How It Works
Use when user wants to change the overall audio mix or apply a preset. Preset names: documentary, podcast, music_video, cinematic, social_short, news_broadcast, silent_bgm_only, voiceover_only, interview, tutorial, gaming, asmr, wedding, corporate. If user says 'make it sound like a podcast' -> preset='podcast'. If user gives custom volumes like 'voice at 80, music at 20' -> vo_volume=80, bgm_volume=20.