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Comprehensive Guide to Configuring CasparCG and Decklink Cards

July 31, 2024

CasparCG is a versatile and powerful broadcasting software that can be customized to meet a wide range of production needs. One of its most compelling features is its ability to integrate with Decklink cards for professional-quality video output. In this comprehensive guide, we’ll walk you through the steps to configure CasparCG, set up Decklink cards, and establish key and fill outputs for chroma keying and other advanced effects.

1. Setting Up CasparCG Configuration

Introduction to CasparCG Configuration:

CasparCG configuration is managed through an XML file named casparcg.config. This file allows you to customize various settings such as channels, outputs, and formats to tailor CasparCG to your specific needs.

Step-by-Step Configuration:

  1. Locate the Configuration File:

    After installing CasparCG, navigate to the directory where CasparCG is installed. The casparcg.config file is typically found in the root directory.

  2. Open the Configuration File:

    Open casparcg.config using a text editor (e.g., Notepad++ on Windows, nano or vim on Linux).

  3. Basic Configuration Settings: 
    
      <configuration>
        <log-level>info</log-level>
        <channel-grid>false</channel-grid>
      </configuration>
            
    
      <channels>
        <channel>
          <video-mode>1080i5000</video-mode>
          <consumers>
            <screen/>
            <system-audio/>
          </consumers>
        </channel>
      </channels>
            
    
      <paths>
        <media-path>media/</media-path>
        <log-path>log/</log-path>
        <data-path>data/</data-path>
        <template-path>template/</template-path>
      </paths>
  4. Advanced Configuration: 
    
      <channels>
        <channel>
          <video-mode>1080i5000</video-mode>
          <consumers>
            <screen/>
            <system-audio/>
            <decklink>
              <device>1</device>
              <embedded-audio>false</embedded-audio>
              <latency>normal</latency>
              <keyer>external</keyer>
              <key-only>false</key-only>
              <buffer-depth>3</buffer-depth>
              <custom-allocator>true</custom-allocator>
            </decklink>
          </consumers>
        </channel>
      </channels>
  5. Save and Close:

    Save the changes to casparcg.config and close the text editor.

    6. 2. Setting Up Decklink Cards

    Introduction to Decklink Cards:

    Decklink cards from Blackmagic Design are widely used in professional broadcasting for high-quality video input and output. CasparCG supports Decklink cards, enabling seamless integration with your broadcast setup.

    Step-by-Step Setup:

    1. Install Decklink Drivers:

      Download and install the latest Decklink drivers from the Blackmagic Design website.

    2. Verify Installation:

      Open the Blackmagic Desktop Video Setup application to ensure the Decklink card is recognized and configured correctly.

    3. Configure Decklink in CasparCG: 
      
      <channels>
        <channel>
          <video-mode>1080i5000</video-mode>
          <consumers>
            <decklink>
              <device>1</device>
              <embedded-audio>true</embedded-audio>
              <latency>normal</latency>
              <keyer>external</keyer>
              <key-only>false</key-only>
              <buffer-depth>3</buffer-depth>
              <custom-allocator>true</custom-allocator>
            </decklink>
          </consumers>
        </channel>
      </channels>
    4. Save and Close:

      Save the changes to casparcg.config and restart the CasparCG Server to apply the new settings.

    3. Setting Up Key and Fill Outputs

    Introduction to Key and Fill:

    Key and fill outputs are used to separate the main video signal (fill) from the transparency information (key), which is crucial for chroma keying and other compositing techniques in live production.

    Step-by-Step Setup:

    1. Enable External Keyer: 
      
      <decklink>
        <device>1</device>
        <embedded-audio>true</embedded-audio>
        <latency>normal</latency>
        <keyer>external</keyer>
        <key-only>false</key-only>
        <buffer-depth>3</buffer-depth>
        <custom-allocator>true</custom-allocator>
      </decklink>
    2. Configure Decklink for Key and Fill:

      Ensure the Decklink card is set to output both key and fill signals. This typically requires configuration within the Blackmagic Desktop Video Setup application, where you can designate one output for fill and another for key.

    3. CasparCG Server Configuration:

      Make sure the CasparCG Server is set up to handle key and fill outputs properly. This involves verifying that the channel's configuration in casparcg.config correctly references the Decklink device and is set for external keying.

    4. Testing Key and Fill:

      Test the setup by playing a clip or template with alpha channel information. Verify that the fill signal outputs the video while the key signal outputs the transparency information.

    5. Example Test Command: 
      PLAY 1-1 test_with_alpha.mp4
    6. Verify Outputs:

      Use monitoring tools or hardware to verify that the Decklink outputs are correctly delivering the key and fill signals to your mixer or production switcher.

    Conclusion

    Setting up CasparCG and Decklink cards involves configuring the casparcg.config file, installing the necessary drivers, and ensuring that both key and fill outputs are properly configured for your production needs. By following this comprehensive guide, you'll be able to leverage the full capabilities of CasparCG and Decklink cards, creating professional-quality broadcasts with seamless integration and dynamic visual effects. Stay tuned for more tips and tutorials on maximizing your CasparCG setup!

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