> ## Documentation Index
> Fetch the complete documentation index at: https://docs.viddyscribe.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Standard AD vs Extended AD

> Choose the right audio description mode for your video

## Standard AD vs Extended AD

ViddyScribe supports two audio description modes through the `ad_type` field:

| Mode        | API value     | Best for                                                     | Timing behavior                                                   |
| ----------- | ------------- | ------------------------------------------------------------ | ----------------------------------------------------------------- |
| Standard AD | `standard_ad` | Concise descriptions that fit around existing speech         | Places descriptions in natural pauses and no-speech zones.        |
| Extended AD | `extended_ad` | Fuller descriptions when the video needs more visual context | Can extend or adjust timing to make room for longer descriptions. |

## Standard AD

Use `standard_ad` when you want concise descriptions that avoid interrupting dialogue or important audio. This is usually the right choice for videos with enough natural pauses, simple scenes, or workflows that need a separate audio description track.

```json theme={null}
{
  "generation_config": {
    "ad_type": "standard_ad",
    "auto_fit": true
  }
}
```

## Extended AD

Use `extended_ad` when the video has dense visual information, important on-screen context, or scenes that need more detail than natural pauses allow. Extended AD is useful for educational material, tutorials, government meetings, news, and other content where missing visual details can make the video hard to follow.

```json theme={null}
{
  "generation_config": {
    "ad_type": "extended_ad",
    "read_all_onscreen_text": true
  }
}
```

## Related Settings

| Option                          | Applies to                  | Description                                                                   |
| ------------------------------- | --------------------------- | ----------------------------------------------------------------------------- |
| `auto_fit`                      | Standard AD and Extended AD | Fits descriptions into detected no-speech zones when possible.                |
| `allow_descriptions_over_music` | Standard AD and Extended AD | Allows descriptions over detected music when no better timing is available.   |
| `read_all_onscreen_text`        | Extended AD                 | Forces the model to read on-screen text verbatim for supported content types. |