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m3ultra bb542960c2 Lane B (M2 + M8 geometry): COLMAP reconstruction, geometry math, graceful degradation
Implements spec M2 (frame sampling, COLMAP orchestration, TXT-model parsing, scene
normalization, pose interpolation, PLY + DB export) and the M8 geometry functions.

geometry.py (M8): slerp_pose (shortest-arc, double-cover), ray_from_pixel (COLMAP
+y-down back-projection), triangulate_rays (closest-point + parallel guard),
nearest_point_on_ray (in-front radius cylinder). Frozen colmap_to_threejs untouched.

frames.py (M2): variance-of-Laplacian sharpness + windowed sharpest-frame sampling.

sfm.py (M2): hand-written COLMAP images/cameras/points3D parsers; normalize_scene
(centroid->0, camera sphere r->10, up->+Y) as one similarity transform over points+poses;
interpolate_poses (slerp+lerp, no extrapolation); build-aware COLMAP CLI orchestration
(3.x/4.x option detection, CPU SIFT, single-camera-per-folder, undistort->TXT, largest
component by images.bin header count); run_reconstruct with full graceful degradation
(COLMAP absent / <60% / <2 videos / no frames / missing files -> poses left untouched).

Tests: 61 pass (24 foundation + 37 lane-B) with independent oracles (scipy Slerp,
projection-inverse, closed-form geometry) and every degradation/DB-safety branch covered.
Validated end-to-end against real COLMAP 4.1.0 (6 components, largest selected, weak ->
graceful degradation, exit 0).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-16 08:40:46 +10:00
backend Lane B (M2 + M8 geometry): COLMAP reconstruction, geometry math, graceful degradation 2026-07-16 08:40:46 +10:00
frontend Foundation (M0 + M3 + frozen contracts): scaffold, synthetic fixtures, full API 2026-07-16 00:45:55 +10:00
plan Lane B (M2 + M8 geometry): COLMAP reconstruction, geometry math, graceful degradation 2026-07-16 08:40:46 +10:00
.gitignore Festival 4D build spec + parallel lane plan for Opus agents 2026-07-16 00:06:54 +10:00
OPUS_BUILD_INSTRUCTIONS.md Festival 4D build spec + parallel lane plan for Opus agents 2026-07-16 00:06:54 +10:00
pyproject.toml Foundation (M0 + M3 + frozen contracts): scaffold, synthetic fixtures, full API 2026-07-16 00:45:55 +10:00
README.md Foundation (M0 + M3 + frozen contracts): scaffold, synthetic fixtures, full API 2026-07-16 00:45:55 +10:00
uv.lock Foundation (M0 + M3 + frozen contracts): scaffold, synthetic fixtures, full API 2026-07-16 00:45:55 +10:00

Festival 4D

Turn multiple fan-shot smartphone videos of the same concert into a synchronized, explorable 4D experience: time-aligned multi-video playback, 3D scene reconstruction with camera poses, a free-roam "god's eye" viewer, AR-style overlays projected onto each video, and AI-tagged moments on a shared timeline.

Status: foundation phase. The scaffold, database, frozen contracts (API, pose math, DB schema), and a synthetic fixture generator are in place. Feature lanes (media sync, reconstruction, viewer, AI events) build on top. The full README with the real-footage workflow is written in the integration phase (M9). See OPUS_BUILD_INSTRUCTIONS.md for the canonical spec and plan/ for the execution plan.

Prerequisites

  • Python 3.11+ and uv (or venv + pip)
  • ffmpeg / ffprobe on your PATH (required)
  • COLMAP (optional — reconstruction degrades gracefully without it)
  • A classifier API key (optional — GEMINI_API_KEY by default; see events_ai.py)
  • Node 18+ for the frontend

Quickstart (synthetic demo — no footage needed)

# 1. backend env
uv venv --python 3.12
uv pip install -e ".[dev]"

# 2. generate the synthetic fixture project (fake videos + poses + point cloud + events)
uv run python -m festival4d synthetic

# 3. serve the API (http://127.0.0.1:8000)
uv run python -m festival4d serve

# 4. in another terminal, the frontend
cd frontend
npm install
npm run dev            # http://localhost:5173

Backend CLI

python -m festival4d synthetic     # generate the synthetic fixture (M0)
python -m festival4d ingest        # probe videos + extract audio      (lane A / M1)
python -m festival4d sync          # GCC-PHAT audio alignment           (lane A / M1)
python -m festival4d reconstruct   # COLMAP SfM + pose export           (lane B / M2)
python -m festival4d events        # audio candidates + AI classify     (lane D / M7)
python -m festival4d serve         # FastAPI app                        (M3)

Tests

uv run pytest