Add live audio transcription streaming support to Foundry Local C# SDK

samples/cs/LiveAudioTranscription/LiveAudioTranscription.csproj

@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\sdk_v2\cs\src\Microsoft.AI.Foundry.Local.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.9" />
+    <PackageReference Include="NAudio" Version="2.2.1" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <!-- Copy Core + ORT native DLLs to output directory.
+       These must be placed in the project root before building.
+       See README.md for instructions. -->
+  <ItemGroup>
+    <None Include="Microsoft.AI.Foundry.Local.Core.dll" CopyToOutputDirectory="PreserveNewest" Condition="Exists('Microsoft.AI.Foundry.Local.Core.dll')" />
+    <None Include="onnxruntime-genai.dll" CopyToOutputDirectory="PreserveNewest" Condition="Exists('onnxruntime-genai.dll')" />
+    <None Include="onnxruntime.dll" CopyToOutputDirectory="PreserveNewest" Condition="Exists('onnxruntime.dll')" />
+    <None Include="onnxruntime_providers_shared.dll" CopyToOutputDirectory="PreserveNewest" Condition="Exists('onnxruntime_providers_shared.dll')" />
+  </ItemGroup>
+
+</Project>

samples/cs/LiveAudioTranscription/Program.cs

@@ -0,0 +1,169 @@
+// Live Audio Transcription — Foundry Local SDK Example
+//
+// Demonstrates real-time microphone-to-text using:
+//   SDK (FoundryLocalManager) → Core (NativeAOT DLL) → onnxruntime-genai (StreamingProcessor)
+//
+// Prerequisites:
+//   1. Nemotron ASR model downloaded to a local cache folder
+//   2. Microsoft.AI.Foundry.Local.Core.dll (built from neutron-server with GenAI 0.13.0+)
+//   3. onnxruntime-genai.dll + onnxruntime.dll + onnxruntime_providers_shared.dll (native GenAI)
+//
+// Usage:
+//   dotnet run -- [model-cache-dir]
+//   dotnet run -- C:\path\to\models
+
+using Microsoft.AI.Foundry.Local;
+using Microsoft.Extensions.Logging;
+using NAudio.Wave;
+
+// Parse model cache directory from args or use default
+var modelCacheDir = args.Length > 0
+    ? args[0]
+    : Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+                    "FoundryLocal", "models");
+
+var coreDllPath = Path.Combine(AppContext.BaseDirectory, "Microsoft.AI.Foundry.Local.Core.dll");
+
+var loggerFactory = LoggerFactory.Create(b => b.AddConsole().SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Information));
+var logger = loggerFactory.CreateLogger("LiveAudioTranscription");
+
+Console.WriteLine("===========================================================");
+Console.WriteLine("   Foundry Local -- Live Audio Transcription Demo");
+Console.WriteLine("===========================================================");
+Console.WriteLine();
+Console.WriteLine($"  Model cache: {modelCacheDir}");
+Console.WriteLine($"  Core DLL:    {coreDllPath} (exists: {File.Exists(coreDllPath)})");
+Console.WriteLine();
+
+try
+{
+    // === Step 1: Initialize Foundry Local SDK ===
+    Console.WriteLine("[1/5] Initializing Foundry Local SDK...");
+    var config = new Configuration
+    {
+        AppName = "LiveAudioTranscription",
+        LogLevel = Microsoft.AI.Foundry.Local.LogLevel.Information,
+        ModelCacheDir = modelCacheDir,
+        AdditionalSettings = new Dictionary<string, string>
+        {
+            { "FoundryLocalCorePath", coreDllPath }
+        }
+    };
+
+    await FoundryLocalManager.CreateAsync(config, logger);
+    Console.WriteLine("       SDK initialized.");
+
+    // === Step 2: Find and load the nemotron ASR model ===
+    Console.WriteLine("[2/5] Loading nemotron model...");
+    var catalog = await FoundryLocalManager.Instance.GetCatalogAsync();
+    var model = await catalog.GetModelAsync("nemotron");
+
+    if (model == null)
+    {
+        Console.WriteLine("ERROR: 'nemotron' not found in catalog.");
+        Console.WriteLine($"       Ensure the model is downloaded to: {modelCacheDir}");
+        Console.WriteLine("       The folder should contain genai_config.json, encoder.onnx, decoder.onnx, etc.");
+        return;
+    }
+
+    Console.WriteLine($"       Found model: {model.Alias}");
+    await model.LoadAsync();
+    Console.WriteLine("       Model loaded.");
+
+    // === Step 3: Create live transcription session ===
+    Console.WriteLine("[3/5] Creating live transcription session...");
+    var audioClient = await model.GetAudioClientAsync();
+    var session = audioClient.CreateLiveTranscriptionSession();
+    session.Settings.SampleRate = 16000;
+    session.Settings.Channels = 1;
+    session.Settings.Language = "en";
+
+    await session.StartAsync();
+    Console.WriteLine("       Session started (SDK -> Core -> GenAI pipeline active).");
+
+    // === Step 4: Set up microphone + transcription reader ===
+    Console.WriteLine("[4/5] Setting up microphone...");
+
+    // Background task reads transcription results as they arrive
+    var readTask = Task.Run(async () =>
+    {
+        try
+        {
+            await foreach (var result in session.GetTranscriptionStream())
+            {
+                if (result.IsFinal)
+                {
+                    Console.WriteLine();
+                    Console.WriteLine($"  [FINAL] {result.Text}");
+                    Console.Out.Flush();
+                }
+                else if (!string.IsNullOrEmpty(result.Text))
+                {
+                    Console.ForegroundColor = ConsoleColor.Cyan;
+                    Console.Write(result.Text);
+                    Console.ResetColor();
+                    Console.Out.Flush();
+                }
+            }
+        }
+        catch (OperationCanceledException) { }
+    });
+
+    // Microphone capture via NAudio
+    using var waveIn = new WaveInEvent
+    {
+        WaveFormat = new WaveFormat(rate: 16000, bits: 16, channels: 1),
+        BufferMilliseconds = 100
+    };
+
+    int totalChunks = 0;
+    long totalBytes = 0;
+
+    waveIn.DataAvailable += (sender, e) =>
+    {
+        if (e.BytesRecorded > 0)
+        {
+            _ = session.AppendAsync(new ReadOnlyMemory<byte>(e.Buffer, 0, e.BytesRecorded));
+            totalChunks++;
+            totalBytes += e.BytesRecorded;
+        }
+    };
+
+    // === Step 5: Record ===
+    Console.WriteLine();
+    Console.WriteLine("===========================================================");
+    Console.WriteLine("  LIVE TRANSCRIPTION ACTIVE");
+    Console.WriteLine("  Speak into your microphone.");
+    Console.WriteLine("  Transcription appears in real-time (cyan text).");
+    Console.WriteLine("  Press ENTER to stop recording.");
+    Console.WriteLine("===========================================================");
+    Console.WriteLine();
+
+    waveIn.StartRecording();
+    Console.ReadLine();
+    waveIn.StopRecording();
+
+    var totalSeconds = totalBytes / (16000.0 * 2);
+    Console.WriteLine($"\n  Recording: {totalSeconds:F1}s | {totalChunks} chunks | {totalBytes / 1024} KB");
+
+    // Stop session (flushes remaining audio through the pipeline)
+    Console.WriteLine("\n[5/5] Stopping session...");
+    await session.StopAsync();
+    await readTask;
+
+    // Unload model
+    await model.UnloadAsync();
+
+    Console.WriteLine();
+    Console.WriteLine("===========================================================");
+    Console.WriteLine("  Demo complete!");
+    Console.WriteLine("  Pipeline: Mic -> NAudio -> SDK -> Core -> GenAI -> Text");
+    Console.WriteLine("===========================================================");
+}
+catch (Exception ex)
+{
+    Console.WriteLine($"\nERROR: {ex.Message}");
+    if (ex.InnerException != null)
+        Console.WriteLine($"Inner: {ex.InnerException.Message}");
+    Console.WriteLine($"\n{ex.StackTrace}");
+}

samples/cs/LiveAudioTranscription/README.md

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+# Live Audio Transcription Demo
+
+Real-time microphone-to-text using Foundry Local SDK, Core, and onnxruntime-genai.
+
+## Architecture
+
+```
+Microphone (NAudio, 16kHz/16-bit/mono)
+    |
+    v
+Foundry Local SDK (C#)
+    | AppendAsync(pcmBytes)
+    v
+Foundry Local Core (NativeAOT DLL)
+    | AppendAudioChunk -> CommitTranscription
+    v
+onnxruntime-genai (StreamingProcessor + Generator)
+    | RNNT encoder + decoder
+    v
+Live transcription text
+```
+
+## Prerequisites
+
+1. **Windows x64** with a microphone
+2. **.NET 9.0 SDK** installed
+3. **Nemotron ASR model** downloaded locally
+4. **Native DLLs** (4 files — see Setup below)
+
+## Setup (Step by Step)
+
+### Step 1: Get the native DLLs
+
+You need 4 DLLs placed in this project folder:
+
+| DLL | Source |
+|-----|--------|
+| `Microsoft.AI.Foundry.Local.Core.dll` | Built from neutron-server (`dotnet publish` with NativeAOT) |
+| `onnxruntime-genai.dll` | Built from onnxruntime-genai (Nenad's StreamingProcessor branch) |
+| `onnxruntime.dll` | Comes with the Core publish output |
+| `onnxruntime_providers_shared.dll` | Comes with the Core publish output |
+
+**Option A: From CI artifacts**
+- Download the Core DLL from the neutron-server CI pipeline artifacts
+- Download the GenAI native DLLs from the onnxruntime-genai pipeline artifacts
+
+**Option B: From a teammate**
+- Ask for the 4 DLLs from someone who has already built them
+
+Copy all 4 DLLs to this folder (`samples/cs/LiveAudioTranscription/`).
+
+### Step 2: Get the Nemotron model
+
+The model should be in a folder with this structure:
+```
+models/
+  nemotron/
+    genai_config.json
+    encoder.onnx
+    decoder.onnx
+    joint.onnx
+    tokenizer.json
+    vocab.txt
+```
+
+### Step 3: Build
+
+```powershell
+cd samples/cs/LiveAudioTranscription
+dotnet build -c Debug
+```
+
+### Step 4: Copy native DLLs to output (if not auto-copied)
+
+```powershell
+Copy-Item onnxruntime-genai.dll bin\Debug\net9.0\win-x64\ -Force
+Copy-Item onnxruntime.dll bin\Debug\net9.0\win-x64\ -Force
+Copy-Item onnxruntime_providers_shared.dll bin\Debug\net9.0\win-x64\ -Force
+Copy-Item Microsoft.AI.Foundry.Local.Core.dll bin\Debug\net9.0\win-x64\ -Force
+```
+
+### Step 5: Run
+
+```powershell
+# Default model cache location
+dotnet run -c Debug --no-build
+
+# Or specify model cache directory
+dotnet run -c Debug --no-build -- C:\path\to\models
+```
+
+### Step 6: Speak!
+
+- The app will show `LIVE TRANSCRIPTION ACTIVE`
+- Speak into your microphone
+- Text appears in **cyan** as you speak
+- Press **ENTER** to stop
+
+## Expected Output
+
+```
+===========================================================
+   Foundry Local -- Live Audio Transcription Demo
+===========================================================
+
+[1/5] Initializing Foundry Local SDK...
+       SDK initialized.
+[2/5] Loading nemotron model...
+       Found model: nemotron
+       Model loaded.
+[3/5] Creating live transcription session...
+       Session started (SDK -> Core -> GenAI pipeline active).
+[4/5] Setting up microphone...
+
+===========================================================
+  LIVE TRANSCRIPTION ACTIVE
+  Speak into your microphone.
+  Transcription appears in real-time (cyan text).
+  Press ENTER to stop recording.
+===========================================================
+
+Hello this is a demo of live audio transcription running entirely on device
+  [FINAL] Hello this is a demo of live audio transcription running entirely on device
+
+  Recording: 15.2s | 152 chunks | 475 KB
+
+[5/5] Stopping session...
+
+===========================================================
+  Demo complete!
+  Pipeline: Mic -> NAudio -> SDK -> Core -> GenAI -> Text
+===========================================================
+```
+
+## Troubleshooting
+
+| Error | Fix |
+|-------|-----|
+| `Core DLL not found` | Copy `Microsoft.AI.Foundry.Local.Core.dll` to project folder |
+| `nemotron not found in catalog` | Check `ModelCacheDir` points to folder containing `nemotron/` with `genai_config.json` |
+| `OgaStreamingProcessor not found` | The `onnxruntime-genai.dll` is old — rebuild from Nenad's branch or get from CI |
+| `No microphone` | Ensure a mic is connected and set as default recording device |
+| `num_mels unknown` | Fix `genai_config.json` — ASR params must be at model level, not nested under `speech` |

sdk_v2/cs/src/AssemblyInfo.cs

@@ -7,4 +7,5 @@
 using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("Microsoft.AI.Foundry.Local.Tests")]
+[assembly: InternalsVisibleTo("AudioStreamTest")]
 [assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")] // for Mock of ICoreInterop