Fix screen mirroring audio: native FDK-AAC decoder, buffer overflow fix, CI packaging

.github/workflows/build.yml

@@ -31,6 +31,47 @@ jobs:
     - name: Publish
       run: dotnet publish AirPlay/AirPlay.csproj --configuration Release --runtime win-x64 --self-contained true --output ./publish/win-x64
 
+    - name: Download FFmpeg
+      shell: pwsh
+      run: |
+        $ffmpegUrl = "https://github.com/BtbN/FFmpeg-Builds/releases/download/latest/ffmpeg-master-latest-win64-gpl.zip"
+        Invoke-WebRequest -Uri $ffmpegUrl -OutFile ffmpeg.zip
+        Expand-Archive -Path ffmpeg.zip -DestinationPath ffmpeg-tmp
+        # Copy ffmpeg.exe and ffplay.exe to publish directory
+        $binDir = Get-ChildItem -Path ffmpeg-tmp -Recurse -Directory -Filter "bin" | Select-Object -First 1
+        Copy-Item "$($binDir.FullName)\ffmpeg.exe" -Destination ./publish/win-x64/
+        Copy-Item "$($binDir.FullName)\ffplay.exe" -Destination ./publish/win-x64/
+
+    - name: Build libfdk-aac from source
+      shell: bash
+      run: |
+        # Build FDK-AAC from official source using MSYS2 (pre-installed on windows-latest)
+        export MSYSTEM=MINGW64
+        export PATH="/c/msys64/mingw64/bin:/c/msys64/usr/bin:$PATH"
+
+        # Install build dependencies
+        pacman -S --noconfirm --needed mingw-w64-x86_64-gcc mingw-w64-x86_64-cmake make
+
+        # Clone and build fdk-aac
+        git clone --depth 1 https://github.com/mstorsjo/fdk-aac.git fdk-aac-src
+        cd fdk-aac-src
+
+        # Use CMake for a simpler build
+        mkdir build && cd build
+        cmake -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON ..
+        cmake --build . --config Release
+
+        # Find and copy the DLL
+        echo "Built files:"
+        find . -name "*.dll" -type f
+        DLL_PATH=$(find . -name "fdk-aac*.dll" -o -name "libfdk-aac*.dll" | head -1)
+        if [ -z "$DLL_PATH" ]; then
+          echo "ERROR: No FDK-AAC DLL found after build"
+          exit 1
+        fi
+        cp -v "$DLL_PATH" ../../publish/win-x64/libfdk-aac-2.dll
+        echo "Successfully built and copied libfdk-aac-2.dll"
+
     - name: Upload build artifacts
       uses: actions/upload-artifact@v4
       with:

AirPlay/AirPlayService.cs

@@ -147,8 +147,21 @@ public async Task StartAsync(CancellationToken cancellationToken)
             };
 
             _audiobuf = new List<byte>();
+            int pcmReceivedCount = 0;
             _airPlayReceiver.OnPCMDataReceived += (s, e) =>
             {
+                pcmReceivedCount++;
+                if (pcmReceivedCount <= 5 || pcmReceivedCount % 500 == 0)
+                {
+                    bool allZeros = true;
+                    int checkLen = Math.Min(e.Length, 100);
+                    for (int i = 0; i < checkLen; i++)
+                    {
+                        if (e.Data[i] != 0) { allZeros = false; break; }
+                    }
+                    Console.WriteLine($"[DEBUG-PCM] OnPCMDataReceived #{pcmReceivedCount}: len={e.Length}, allZeros={allZeros}");
+                }
+
                 // Play audio through speakers
                 lock (_audioOutputLock)
                 {