Audio Ads

This guide covers how AdCP represents audio advertising formats for streaming audio, podcasts, and radio.

Audio Format Characteristics

Audio formats include:

• Hosted Audio - Direct audio file URLs (MP3, M4A)
• VAST Audio - DAAST/VAST tags for programmatic audio
• With Companion Banners - Audio + synchronized display companion
• Podcast Insertion - Dynamic ad insertion (DAI) for podcasts

Audio ads are typically non-skippable and play during natural content breaks.

Standard Audio Formats

Streaming Audio (15s, 30s, 60s)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "audio_30s"
  },
  "type": "audio",
  "assets_required": [
    {
      "asset_id": "audio_file",
      "asset_type": "audio",
      "asset_role": "hero_audio",
      "required": true,
      "requirements": {
        "duration": "30s",
        "format": ["MP3", "M4A"],
        "bitrate_min": "128kbps",
        "max_file_size_mb": 5
      }
    }
  ]
}

Audio with Companion Banner

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "audio_30s_companion"
  },
  "type": "audio",
  "assets_required": [
    {
      "asset_id": "audio_file",
      "asset_type": "audio",
      "asset_role": "hero_audio",
      "required": true,
      "requirements": {
        "duration": "30s",
        "format": ["MP3", "M4A"],
        "bitrate_min": "128kbps"
      }
    },
    {
      "asset_id": "companion_banner",
      "asset_type": "image",
      "asset_role": "companion_banner",
      "required": false,
      "requirements": {
        "width": 640,
        "height": 640,
        "file_types": ["jpg", "png", "webp"],
        "notes": "Displays during audio playback on screen-enabled devices"
      }
    }
  ]
}

Podcast Mid-Roll (60s)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "podcast_midroll_60s"
  },
  "type": "audio",
  "assets_required": [
    {
      "asset_id": "audio_file",
      "asset_type": "audio",
      "asset_role": "hero_audio",
      "required": true,
      "requirements": {
        "duration": "60s",
        "format": ["MP3", "M4A"],
        "bitrate_min": "128kbps",
        "max_file_size_mb": 10
      }
    }
  ]
}

Dynamic Audio Creative (DAC)

Multi-segment audio assembled dynamically:

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "audio_dynamic_30s"
  },
  "type": "audio",
  "assets_required": [
    {
      "asset_id": "intro_audio",
      "asset_type": "audio",
      "asset_role": "intro",
      "required": true,
      "requirements": {
        "duration": "5s",
        "format": ["MP3"]
      }
    },
    {
      "asset_id": "product_audio",
      "asset_type": "audio",
      "asset_role": "product_message",
      "required": true,
      "requirements": {
        "duration": "15s",
        "format": ["MP3"]
      }
    },
    {
      "asset_id": "cta_audio",
      "asset_type": "audio",
      "asset_role": "call_to_action",
      "required": true,
      "requirements": {
        "duration": "10s",
        "format": ["MP3"]
      }
    }
  ],
  "delivery": {
    "method": "server_side_stitching"
  }
}

Creative Manifests

Hosted Audio Manifest

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "audio_30s"
  },
  "assets": {
    "audio_file": {
      "asset_type": "audio",
      "url": "https://cdn.brand.com/audio_spring_30s.mp3",
      "duration": 30,
      "format": "audio/mpeg"
    },
    "impression_tracker": {
      "asset_type": "url",
      "url_type": "tracker",
      "url": "https://track.brand.com/imp?buy={MEDIA_BUY_ID}&station={APP_BUNDLE}&cb={CACHEBUSTER}"
    },
    "landing_url": {
      "asset_type": "url",
      "url_type": "clickthrough",
      "url": "https://brand.com/spring?campaign={MEDIA_BUY_ID}"
    }
  }
}

VAST Audio Tag Manifest

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "audio_30s_vast"
  },
  "assets": {
    "vast_url": {
      "asset_type": "url",
      "url_type": "tracker",
      "url": "https://ad-server.brand.com/audio-vast?campaign={MEDIA_BUY_ID}&cb={CACHEBUSTER}"
    }
  }
}

Audio with Companion Banner Manifest

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "audio_30s_companion"
  },
  "assets": {
    "audio_file": {
      "asset_type": "audio",
      "url": "https://cdn.brand.com/audio_spring_30s.mp3",
      "duration": 30,
      "format": "audio/mpeg"
    },
    "companion_banner": {
      "asset_type": "image",
      "url": "https://cdn.brand.com/companion_640x640.jpg",
      "width": 640,
      "height": 640
    },
    "landing_url": {
      "asset_type": "url",
      "url_type": "clickthrough",
      "url": "https://brand.com/spring-sale?source=audio&cb={CACHEBUSTER}"
    }
  }
}

Audio-Specific Macros

In addition to universal macros, audio formats support:

Content Context

• {CONTENT_GENRE} - podcast, music, news, talk
• {CONTENT_RATING} - Explicit, Clean
• {SHOW_NAME} - Podcast or show name
• {EPISODE_ID} - Episode identifier
• {ARTIST_NAME} - Currently playing artist (music platforms)
• {TRACK_GENRE} - Music genre of current track

Platform Context

• {APP_BUNDLE} - Streaming app ID (Spotify, Apple Music, etc.)
• {STATION_ID} - Radio station ID
• {LISTENING_MODE} - Free tier, Premium, Trial
• {DEVICE_TYPE} - Mobile, Desktop, Smart Speaker, Auto

Ad Insertion

• {INSERTION_TYPE} - preroll, midroll, postroll
• {TIME_OF_DAY} - morning, afternoon, evening, night
• {DAY_PART} - Commute, Workout, Work, Relaxation

Platform-Specific Requirements

Streaming Music (Spotify, Pandora, Apple Music)

• Free tier: Non-skippable audio between songs
• Typical durations: 15s or 30s
• Optional companion banner on screen-enabled devices

Podcast Insertion

• Baked-in: Permanently encoded in episode
• Dynamic insertion (SSAI): Personalized, with targeting and reporting

Companion Banners

Appear alongside audio on screen-enabled devices:

• Mobile apps, desktop players, smart speakers with displays
• Common sizes: 640x640 (square), 320x50 (mobile banner)

Common File Specifications

Audio Files

• Format: MP3 or M4A
• Bitrate: Minimum 128kbps, recommended 192kbps
• Sample Rate: 44.1kHz or 48kHz
• Channels: Stereo or mono

Durations

• 15s: Quick message, high frequency
• 30s: Standard, most common
• 60s: Story-driven, common in podcasts

Related Documentation

• Universal Macros - Complete macro reference
• Creative Manifests - Manifest structure and validation
• Asset Types - Audio asset specifications