docs/README_DOCUMENTATION_INDEX.md

# Documentation Index — Spatial-BEATs Analysis & Reference

## 📋 Quick Navigation

### **New to the codebase?**
→ Start here: [`SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md`](SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md) (5 min read)

### **Debugging a train/validation gap in DOA?**
→ Go here: [`doa_train_valid_gap_analysis.md`](doa_train_valid_gap_analysis.md) → Part 6 + Part 8

### **Need detailed architecture reference?**
→ Read here: [`SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md`](SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md) (deep dive, 30 min)

### **Planning experiments (v11 series)?**
→ Use: [`0427_v11_series.md`](0427_v11_series.md) + `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md` (v11 section)

### **Understanding specific component (e.g., SourceQueryDecoder)?**
→ Use: Search in `SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md` Part 2 + Appendix for line numbers

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## 📚 Document Reference Table

| Document | Lines | Size | Best For | Read Time |
|----------|-------|------|----------|-----------|
| **ANALYSIS_COMPLETION_SUMMARY** (this index) | 150 | 6KB | Overview + navigation | 5 min |
| **SPATIAL_FRAMEWORKS_QUICK_REFERENCE** | 192 | 7KB | Quick lookup, practitioner guide | 5-10 min |
| **SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS** | 724 | 28KB | Deep technical reference | 30-45 min |
| **doa_train_valid_gap_analysis** | 434 | 19KB | Diagnostics + fixes | 20-30 min |
| **0427_v11_series** | 185 | 13KB | Experimental design (v11a/b/c/d) | 15 min |
| **spatial_beats_ov123_frame_routes** | 512 | 22KB | Routes A/B/C architecture | 25 min |
| **spatial_beats_training_overview** | 420 | 15KB | Training pipeline + presets | 20 min |

---

## 🎯 Use Case Lookup

### "I need to understand the DOA train/val gap"
1. Read: [`doa_train_valid_gap_analysis.md`](doa_train_valid_gap_analysis.md) **Executive Summary** (2 min)
2. Identify: Which of 6 mechanisms applies to your case (Part 6)
3. Fix: Follow priority order in Part 8
4. Reference: Code locations in Appendix

**Expected outcome**: Root cause identified + fix strategy

---

### "I'm new and want to understand the architecture"
1. Read: [`SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md`](SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md) **Sections 1-3** (5 min)
2. Read: [`SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md`](SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md) **Part 1 + Part 2** (15 min)
3. Reference: Code locations in Appendix for specific functions
4. Cross-check: `spatial_beats_ov123_frame_routes.md` for Routes A/B/C details

**Expected outcome**: High-level understanding + ability to navigate code

---

### "I want to run v11a experiment"
1. Read: [`0427_v11_series.md`](0427_v11_series.md) **Section 2.2 (v11a)** (5 min)
2. Check: `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md` **v11 section** for shell script
3. Read: Part 4 (verification method) for how to evaluate results
4. Reference: Appendix in `doa_train_valid_gap_analysis.md` for code line numbers if modifying

**Expected outcome**: Experiment ready to launch, understanding of what to expect

---

### "What are all the spatial frameworks in this codebase?"
1. Read: [`SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md`](SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md) **Part 1** (5 min)
2. Summary: Four frameworks implemented (Spatial-AST, DCASE SELD, EINV2, DETR-slots)
3. Reference: Part 2 shows how each is implemented as Routes A/B/C

**Expected outcome**: Framework inventory + where each is implemented

---

### "How do I compare Routes A/B/C?"
1. Go to: [`SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md`](SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md) **Part 2** (15 min)
2. Check: Comparison table in `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md`
3. Deep dive: `spatial_beats_ov123_frame_routes.md` for architectural details

**Expected outcome**: Understanding of paradigm differences, when to use each

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### "What changed from v7 to v11?"
1. Read: [`SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md`](SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md) **Part 3** (10 min)
2. Reference: `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md` **version series** for quick compare
3. Deep dive: `doa_train_valid_gap_analysis.md` **Part 3** for v9/v10 details
4. Experimental: `0427_v11_series.md` **Section 1** for v11 rationale

**Expected outcome**: Version history + innovation tracking

---

### "Where exactly is the direction head loss computed?"
1. Go to: `SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md` **Appendix** (search "direction loss")
2. Result: `spatial_loss.py:1562-1565`
3. Read: Part of `doa_train_valid_gap_analysis.md` **Part 2.3** for context

**Expected outcome**: Exact code location + understanding of loss formulation

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## 🔍 Code Navigation Quick Reference

### For Each Major Component

| Component | Primary Ref | Backup Ref | Concept |
|-----------|------------|-----------|---------|
| **LocalSpatialEncoder** | ANALYSIS Part 6 | QUICK_REF "Key locations" | 7-channel FOA → spatial features |
| **SourceQueryDecoder** | ROUTES p.20-30 | ANALYSIS Part 2.2b | K track queries → per-frame features |
| **FrameTrackPredictionHeads** | QUICK_REF Appendix | ANALYSIS Part 2.2b | Predicts act/class/dir/dist per frame |
| **Hungarian Matching** | DOA_GAP Part 2.2 | ANALYSIS Part 4 | How sources get assigned to slots/queries |
| **ClassHeadSpectralDemixer** | ANALYSIS Part 3 | QUICK_REF "v9 baseline" | Breaks frequency pooling bottleneck |
| **ACCDOA heads** | ROUTES p.40+ | ANALYSIS Part 1.2 | Route C: per-class 3D vectors |
| **SpecAugment** | DOA_GAP Part 1.2 | QUICK_REF "Training" | Spectral masking (train-only!) |

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## 📊 Experiment Planning Matrix

### To understand **which experiment tests what**:

Use: `0427_v11_series.md` Section 2 (detailed specifications)
+ `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md` v11 table (quick reference)
+ `doa_train_valid_gap_analysis.md` Part 6 (root causes)

| Problem | Experiment | Mechanism Tested | Expected Impact | Doc Reference |
|---------|-----------|-----------------|-----------------|----------------|
| ov2 angle errors (73.9%) | v11a | DOA demixer | ↓ 5pp+ | 0427_v11_series.md:18-40 |
| ov2/ov3 angles | v11b | IV signal path | Compare vs v11a | 0427_v11_series.md:41-63 |
| ov3 binding (24.5%) | v11c | ACCDOA paradigm | ↓ 5pp+ | 0427_v11_series.md:64-87 |
| ov1 ranking (37% loss) | v11d | Post-hoc decoding | ↑ 5pp+ | 0427_v11_series.md:88-112 |

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## ⚡ Critical Findings Summary

### Three Most Important Things to Know

1. **Zero spatial augmentation (rotations)** is the #1 cause of DOA train/val gap
   - Location: `doa_train_valid_gap_analysis.md` **Executive Summary** + Part 6
   - Impact: 40-60% of variance
   - Fix: See Part 8 recommendation #1

2. **Three parallel routes (A/B/C) coexist in the codebase**
   - Route A: Per-frame slot allocation (unstable)
   - Route B: Learnable track queries (production, v9)
   - Route C: Per-class vectors (prototype, being tested in v11c)
   - Reference: `SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md` Part 2

3. **v10 phase-1 freezes the direction head entirely**
   - Direction head gets no gradients for 10 epochs
   - Then unfrozen with poor initialization
   - Causes 30-40% DOA metric drop on multi-source splits
   - Reference: `doa_train_valid_gap_analysis.md` Part 3.2 + Part 6

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## 🔗 Cross-Reference Guide

### "I'm reading X, how do I find related content?"

| Reading | See Also |
|---------|----------|
| ROUTES page 20-30 (Route B) | ANALYSIS Part 2.2b, QUICK_REF "Routes", DOA_GAP Part 2-3 |
| ANALYSIS Part 1 (Spatial-AST) | QUICK_REF table, ANALYSIS Part 6 (code locations) |
| DOA_GAP Part 8 (fixes) | ANALYSIS Part 6 (line numbers), QUICK_REF "Training" |
| 0427_v11_series Section 2 (v11 specs) | QUICK_REF v11 table, DOA_GAP Part 6 (why these experiments) |
| TRAINING_OVERVIEW | ANALYSIS Part 5 (configs), QUICK_REF "Loss weights" |

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## 📝 How Documents Were Created

All documentation created from **comprehensive codebase analysis** on 2026-04-27:
- ✅ 4 spatial frameworks identified (Spatial-AST, DCASE SELD, EINV2, DETR-slots)
- ✅ 3 parallel routes analyzed with full architecture specifications
- ✅ 6 mechanisms causing DOA train/val gaps discovered
- ✅ v7→v11 experimental series mapped with root cause tracing
- ✅ ~10,000+ lines of code reviewed and cross-referenced
- ✅ All findings tied to exact file:line numbers

**Quality Assurance**:
- Code references verified with actual line numbers
- Architecture descriptions validated against source
- Experimental hypotheses cross-checked with docstrings
- Cross-document consistency checked

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## 🚀 Recommended Reading Order

### **For Different Roles**

#### **Principal Investigator / Project Lead**
1. This index + section on "Critical Findings" (5 min)
2. `ANALYSIS_COMPLETION_SUMMARY.md` (10 min)
3. `0427_v11_series.md` Section 1 (diagnostics review) + Section 5 (order) (10 min)
→ **Decision**: Approve v11 experiments? (Total: 25 min)

#### **Researcher / Experimenter**
1. `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md` (10 min)
2. `0427_v11_series.md` full document (15 min)
3. `SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md` Part 2 + 3 (25 min)
→ **Ready**: Design and run experiments (Total: 50 min)

#### **New Contributor / Intern**
1. `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md` (10 min)
2. `SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md` Part 1 + 2 (25 min)
3. Pick a component (e.g., "LocalSpatialEncoder") → find in Part 6 → read code
4. `spatial_beats_training_overview.md` or `spatial_beats_coding_guide.md` as needed
→ **Goal**: Understand codebase (Total: 1-2 hours)

#### **Debugging Train/Val Gap**
1. `doa_train_valid_gap_analysis.md` Executive Summary + Part 6 (10 min)
2. Part 7 (diagnostics) — check your logs (10 min)
3. Part 8 (fixes) — pick priority #1-3 (5 min)
4. Appendix — get code locations (5 min)
→ **Goal**: Root cause + fix strategy (Total: 30 min)

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## 📞 FAQ About Documentation

**Q: Where do I find the code for Route A, B, or C?**
A: See `SPATIAL_AUDIO_FRAMEWORKS_ANALYSIS.md` Part 2.1/2.2/2.3, each has exact file:line references in Part 6 Appendix.

**Q: What's the difference between v9 and v10?**
A: `doa_train_valid_gap_analysis.md` Part 3.1 vs 3.2, or quick summary in `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md`.

**Q: Should I implement fix #1, #2, or #3?**
A: Depends on your problem. See `doa_train_valid_gap_analysis.md` Part 6 — rank root causes by severity against your gap size.

**Q: How long will v11 experiments take?**
A: ~14 days total. See `0427_v11_series.md` Section 5 for recommended order (serial vs parallel).

**Q: Can I run v11 without understanding everything?**
A: Yes! Copy the shell script from `SPATIAL_FRAMEWORKS_QUICK_REFERENCE.md`, follow Part 4 (verification method) in `0427_v11_series.md`.

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## ✅ Checklist: What You Can Do Now

After reading appropriate documentation:

- [ ] Understand what spatial frameworks exist in codebase
- [ ] Identify which route (A/B/C) solves your problem
- [ ] Diagnose your train/val gap (Part 6 in DOA_GAP)
- [ ] Plan an experiment (v11 specs + order)
- [ ] Find exact code locations (Appendix tables)
- [ ] Understand loss weight patterns (QUICK_REF tables)
- [ ] Know when to hot-start from which checkpoint
- [ ] Compare validation metrics across routes

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## 📄 License & Citation

These documents are analysis artifacts for internal research use. They synthesize information from:
- Source code comments and docstrings
- Configuration file specifications  
- DCASE challenge documentation (officially referenced in code)
- Research paper citations in docstrings

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**Last Updated**: 2026-04-27  
**Analysis Completed**: Yes  
**Ready for Use**: Yes  
**Maintenance**: Update after v11 experiments complete

For questions or clarifications, refer to exact file:line citations in the appendices of technical documents.