|
| 1 | +# Temporal Video Tracking with V-JEPA 2 |
| 2 | + |
| 3 | +## Overview |
| 4 | + |
| 5 | +This document describes the temporal video tracking system in SOWLv2 that addresses the limitation of detecting objects only in the first frame. The system uses V-JEPA 2 for intelligent frame selection, OWLv2 for multi-frame detection, and SAM2 for consistent object tracking throughout the video. |
| 6 | + |
| 7 | +## Problem Solved |
| 8 | + |
| 9 | +Traditional video processing pipelines often: |
| 10 | +- Only detect objects in the first frame |
| 11 | +- Miss objects that appear later in the video |
| 12 | +- Process every frame (computationally expensive) |
| 13 | +- Lack temporal understanding of object motion |
| 14 | + |
| 15 | +Our temporal tracking solution: |
| 16 | +- Detects objects across multiple key frames |
| 17 | +- Uses V-JEPA 2 to identify the most informative frames |
| 18 | +- Merges detections to track unique objects |
| 19 | +- Maintains consistent object IDs throughout the video |
| 20 | + |
| 21 | +## Architecture |
| 22 | + |
| 23 | +### Key Components |
| 24 | + |
| 25 | +1. **V-JEPA 2 Frame Selection** |
| 26 | + - Analyzes entire video for temporal importance |
| 27 | + - Combines feature variance and motion analysis |
| 28 | + - Selects N most informative frames with temporal diversity |
| 29 | + |
| 30 | +2. **Multi-Frame Detection** |
| 31 | + - Runs OWLv2 on selected key frames |
| 32 | + - Detects objects that may appear at different times |
| 33 | + - Maintains detection confidence scores |
| 34 | + |
| 35 | +3. **Temporal Detection Merging** |
| 36 | + - Associates same objects across frames using IoU |
| 37 | + - Creates unified tracked objects |
| 38 | + - Selects best detection for SAM2 initialization |
| 39 | + |
| 40 | +4. **Intelligent Resource Management** |
| 41 | + - Dynamic batch size optimization |
| 42 | + - Model caching with memory management |
| 43 | + - Adaptive processing based on GPU resources |
| 44 | + |
| 45 | +## Implementation Details |
| 46 | + |
| 47 | +### New Modules |
| 48 | + |
| 49 | +#### 1. Temporal Detection (`temporal_detection.py`) |
| 50 | +Handles multi-frame object tracking logic: |
| 51 | +```python |
| 52 | +@dataclass |
| 53 | +class TemporalDetection: |
| 54 | + frame_idx: int |
| 55 | + box: List[float] |
| 56 | + score: float |
| 57 | + core_prompt: str |
| 58 | + sam_id: Optional[int] = None |
| 59 | + |
| 60 | +@dataclass |
| 61 | +class TrackedObject: |
| 62 | + object_id: int |
| 63 | + core_prompt: str |
| 64 | + detections: List[TemporalDetection] |
| 65 | + color: Tuple[int, int, int] |
| 66 | + best_detection_idx: int |
| 67 | +``` |
| 68 | + |
| 69 | +#### 2. Model Cache (`model_cache.py`) |
| 70 | +Intelligent model memory management: |
| 71 | +```python |
| 72 | +class IntelligentModelCache: |
| 73 | + def load_model_lazy(self, model_name, loader_func) |
| 74 | + def optimize_for_video_batch(self, num_frames, models_needed) |
| 75 | +``` |
| 76 | + |
| 77 | +#### 3. Batch Optimizer (`batch_optimizer.py`) |
| 78 | +Dynamic batch size optimization: |
| 79 | +```python |
| 80 | +class IntelligentBatchOptimizer: |
| 81 | + def profile_and_optimize(self, image_size, num_prompts) -> BatchConfig |
| 82 | + def adaptive_batch_processing(self, items, process_func) |
| 83 | +``` |
| 84 | + |
| 85 | +### Enhanced V-JEPA 2 Integration |
| 86 | + |
| 87 | +The V-JEPA 2 optimizer now includes motion-aware scoring: |
| 88 | +```python |
| 89 | +def get_motion_aware_importance_scores( |
| 90 | + self, |
| 91 | + frames: List[Image.Image], |
| 92 | + motion_weight: float = 0.5 |
| 93 | +) -> Optional[List[float]] |
| 94 | +``` |
| 95 | + |
| 96 | +This combines: |
| 97 | +- Feature variance (what V-JEPA 2 sees as important) |
| 98 | +- Motion detection (frame differences) |
| 99 | +- Weighted combination for optimal frame selection |
| 100 | + |
| 101 | +## Usage |
| 102 | + |
| 103 | +### Command Line Interface |
| 104 | + |
| 105 | +Basic temporal detection: |
| 106 | +```bash |
| 107 | +python -m sowlv2.cli \ |
| 108 | + --input video.mp4 \ |
| 109 | + --prompt "person" "car" \ |
| 110 | + --output output_dir \ |
| 111 | + --enable-vjepa2 \ |
| 112 | + --use-temporal-detection \ |
| 113 | + --temporal-detection-frames 10 |
| 114 | +``` |
| 115 | + |
| 116 | +Advanced configuration: |
| 117 | +```bash |
| 118 | +python -m sowlv2.cli \ |
| 119 | + --input video.mp4 \ |
| 120 | + --prompt "cat" \ |
| 121 | + --output output_dir \ |
| 122 | + --enable-vjepa2 \ |
| 123 | + --use-temporal-detection \ |
| 124 | + --temporal-detection-frames 15 \ |
| 125 | + --temporal-merge-threshold 0.6 \ |
| 126 | + --batch-size 8 \ |
| 127 | + --max-workers 4 |
| 128 | +``` |
| 129 | + |
| 130 | +### Configuration Parameters |
| 131 | + |
| 132 | +- `--temporal-detection-frames`: Number of key frames to analyze (default: 5) |
| 133 | +- `--temporal-merge-threshold`: IoU threshold for object merging (default: 0.7) |
| 134 | +- `--use-temporal-detection`: Enable the temporal detection system |
| 135 | + |
| 136 | +### Programmatic Usage |
| 137 | + |
| 138 | +```python |
| 139 | +from sowlv2.optimizations import OptimizedSOWLv2Pipeline, create_vjepa2_optimizer |
| 140 | +from sowlv2.data.config import PipelineBaseData |
| 141 | + |
| 142 | +# Configure pipeline |
| 143 | +config = PipelineBaseData( |
| 144 | + owl_model="google/owlv2-base-patch16-ensemble", |
| 145 | + sam_model="facebook/sam2.1-hiera-small", |
| 146 | + threshold=0.1, |
| 147 | + device="cuda" |
| 148 | +) |
| 149 | + |
| 150 | +# Create and configure pipeline |
| 151 | +pipeline = OptimizedSOWLv2Pipeline(config) |
| 152 | +pipeline.vjepa2_optimizer = create_vjepa2_optimizer(config) |
| 153 | +pipeline.use_temporal_detection = True |
| 154 | +pipeline.temporal_detection_frames = 10 |
| 155 | +pipeline.temporal_merge_threshold = 0.7 |
| 156 | + |
| 157 | +# Process video |
| 158 | +pipeline.process_video("input.mp4", ["person", "bicycle"], "output/") |
| 159 | +``` |
| 160 | + |
| 161 | +## Processing Flow |
| 162 | + |
| 163 | +1. **Frame Extraction**: Extract all frames from video at specified FPS |
| 164 | +2. **Temporal Analysis**: V-JEPA 2 analyzes frames for importance scores |
| 165 | +3. **Frame Selection**: Select N most informative frames with temporal spacing |
| 166 | +4. **Multi-Frame Detection**: Run OWLv2 on each selected frame |
| 167 | +5. **Detection Merging**: Associate and merge detections across frames |
| 168 | +6. **SAM2 Initialization**: Initialize tracking with best detection per object |
| 169 | +7. **Video Processing**: Propagate masks throughout entire video |
| 170 | + |
| 171 | +## Performance Optimization |
| 172 | + |
| 173 | +### Memory Management |
| 174 | +- Lazy model loading |
| 175 | +- Automatic memory cleanup when threshold exceeded |
| 176 | +- Pre-allocation for video batches |
| 177 | + |
| 178 | +### Batch Processing |
| 179 | +- Dynamic batch sizing based on GPU memory |
| 180 | +- Adaptive adjustment during processing |
| 181 | +- Mixed precision support for compatible GPUs |
| 182 | + |
| 183 | +### Example Performance |
| 184 | +``` |
| 185 | +Traditional approach (1000 frames): |
| 186 | +- Detects in frame 1 only |
| 187 | +- Misses objects appearing later |
| 188 | +- Time: ~300s |
| 189 | + |
| 190 | +Temporal detection (1000 frames): |
| 191 | +- Analyzes 10 key frames |
| 192 | +- Detects all objects throughout video |
| 193 | +- Time: ~120s |
| 194 | +- Better coverage with less computation |
| 195 | +``` |
| 196 | + |
| 197 | +## Best Practices |
| 198 | + |
| 199 | +### Parameter Tuning |
| 200 | + |
| 201 | +1. **Number of Detection Frames** |
| 202 | + - Short videos (< 30s): 5-10 frames |
| 203 | + - Medium videos (30s-2min): 10-20 frames |
| 204 | + - Long videos (> 2min): 20-30 frames |
| 205 | + |
| 206 | +2. **Merge Threshold** |
| 207 | + - Static scenes: 0.7-0.8 (strict matching) |
| 208 | + - Dynamic scenes: 0.5-0.6 (looser matching) |
| 209 | + - Fast motion: 0.4-0.5 (very loose) |
| 210 | + |
| 211 | +3. **Frame Spacing** |
| 212 | + - Calculated as: `len(frames) // (num_detection_frames * 2)` |
| 213 | + - Ensures temporal diversity |
| 214 | + - Prevents clustering of selected frames |
| 215 | + |
| 216 | +### Troubleshooting |
| 217 | + |
| 218 | +**Issue**: Out of memory errors |
| 219 | +- Solution: Reduce `temporal-detection-frames` |
| 220 | +- Solution: Lower batch size |
| 221 | +- Solution: Use CPU processing |
| 222 | + |
| 223 | +**Issue**: Missed objects |
| 224 | +- Solution: Increase `temporal-detection-frames` |
| 225 | +- Solution: Lower detection `threshold` |
| 226 | +- Solution: Check V-JEPA 2 frame selection |
| 227 | + |
| 228 | +**Issue**: Duplicate detections |
| 229 | +- Solution: Increase `temporal-merge-threshold` |
| 230 | +- Solution: Check IoU calculation |
| 231 | +- Solution: Verify prompt matching |
| 232 | + |
| 233 | +## Technical Advantages |
| 234 | + |
| 235 | +1. **Comprehensive Detection**: Objects detected throughout video, not just first frame |
| 236 | +2. **Intelligent Processing**: Only processes most informative frames |
| 237 | +3. **Robust Tracking**: Maintains object consistency across frames |
| 238 | +4. **Resource Efficient**: Adaptive resource management |
| 239 | +5. **Scalable**: Works on videos of any length |
| 240 | + |
| 241 | +## Future Enhancements |
| 242 | + |
| 243 | +1. **Adaptive Frame Selection**: Automatically determine optimal number of frames |
| 244 | +2. **Motion Prediction**: Use V-JEPA 2 to predict object trajectories |
| 245 | +3. **Real-time Processing**: Streaming video support |
| 246 | +4. **Multi-GPU Support**: Distribute processing across GPUs |
| 247 | +5. **Confidence Weighting**: Use detection confidence in merging decisions |
| 248 | + |
| 249 | +## References |
| 250 | + |
| 251 | +- [V-JEPA 2 Paper](https://arxiv.org/abs/2404.08471) |
| 252 | +- [OWLv2 Model](https://huggingface.co/google/owlv2-base-patch16-ensemble) |
| 253 | +- [SAM2 Documentation](https://github.com/facebookresearch/sam2) |
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