StreamLens/FRAME_REFERENCE_FIX_SUMMARY.md

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!