWASAPIDefaultDeviceName(bool input)
+{
+	ComPtr<IMMDeviceEnumerator> enumerator;
+	ComPtr<IMMDevice> device;
+
+	HRESULT res = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_ALL, __uuidof(IMMDeviceEnumerator),
+				       (void **)enumerator.Assign());
+	if (FAILED(res)) {
+		return "";
+	}
+
+	res = enumerator->GetDefaultAudioEndpoint(input ? eCapture : eRender, input ? eCommunications : eConsole,
+						  device.Assign());
+	if (FAILED(res)) {
+		return "";
+	}
+
+	return GetDeviceName(device);
+}
+
 static void GetWASAPIAudioDevices_(vector<AudioDeviceInfo> &devices, bool input)
 {
 	ComPtr<IMMDeviceEnumerator> enumerator;
@@ -90,3 +111,45 @@ void GetWASAPIAudioDevices(vector<AudioDeviceInfo> &devices, bool input)
 		blog(LOG_WARNING, "[GetWASAPIAudioDevices] %s: %lX", error.str, error.hr);
 	}
 }
+
+int GetWASAPIDeviceInputChannels(const char *device_id)
+{
+	ComPtr<IMMDeviceEnumerator> enumerator;
+	ComPtr<IMMDevice> device;
+	ComPtr<IAudioClient> client;
+	CoTaskMemPtr<WAVEFORMATEX> wfex;
+
+	HRESULT res =
+		CoCreateInstance(__uuidof(MMDeviceEnumerator), nullptr, CLSCTX_ALL, IID_PPV_ARGS(enumerator.Assign()));
+	if (FAILED(res)) {
+		return 0;
+	}
+
+	if (strcmp(device_id, "default") == 0) {
+		res = enumerator->GetDefaultAudioEndpoint(eCapture, eCommunications, device.Assign());
+	} else {
+		wchar_t *w_id = nullptr;
+		os_utf8_to_wcs_ptr(device_id, strlen(device_id), &w_id);
+		if (!w_id) {
+			return 0;
+		}
+		res = enumerator->GetDevice(w_id, device.Assign());
+		bfree(w_id);
+	}
+
+	if (FAILED(res) || !device) {
+		return 0;
+	}
+
+	res = device->Activate(__uuidof(IAudioClient), CLSCTX_ALL, nullptr, (void **)client.Assign());
+	if (FAILED(res)) {
+		return 0;
+	}
+
+	res = client->GetMixFormat(&wfex);
+	if (FAILED(res) || !wfex) {
+		return 0;
+	}
+
+	return wfex->nChannels;
+}

plugins/win-wasapi/enum-wasapi.hpp

@@ -38,4 +38,6 @@ struct AudioDeviceInfo {
 };
 
 std::string GetDeviceName(IMMDevice *device);
+std::string GetWASAPIDefaultDeviceName(bool input);
 void GetWASAPIAudioDevices(std::vector<AudioDeviceInfo> &devices, bool input);
+int GetWASAPIDeviceInputChannels(const char *device_id);