Investigate MF activation — Vortice 3.6.2 API mismatch, defer port

Added Vortice.MediaFoundation 3.6.2 NuGet package to TeamsISO.Engine so the scaffold compiles when MF_AVAILABLE is defined. However: the scaffold (May 9) was written against an older Vortice surface and the 3.6.2 API has materially changed:

- MFVersion not on MediaFactory, MF_LOW_LATENCY moved

- IMFAttributes.SetUINT32 replaced with generic Set

- IMFMediaType.MajorType / SubType / AvgBitrate property setters → SetGUID(MFAttributeKeys.MajorType, ...) etc.

- VideoFormatGuids.RGB32 renamed (likely Rgb32)

- IMFMediaBuffer.Lock signature changed (explicit out IntPtr / out int / out int)

- IMFSinkWriter.Finalize_ renamed

Leaving MF_AVAILABLE undefined for now so the build stays clean. NuGet ref stays so a porter doesn't need to re-add. docs/REAL-TIME-RECORDING.md updated with the deferred status + the specific API gaps to port.

docs/REAL-TIME-RECORDING.md

@@ -14,15 +14,36 @@ It's behind a build flag because activating it requires adding a NuGet
 dependency. The structural code is already in
 `src/TeamsISO.Engine/Pipeline/MediaFoundationRecorderSink.cs`.
 
-## Activating it
+## Status — May 2026
 
-1. **Add the NuGet dependency** to the engine project:
+**Activation deferred.** The Vortice.MediaFoundation 3.6.2 NuGet package
+is referenced from `TeamsISO.Engine.csproj`, but the `MF_AVAILABLE` symbol
+is *not* defined. The scaffold in
+`src/TeamsISO.Engine/Pipeline/MediaFoundationRecorderSink.cs` was written
+against an older Vortice API and needs a port pass before activation:
 
-       dotnet add src/TeamsISO.Engine package Vortice.MediaFoundation --version 3.6.2
+- `MFVersion` → not on `MediaFactory` in 3.6.2; pass the SDK version
+  directly to `MFStartup`.
+- `MediaFactory.MF_LOW_LATENCY` → relocated to a different attribute
+  constants class.
+- `IMFAttributes.SetUINT32` → replaced with a generic `Set` overload.
+- `IMFMediaType.MajorType` / `.SubType` / `.AvgBitrate` properties
+  → now use `SetGUID(MFAttributeKeys.MajorType, ...)` etc.
+- `VideoFormatGuids.RGB32` → renamed (likely `Rgb32`).
+- `IMFMediaBuffer.Lock(out IntPtr, out int, out int)` → explicit out-param
+  signature, no longer returns a locked-buffer wrapper.
+- `IMFSinkWriter.Finalize_` → renamed (likely `Finalize`).
 
-   (Pin to a known-good version — Vortice's API surface is stable across
-   3.6.x but the engine code targets the namespaces in 3.6.x. If a newer
-   major version changes namespaces, the file may need adjustment.)
+Until the port lands, the `RawBgraRecorderSink` is the only IRecorderSink
+production uses. The raw recorder is reliable and FFmpeg post-processing
+via the emitted `convert.cmd` produces equivalent .mp4s; you just pay the
+disk pressure during the show.
+
+## Activating it (after the port)
+
+1. **Update the scaffold** to match Vortice 3.6.2's API surface. A clean
+   reference implementation lives in the Vortice samples repo under
+   `samples/MediaFoundationSamples`.
 
 2. **Define the `MF_AVAILABLE` build symbol** in `TeamsISO.Engine.csproj`:
 

src/TeamsISO.Engine/TeamsISO.Engine.csproj

@@ -2,6 +2,15 @@
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
+    <!-- MediaFoundationRecorderSink is gated on MF_AVAILABLE — DON'T define
+         it yet. The Vortice.MediaFoundation 3.6.2 API has materially changed
+         from what the scaffold assumed (MFVersion / MF_LOW_LATENCY moved,
+         IMFMediaType lost MajorType / SubType / AvgBitrate property setters,
+         IMFMediaBuffer.Lock signature changed, Finalize_ renamed, etc.) so
+         turning it on at the source level today won't compile. Tracked as
+         a known issue in docs/REAL-TIME-RECORDING.md — when the scaffold is
+         rewritten against the 3.6.2 surface, re-add the define here. -->
+    <!-- <DefineConstants>$(DefineConstants);MF_AVAILABLE</DefineConstants> -->
   </PropertyGroup>
 
   <ItemGroup>
@@ -11,6 +20,7 @@
     <PackageReference Include="Serilog.Sinks.Console" Version="6.0.0" />
     <PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
     <PackageReference Include="System.Reactive" Version="6.0.0" />
+    <PackageReference Include="Vortice.MediaFoundation" Version="3.6.2" />
   </ItemGroup>
 
   <ItemGroup>