feat: initial plugin implementation

README.md

@@ -1,59 +1,73 @@
-# OBS Plugin Template
+# Mix Track to Source
 
-## Introduction
+```mermaid
+flowchart TB
+    subgraph OBS Mix tracks
+        T1["Any Track
+        from 1 to 6"]
+        T2@{ shape: procs, label: "Output Tracks" }
+    end
 
-The plugin template is meant to be used as a starting point for OBS Studio plugin development. It includes:
+    subgraph Mix Track to Source Plugin
+        subgraph P1["mt2s_callback()"]
+            P2["obs_source_output_audio()"]
+        end
 
-* Boilerplate plugin source code
-* A CMake project file
-* GitHub Actions workflows and repository actions
+        subgraph OBS Audio Mixer
+            S["Source"]
+        end
+        P2-->S
+    end
+    T1-->P1
+    S-->T2
+    S-.-x|"To avoid loopback,
+    the input track
+    cannot be output"|T1
+```
 
-## Supported Build Environments
+- Select an input mix track to create an audio source
+- The audio source uses the selected mix track as input and allows various filters to be applied
+- Allows selection of mix tracks as output, excluding the mix track selected as input
+- Buffering causes a minimum delay of 1024 samples (21 ms at 48 kHz)
+  - If even greater delay is unacceptable, enable **Low Latency Buffering Mode** in OBS Settings > Audio > Advanced
 
-| Platform  | Tool   |
-|-----------|--------|
-| Windows   | Visual Studio 17 2022 |
-| macOS     | XCode 16.0 |
-| Windows, macOS  | CMake 3.30.5 |
-| Ubuntu 24.04 | CMake 3.28.3 |
-| Ubuntu 24.04 | `ninja-build` |
-| Ubuntu 24.04 | `pkg-config`
-| Ubuntu 24.04 | `build-essential` |
+## Install
 
-## Quick Start
+Please download the archive file from the [Releases](https://github.com/semnil/MixTrack2Source/releases) page.
 
-An absolute bare-bones [Quick Start Guide](https://github.com/obsproject/obs-plugintemplate/wiki/Quick-Start-Guide) is available in the wiki.
+### Windows
 
-## Documentation
+After extracting the archive file, place the `mix-track-to-source` folder in the following location:
 
-All documentation can be found in the [Plugin Template Wiki](https://github.com/obsproject/obs-plugintemplate/wiki).
+```
+C:\ProgramData\obs-studio\plugins
+```
 
-Suggested reading to get up and running:
 
-* [Getting started](https://github.com/obsproject/obs-plugintemplate/wiki/Getting-Started)
-* [Build system requirements](https://github.com/obsproject/obs-plugintemplate/wiki/Build-System-Requirements)
-* [Build system options](https://github.com/obsproject/obs-plugintemplate/wiki/CMake-Build-System-Options)
+### macOS
 
-## GitHub Actions & CI
+Run the `mix-track-to-source-<version>-macos-universal.pkg` file to install it.
 
-Default GitHub Actions workflows are available for the following repository actions:
 
-* `push`: Run for commits or tags pushed to `master` or `main` branches.
-* `pr-pull`: Run when a Pull Request has been pushed or synchronized.
-* `dispatch`: Run when triggered by the workflow dispatch in GitHub's user interface.
-* `build-project`: Builds the actual project and is triggered by other workflows.
-* `check-format`: Checks CMake and plugin source code formatting and is triggered by other workflows.
+### Ubuntu
 
-The workflows make use of GitHub repository actions (contained in `.github/actions`) and build scripts (contained in `.github/scripts`) which are not needed for local development, but might need to be adjusted if additional/different steps are required to build the plugin.
+Run the following command:
 
-### Retrieving build artifacts
+```
+sudo dpkg -i mix-track-to-source-<version>-x86_64-linux-gnu.deb
+```
 
-Successful builds on GitHub Actions will produce build artifacts that can be downloaded for testing. These artifacts are commonly simple archives and will not contain package installers or installation programs.
 
-### Building a Release
+## Usage
 
-To create a release, an appropriately named tag needs to be pushed to the `main`/`master` branch using semantic versioning (e.g., `12.3.4`, `23.4.5-beta2`). A draft release will be created on the associated repository with generated installer packages or installation programs attached as release artifacts.
+- `Add Source` > `Mix Track` to add an audio source
+- Select a mix track to use for input from `Track 1` to `Track 6`
+- Select outputs for added audio track in the Advanced Audio Properties window
+  - Cannot select the same track for both input and output
+  - Deselect the output from other sources as needed
 
-## Signing and Notarizing on macOS
 
-Basic concepts of codesigning and notarization on macOS are explained in the correspodning [Wiki article](https://github.com/obsproject/obs-plugintemplate/wiki/Codesigning-On-macOS) which has a specific section for the [GitHub Actions setup](https://github.com/obsproject/obs-plugintemplate/wiki/Codesigning-On-macOS#setting-up-code-signing-for-github-actions).
+## Information for development
+
+Please refer to the template repository information.  
+https://github.com/obsproject/obs-plugintemplate

buildspec.json

@@ -33,13 +33,13 @@
     },
     "platformConfig": {
         "macos": {
-            "bundleId": "com.example.plugintemplate-for-obs"
+            "bundleId": "com.semnil.mix-track-to-source"
         }
     },
-    "name": "plugintemplate-for-obs",
-    "displayName": "Plugin Template for OBS",
+    "name": "mix-track-to-source",
+    "displayName": "Mix Track to Source",
     "version": "1.0.0",
-    "author": "Your Name Here",
-    "website": "https://example.com",
-    "email": "me@example.com"
+    "author": "semnil",
+    "website": "https://semnil.com",
+    "email": "info@semnil.com"
 }

data/locale/en-US.ini

@@ -0,0 +1,8 @@
+MixTrack="Mix Track"
+Input="Input"
+Track1="Track 1"
+Track2="Track 2"
+Track3="Track 3"
+Track4="Track 4"
+Track5="Track 5"
+Track6="Track 6"

data/locale/ja-JP.ini

@@ -0,0 +1,8 @@
+MixTrack="ミックストラック"
+Input="入力"
+Track1="トラック 1"
+Track2="トラック 2"
+Track3="トラック 3"
+Track4="トラック 4"
+Track5="トラック 5"
+Track6="トラック 6"

src/plugin-main.c

@@ -1,6 +1,6 @@
 /*
-Plugin Name
-Copyright (C) <Year> <Developer> <Email Address>
+Mix Track to Source
+Copyright (C) 2026 semnil info@semnil.com
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -22,8 +22,169 @@ with this program. If not, see <https://www.gnu.org/licenses/>
 OBS_DECLARE_MODULE()
 OBS_MODULE_USE_DEFAULT_LOCALE(PLUGIN_NAME, "en-US")
 
+typedef struct {
+	obs_source_t *source;
+	size_t mix_idx;
+} mt2s_context_t;
+
+void mt2s_avoid_loopback(mt2s_context_t *context, size_t mix_idx)
+{
+	// override output settings to avoid loopback
+	size_t mixers = obs_source_get_audio_mixers(context->source);
+	if (mixers != (mixers & ~(1 << mix_idx)))
+		obs_source_set_audio_mixers(context->source, mixers & ~(1 << mix_idx));
+}
+
+static void mt2s_callback(void *param, size_t mix_idx, struct audio_data *data)
+{
+	mt2s_context_t *context = (mt2s_context_t *)param;
+	if (!context || context->mix_idx != mix_idx || !data || !data->frames)
+		return;
+
+	mt2s_avoid_loopback(context, mix_idx);
+
+	struct obs_audio_info oai;
+	if (obs_get_audio_info(&oai)) {
+		// bridge data from the mix track to the audio source
+		struct obs_source_audio output_audio = {.frames = data->frames,
+							.speakers = oai.speakers,
+							.format = AUDIO_FORMAT_FLOAT_PLANAR,
+							.samples_per_sec = oai.samples_per_sec,
+							.timestamp = data->timestamp};
+
+		for (int i = 0; i < MAX_AV_PLANES; i++) {
+			output_audio.data[i] = data->data[i];
+		}
+
+		obs_source_output_audio(context->source, &output_audio);
+	}
+}
+
+void mt2s_disconnect(mt2s_context_t *context)
+{
+	if (!context || context->mix_idx >= MAX_AUDIO_MIXES)
+		return;
+
+	// disconnect the connected mix track
+	audio_output_disconnect(obs_get_audio(), context->mix_idx, mt2s_callback, context);
+	obs_log(LOG_INFO, "audio_output_disconnect(%u)", context->mix_idx);
+	// initialize the connected mix track id
+	context->mix_idx = SIZE_MAX;
+}
+
+void mt2s_connect(mt2s_context_t *context, size_t mix_idx)
+{
+	audio_t *audio = obs_get_audio();
+
+	if (context->mix_idx != mix_idx) {
+		// disconnect the connected mix track
+		mt2s_disconnect(context);
+	}
+
+	// connect the mix track
+	if (audio_output_connect(audio, mix_idx, NULL, mt2s_callback, context)) {
+		// save the connected mix track id
+		context->mix_idx = mix_idx;
+		obs_log(LOG_INFO, "audio_output_connect(%u)", context->mix_idx);
+	}
+}
+
+// lifecycle
+void *mt2s_create(obs_data_t *settings, obs_source_t *source)
+{
+	mt2s_context_t *context = malloc(sizeof(mt2s_context_t));
+
+	if (context) {
+		context->source = source;
+		context->mix_idx = SIZE_MAX;
+
+		// deselect all outputs
+		obs_source_set_audio_mixers(context->source, 0);
+
+		mt2s_connect(context, obs_data_get_int(settings, "MixTrack"));
+	}
+
+	return context;
+}
+
+void mt2s_destroy(void *data)
+{
+	if (!data)
+		return;
+
+	mt2s_context_t *context = (mt2s_context_t *)data;
+	mt2s_disconnect(context);
+	free(context);
+}
+
+void mt2s_update(void *data, obs_data_t *settings)
+{
+	if (!data || !settings)
+		return;
+
+	mt2s_context_t *context = (mt2s_context_t *)data;
+	mt2s_connect(context, obs_data_get_int(settings, "MixTrack"));
+}
+
+// configs
+const char *obs_module_name(void)
+{
+	return "Mix Track to Source";
+}
+
+const char *obs_module_description(void)
+{
+	return "Routing Mix Track to Source";
+}
+
+static const char *get_name(void *type_data)
+{
+	UNUSED_PARAMETER(type_data);
+
+	return obs_module_text("MixTrack");
+}
+
+static void get_defaults(obs_data_t *settings)
+{
+	if (!settings)
+		return;
+
+	obs_data_set_default_int(settings, "MixTrack", 0);
+}
+
+static obs_properties_t *get_properties(void *data)
+{
+	UNUSED_PARAMETER(data);
+
+	obs_properties_t *props = obs_properties_create();
+
+	obs_property_t *list = obs_properties_add_list(props, "MixTrack", obs_module_text("Input"), OBS_COMBO_TYPE_LIST,
+						       OBS_COMBO_FORMAT_INT);
+	obs_property_list_add_int(list, obs_module_text("Track1"), 0);
+	obs_property_list_add_int(list, obs_module_text("Track2"), 1);
+	obs_property_list_add_int(list, obs_module_text("Track3"), 2);
+	obs_property_list_add_int(list, obs_module_text("Track4"), 3);
+	obs_property_list_add_int(list, obs_module_text("Track5"), 4);
+	obs_property_list_add_int(list, obs_module_text("Track6"), 5);
+
+	return props;
+}
+
+// module
 bool obs_module_load(void)
 {
+	struct obs_source_info info = {.id = PLUGIN_NAME,
+				       .type = OBS_SOURCE_TYPE_INPUT,
+				       .output_flags = OBS_SOURCE_AUDIO | OBS_SOURCE_DO_NOT_DUPLICATE,
+				       .icon_type = OBS_ICON_TYPE_AUDIO_OUTPUT,
+				       .get_name = get_name,
+				       .create = mt2s_create,
+				       .destroy = mt2s_destroy,
+				       .get_defaults = get_defaults,
+				       .get_properties = get_properties,
+				       .update = mt2s_update};
+	obs_register_source(&info);
+
 	obs_log(LOG_INFO, "plugin loaded successfully (version %s)", PLUGIN_VERSION);
 	return true;
 }

src/plugin-support.c.in

@@ -1,6 +1,6 @@
 /*
-Plugin Name
-Copyright (C) <Year> <Developer> <Email Address>
+Mix Track to Source
+Copyright (C) 2026 semnil info@semnil.com
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by

src/plugin-support.h

@@ -1,6 +1,6 @@
 /*
-Plugin Name
-Copyright (C) <Year> <Developer> <Email Address>
+Mix Track to Source
+Copyright (C) 2026 semnil info@semnil.com
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by