diff --git a/readme.md b/readme.md
index 6420089..bdbeabe 100644
--- a/readme.md
+++ b/readme.md
@@ -24,6 +24,16 @@ uv run main.py test1.mkv --xcolumn 100 --output test1_column.png
 uv run main.py test1.mkv --yrow 200 --output test1_row.png
 ```
 
+**Debug Mode** - Analyze changes and generate threshold graph:
+```bash
+uv run main.py test1.mkv --xcolumn 100 --output analysis --debug
+```
+
+**Custom Threshold** - Control compression by setting change threshold:
+```bash
+uv run main.py test1.mkv --xcolumn 100 --output test1_column.png --threshold 0.01
+```
+
 ## Configure
 We use uv to handle pip dependencies. Install with:
 ```bash
@@ -38,4 +48,43 @@ uv sync
   - Output dimensions: `(total_frames, source_width, 3)`
   - Width = source video width, Height = number of frames
 
-Each column/row in the output represents one frame from the input video, showing motion over time.
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+Each column/row in the output represents one frame from the input video, showing motion over time.
+
+## Advanced Features
+
+### Change Detection & Compression
+The implementation includes intelligent change detection that discards frames with minimal visual changes, creating more compact outputs that focus on motion:
+
+- **Automatic filtering**: Only frames with significant changes are included
+- **Configurable threshold**: Use `--threshold` (0-1) to control sensitivity
+- **Compression stats**: Shows how many frames were kept vs. skipped
+
+### Debug Mode
+Use `--debug` to analyze your video and determine optimal threshold values:
+
+```bash
+uv run main.py video.mp4 --xcolumn 500 --output analysis --debug
+```
+
+This generates:
+- **Change graph**: Visual plot of frame-to-frame changes over time
+- **Statistics**: Mean, max, min, and standard deviation of changes
+- **Threshold suggestions**: Recommended values with compression ratios
+
+### Threshold Selection Guide
+- **0.001-0.005**: High sensitivity, keeps most motion (10-30% compression)
+- **0.005-0.02**: Medium sensitivity, good balance (30-70% compression)
+- **0.02-0.1**: Low sensitivity, only major changes (70-95% compression)
+- **>0.1**: Very low sensitivity, minimal frames (95%+ compression)
+
+### Examples with Compression
+
+Extract with 75% compression (recommended starting point):
+```bash
+uv run main.py video.mp4 --xcolumn 320 --output compressed.png --threshold 0.01
+```
+
+Maximum compression for detecting only major scene changes:
+```bash
+uv run main.py video.mp4 --xcolumn 320 --output minimal.png --threshold 0.05
+```
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