DYNAMIC_DURATION_GUIDE

Dynamic Duration Feature - Complete Guide

The news manager now includes intelligent dynamic duration calculation that automatically determines the exact time needed to display all your selected headlines without cutting off mid-scroll.

How It Works

Automatic Calculation

The system calculates the perfect display duration by:

1. Measuring Text Width: Calculates the exact pixel width of all headlines combined
2. Computing Scroll Distance: Determines how far text needs to scroll (display width + text width)
3. Calculating Time: Uses scroll speed and delay to compute exact timing
4. Adding Buffer: Includes configurable buffer time for smooth transitions
5. Applying Limits: Ensures duration stays within your min/max preferences

Real-World Example

With current settings (4 feeds, 2 headlines each):

• Total Headlines: 8 headlines per cycle
• Estimated Duration: 57 seconds
• Cycles per Hour: ~63 cycles
• Result: Perfect timing, no cut-offs

Configuration Options

Core Settings

{
  "news_manager": {
    "dynamic_duration": true,        // Enable/disable feature
    "min_duration": 30,              // Minimum display time (seconds)
    "max_duration": 300,             // Maximum display time (seconds)  
    "duration_buffer": 0.1,          // Buffer time (10% extra)
    "headlines_per_feed": 2,         // Headlines from each feed
    "scroll_speed": 2,               // Pixels per frame
    "scroll_delay": 0.02             // Seconds per frame
  }
}

Duration Scenarios

Scenario	Headlines	Est. Duration	Cycles/Hour
Light	4 headlines	30s (min)	120
Medium	6 headlines	30s (min)	120
Current	8 headlines	57s	63
Heavy	12 headlines	85s	42
Maximum	20+ headlines	300s (max)	12

Benefits

Perfect Timing

• No Cut-offs: Headlines never cut off mid-sentence
• Complete Cycles: Always shows full rotation of all selected content
• Smooth Transitions: Buffer time prevents jarring switches

Intelligent Scaling

• Adapts to Content: More feeds = longer duration automatically
• User Control: Set your preferred min/max limits
• Flexible: Works with any combination of feeds and headlines

Predictable Behavior

• Consistent Experience: Same content always takes same time
• Reliable Cycling: Know exactly when content will repeat
• Configurable: Adjust to your viewing preferences

Usage Examples

Command Line Testing

# Test dynamic duration calculations
python3 test_dynamic_duration.py

# Check current status
python3 test_dynamic_duration.py status

Configuration Changes

# Add more feeds (increases duration)
python3 add_custom_feed_example.py add "Tennis" "https://www.atptour.com/en/rss/news"

# Check new duration
python3 test_dynamic_duration.py status

Web Interface

1. Go to http://display-ip:5001
2. Click "News Manager" tab
3. Adjust "Duration Settings":
   • Min Duration: Shortest acceptable cycle time
   • Max Duration: Longest acceptable cycle time
   • Buffer: Extra time for smooth transitions

Advanced Configuration

Fine-Tuning Duration

{
  "min_duration": 45,      // Increase for longer minimum cycles
  "max_duration": 180,     // Decrease for shorter maximum cycles
  "duration_buffer": 0.15  // Increase buffer for more transition time
}

Scroll Speed Impact

{
  "scroll_speed": 3,       // Faster scroll = shorter duration
  "scroll_delay": 0.015    // Less delay = shorter duration
}

Content Control

{
  "headlines_per_feed": 3, // More headlines = longer duration
  "enabled_feeds": [       // More feeds = longer duration
    "NFL", "NBA", "MLB", "NHL", "BBC F1", "Tennis"
  ]
}

Troubleshooting

Duration Too Short

• Increase min_duration
• Add more feeds or headlines per feed
• Decrease scroll_speed

Duration Too Long

• Decrease max_duration
• Remove some feeds
• Reduce headlines_per_feed
• Increase scroll_speed

Jerky Transitions

• Increase duration_buffer
• Adjust scroll_delay

Disable Dynamic Duration

To use fixed timing instead:

{
  "dynamic_duration": false,
  "fixed_duration": 60      // Fixed 60-second cycles
}

Technical Details

Calculation Formula

total_scroll_distance = display_width + text_width
frames_needed = total_scroll_distance / scroll_speed
base_time = frames_needed * scroll_delay
buffer_time = base_time * duration_buffer
final_duration = base_time + buffer_time (within min/max limits)

Display Integration

The display controller automatically:

1. Calls news_manager.get_dynamic_duration()
2. Uses returned value for display timing
3. Switches to next mode after exact calculated time
4. Logs duration decisions for debugging

Best Practices

1. Start Conservative: Use default settings initially
2. Test Changes: Use test script to preview duration changes
3. Monitor Performance: Watch for smooth transitions
4. Adjust Gradually: Make small changes to settings
5. Consider Viewing: Match duration to your typical viewing patterns

The dynamic duration feature ensures your news ticker always displays complete, perfectly-timed content cycles regardless of how many feeds or headlines you configure!