Creating a custom Linux-based speaker that appears as a Google Chromecast device is technically feasible, but there are several important aspects to consider:
mDNS and DIAL Protocols: You are correct that Chromecast relies on mDNS for discovery and DIAL for launching applications. Implementing these protocols will allow your device to be detected by Google Cast-enabled apps.
Receiver Implementation: You can create a receiver that mimics the behavior of a Chromecast receiver. This involves implementing the Cast Application Framework (CAF) to handle media playback commands and other functionalities.
CAF Receiver: You can build a custom receiver using the Cast SDK. This receiver will need to handle various media types and control protocols (like play, pause, stop) similar to official devices.
Development: You'll need to implement the necessary APIs defined by Google, which may include handling messages and media information sent from sender apps.
Google Licensing: To officially integrate with Google Cast services, you must comply with Google's licensing and certification requirements. This often includes: Registering your device with Google. Passing certification tests to ensure compatibility with Google Cast standards. Whitelisting: Google typically requires devices to be whitelisted. This means you may need to go through a formal application process to have your device recognized as a valid Google Cast receiver. 4. Additional Considerations
Compliance: Ensure you adhere to Google’s branding and operational guidelines to avoid potential legal issues.
Community and Resources: Leverage existing open-source projects or communities that have worked on similar integrations. There are repositories and forums that can provide guidance.
Steps to Implement
Set Up mDNS: Implement mDNS on your Linux device to announce itself as a Chromecast receiver.
Implement DIAL: Set up the DIAL protocol for launching applications on your device.
Develop CAF Receiver: Follow the CAF documentation to create a receiver that can handle media playback and communication with sender apps.
Testing: Test extensively with various Google Cast-enabled apps to ensure compatibility.
Certification Process: Once your device is operational, begin the certification process with Google.