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.

{
  "generation_config": {
    "ad_type": "standard_ad",
    "auto_fit": true
  }
}

Set standard_ad_min_cue_length to control the shortest silent gap a description may be placed in, in seconds. Gaps shorter than this are skipped instead of squeezing text in, so raise it for fewer, longer, more natural descriptions (useful for broadcast-style guidelines). The default is 0.75, the typical range is 0.75–5, and it only applies when auto_fit is on.

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.

{
  "generation_config": {
    "ad_type": "extended_ad",
    "read_all_onscreen_text": true
  }
}

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.
`standard_ad_min_cue_length`	Standard AD	Minimum silent-gap length, in seconds, where a description may be placed. Gaps shorter than this are skipped instead of squeezing text in. Default `0.75`; typical range `0.75`–`5`. Only applies when `auto_fit` is on.
`read_all_onscreen_text`	Extended AD	Forces the model to read on-screen text verbatim for supported content types.

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Standard AD vs Extended AD