# Frame Reference Fix Summary

## Issue Resolution
Fixed timing outlier detection to properly track frame references within subflows.

## Root Causes Identified and Fixed:

### 1. Race Conditions in Parallel Processing ✅ FIXED
- **Issue**: Multi-threaded background processing caused frame references to get mixed up
- **Symptom**: Frame 2002 showing previous frame 298 instead of 1998
- **Fix**: Changed BackgroundAnalyzer from `num_threads=4` to `num_threads=1`
- **Files**: `background_analyzer.py`, `app_v2.py`

### 2. Frame Classification Splitting Related Frames ✅ FIXED
- **Issue**: Similar CH10 frames were being classified into different frame types
- **Symptom**: Frame 486 showing previous frame 471 instead of 485 (frame 485 was CH10-Multi-Source)
- **Fix**: Modified frame classification to group similar CH10 timing frames as CH10-Data
- **Files**: `flow_manager.py`

### 3. Extended Timing Frames Excluded from Data Stream ✅ FIXED
- **Issue**: Extended Timing frames were classified separately despite having same ~100ms timing
- **Symptom**: Frame 476 showing previous frame 471 instead of 475 (frame 475 was CH10-Extended)
- **Fix**: Removed separate CH10-Extended classification, grouped with CH10-Data
- **Files**: `flow_manager.py`

## Technical Implementation:

### Enhanced Outlier Tracking
- Added `enhanced_outlier_details: List[Tuple[int, int, float]]` storing (frame_num, prev_frame_num, delta_t)
- Updated outlier detection to populate enhanced details with correct frame references
- Modified TUI to use frame-type outliers instead of flow-level outliers

### Single-Threaded Processing
- BackgroundAnalyzer now defaults to `num_threads=1` to prevent race conditions
- TUI updated to use single-threaded analyzer
- Maintains deterministic frame processing order

### Unified Frame Classification
- CH10 frames with similar timing patterns now grouped as CH10-Data
- Only frames with significantly different timing kept separate (ACTTS, etc.)
- Ensures consecutive frames in same subflow are properly tracked

## Final Results:
- **Frame 476**: Now correctly shows "from 475" instead of "from 471"
- **Frame 486**: No longer an outlier (timing is normal in sequence)
- **Frame 957**: No longer an outlier (timing is normal in sequence)
- **Only 2 legitimate outliers remain**: Frames 1582 and 1640 with ~1100ms delays (23.2σ)

## Verification:
All frame reference validation tests pass with 🎉 **ALL FRAME REFERENCES ARE CORRECT!**