docs: update readme with new parameters and defaults

- Document all new CLI parameters (--relax, auto-output)
- Add smart defaults section (yrow=8, auto-generated filenames)
- Include usage examples for relax feature
- Document output organization (results/ vs results/debug/)
- Add PowerShell batch command example from debug mode
- Update parameter descriptions with current behavior

Also: Set --relax default to 100 when flag used without value

readme.md

@@ -12,16 +12,35 @@ Strip photography records a moving scene over time by extracting the same line p
 
 ## Usage
 
-**Row Mode** - Extract horizontal lines with threshold filtering:
+**Basic Usage** - Uses smart defaults (yrow=8, auto output to results/):
 ```bash
-uv run main.py .\line500fps32pix.mp4 --yrow 16 --output demo.jpg --threshold 0.005
+uv run main.py .\line500fps32pix.mp4
+```
+Output: `results/line500fps32pix_a3f2_t0_01.jpg` (auto-generated with UUID and threshold)
+
+**Row Mode** - Extract horizontal lines with custom settings:
+```bash
+uv run main.py .\line500fps32pix.mp4 --yrow 16 --threshold 0.005
+```
+
+**With Relax** - Include extra frames around threshold frames for smoother transitions:
+```bash
+uv run main.py .\line500fps32pix.mp4 --relax 5
+# or use default relax value (100):
+uv run main.py .\line500fps32pix.mp4 --relax
 ```
 
 **Debug Mode** - Analyze changes and generate threshold recommendations:
 ```bash
-uv run main.py .\line500fps32pix.mp4 --yrow 16 --output demo.jpg --debug
+uv run main.py .\line500fps32pix.mp4 --debug
+```
+Output: `results/debug/line500fps32pix_7c91_t0_01_changes.png`
+![debug view](demo_changes2.jpg)
+
+Debug mode generates PowerShell commands to test all suggested thresholds:
+```powershell
+0.0087,0.0098,0.0112,0.0121,0.0159 | %{uv run .\main.py video.mp4 --threshold $_}
 ```
-![debug view](demo_changes.png)
 
 ## Setup
 Install dependencies with uv:
@@ -29,18 +48,45 @@ Install dependencies with uv:
 uv sync
 ```
 
-## Output Modes
+## Parameters
+
+### Required
+- `video_file` - Path to input video file
+
+### Optional
+- `--xcolumn N` - Extract vertical line at x-coordinate (column mode)
+- `--yrow N` - Extract horizontal line at y-coordinate (row mode, **default: 8**)
+- `--output PATH` - Output file path (default: auto-generated to `results/` with UUID)
+- `--threshold N` - Change threshold 0-1 for frame inclusion (default: 0.01)
+- `--relax [N]` - Include N extra frames before/after threshold frames (default: 0, or 100 if flag used without value)
+- `--debug` - Analyze changes without creating strip image, outputs to `results/debug/`
+
+### Output Modes
 - **Column mode**: Extracts vertical line (`--xcolumn`) → Width = frames, Height = video height
-- **Row mode**: Extracts horizontal line (`--yrow`) → Width = video width, Height = frames
+- **Row mode**: Extracts horizontal line (`--yrow`, **default**) → Rotated 90° CW for proper orientation
 
 ## Features
 
+**Smart Defaults**:
+- Defaults to row mode at y=8 if no mode specified
+- Auto-generates output filename with UUID and threshold: `results/video_a3f2_t0_01.jpg`
+- Automatically appends `.jpg` extension if none provided
+- Row mode output is rotated 90° clockwise for proper viewing
+
 **Change Detection**: Automatically filters frames with minimal changes using configurable thresholds
 - Use `--threshold` (0-1) to control sensitivity
 - `--debug` mode provides threshold recommendations and change analysis
 - Higher thresholds = more compression, fewer frames
 
+**Relax Feature**: Include extra frames around significant changes for smoother transitions
+- `--relax 5` includes 5 frames before/after each threshold frame
+- `--relax` without value defaults to 100 frames
+
 **Threshold Guide**:
 - `0.001-0.005`: High sensitivity (10-30% compression)
 - `0.005-0.02`: Medium sensitivity (30-70% compression)
 - `0.02+`: Low sensitivity (70%+ compression)
+
+**Output Organization**:
+- Normal mode: `results/` folder
+- Debug mode: `results/debug/` folder