Proposal: Native support for background audio "ducking" in media player announcements

[sgeorge83]

Context: I have been using a custom shell script in my home lab to create a "Morning Blessing" routine where music plays for 55 seconds, then lowers in volume (ducks) for a TTS announcement, and stops after a 5-second trail.

Problem: Currently, the media_player.play_announcement service is "interruptive." It usually stops the music to play the voice. There is no native way to layer audio or handle volume ramping (ducking) without complex custom scripts.

Proposed Solution: Add optional parameters to the play_announcement service:

• background_media_id: A track to play behind the voice.
• ducking_level: The volume percentage for the background track during the announcement (e.g., 20%).
• pre_announcement_delay: Time before the voice starts.
• post_announcement_delay: Time before the audio fades out.

This elevates the "Premium Aesthetic" of Home Assistant notifications, making them feel more professional and less jarring for daily routines.