Mimir/docs/implementation-plan.md

# Implementation Plan

## Current Cut Line

Mimir is now a C# app/runtime plus native reservoir project. The live stream
machine must be direct-driver and native-buffer first:

- `src/Mimir.App` hosts Aquarium Engine for windowing, rendering, and the D3D12
  bridge.
- `src/Mimir.Runtime` owns stream descriptors, source polling, direct push
  ingest, one rolling buffer per configured audio/video stream, and the
  synchronization hub Aquarium can inspect.
- The default five-second window is an intentional latency/memory trade: use it
  to line up streams and extract the volumetric audio/video field before OBS
  sees program output.
- `native/reservoir` owns the lower native rolling-buffer invariant for
  Aquarium/Faust integration.
- PowerShell/FFmpeg/SRT remains a bridge utility for LAN OBS feeds. It is not
  the synchronized program authority.

The old script stack is gone. Do not add a compatibility edge unless it protects
a named invariant that the native runtime cannot protect yet.

## Implemented

- Mimir public identity, branding, and Face memory.
- `Mimir.slnx` with `src/Mimir.App` and `src/Mimir.Runtime`.
- Aquarium host bootstrapping from `Mimir.App`.
- `MimirSynchronizationHub`, `MimirRollingStreamBuffer`, stream descriptors, and
  `IMimirStreamSource`.
- Configurable five-second default rolling buffers for local and network audio
  and video streams.
- `MimirNativeIngestStreamSource` for direct push ingest into runtime buffers.
- `MimirProcessStreamSource` for bridge/network command edges.
- `MimirFrameEventProcessStreamSource` for temporary JSON-line frame metadata
  from native probes into the same rolling buffers Aquarium inspects. One probe
  process can accept multiple emitted `sourceId` values so it does not reopen
  the same camera set once per stream.
- `src/Mimir.BufferSmoke` loads the runtime config, polls the synchronization
  hub, and prints the actual rolling buffers. Use `--require-samples` when an
  empty declared sensor buffer should fail the run.
- `native/probes/wasapi_audio_cadence` captures WASAPI mic or render-loopback
  block metadata and emits `audio-block` JSON events for the diagnostic runtime
  adapter.
- `MimirChirpletTimeline` owns the structured birdsong-like calibration stream,
  PCM segment rendering, matched timing trace, and per-band response kernels.
  The default timeline is an order-3 de Bruijn symbol sequence over 32 separated
  chirp symbols, so any three consecutive correctly detected symbols identify a
  timeline event inside the current operating horizon.
- `MimirAudioSynchronizationAnalyzer` ports the first live sync measurement:
  sample-bearing audio blocks are resampled into the Scarlett loopback timeline
  and compared by chirplet-energy delay estimation with fractional peak
  interpolation. When timeline symbols are decoded, matched event indices refine
  the delay estimate and are exposed in telemetry.
- `MimirSynchronizationHub.BuildAlignedAudioFrame` exposes the first
  provisional aligned mono frame for loopback-referenced audio channels that
  clear the confidence gate.
- `MimirAudioSynchronizationStateTracker` owns the first smoothed per-source
  sync state: latest fractional delay, smoothed delay, confidence, per-band
  response evidence, and delay-slope/SRO estimate in ppm.
- `MimirRuntime` updates audio sync analysis online and can emit live sync
  telemetry with `MIMIR_SYNC_TELEMETRY_SECONDS`.
- `MimirRuntime` continuously queues chirplet timeline PCM through Aquarium
  audio so the loopback and acoustic mic buffers carry a shared timing witness.
- `MimirVideoFrameDescriptor` for dimensions, pixel format, stride, device
  timestamp, and native/GPU handle metadata.
- `IMimirVideoCaptureDriver` and `MimirVideoCaptureDriverSource` as the live
  driver-facing seam for Leap, Media Foundation, DirectShow, libusb, LeapC, or
  shared texture capture.
- `native/reservoir` with one shared-edge rolling buffer, typed views, C ABI,
  source-id hashing, producer helpers, and typed audio/render payload
  descriptors.
- Windows bridge scripts for sender discovery/start/stop and simple OBS Media
  Source ingest.
- Documentation for OBS receiver setup, native rebuild boundaries, the viable
  stream app, and the Mimir Face.

## Temporary

- Audio and video may still traverse separate OBS/SRT endpoints during bridge
  testing so OBS can preserve independent controls.
- Process-backed stream sources are only acceptable for network bridge feeds or
  diagnostics. Six-camera local ingest belongs behind direct capture drivers.
- Frame-event process sources are diagnostic only. They prove source cadence and
  runtime plumbing without dragging stdout bytes into the pixel hot loop.
- Calibration artifacts may remain on disk as evidence, but live state must be
  in memory inside Mimir/Aquarium/native runtime surfaces.

## Next

1. Replace the frame-event diagnostic bridge with concrete direct capture
   drivers for Leap stereo IR first, then the
   other cameras.
2. Feed those drivers into `MimirVideoCaptureDriverSource` and prove sustained
   frame cadence in the rolling buffers.
3. Replace the WASAPI frame-event diagnostic bridge with native audio capture
   workers for local mic, loopback, and network audio feeds.
4. Add the synchronization actuator: drive a variable-rate resampler and
   fractional delay line per non-reference stream from the smoothed
   `MimirAudioSynchronizationState`. The current aligned frame is integer-delay
   only and should not pretend to be the final DSP path.
   First, harden the online state filter so the continuous chirplet lock stops
   producing jumpy delay estimates.
5. Bind Aquarium UI to the synchronization hub so buffer depth, stream cadence,
   source timestamps, and output settings are visible and adjustable.
6. Move GPU feature extraction, fusion, material fitting, render budgeting, and
   Spout2 publication into Aquarium.
7. Move mic alignment, room suppression, voice separation, spatialization, and
   stem generation into Faust/native DSP.
8. Keep the OBS bridge witness ledger as evidence before expanding receiver
   machinery.