Start delay modes value -1 means Generic Mid-Roll

Generic mid-roll: the ad plays during the content at an offset the seller does not state.

List: Start Delay ModesValue -1

When to send it

Send -1 when the ad will play during the content but the exact time is not known at request time. That is normal for dynamic ad insertion in live streams, server-side stitched CTV breaks, and podcast mid-rolls.

Buyers price -1 as mid-roll, which on long-form content usually means an engaged viewer, but they lose the depth information a positive offset carries, so a seller that knows the break time should send it instead. It is confused with -2 (post-roll) and with positive values: -1 names a position, not a number of seconds.

Example

{
  "imp": [
    {
      "audio": {
        "startdelay": -1
      }
    }
  ]
}

Fields that carry it

Other values in start delay modes

Value	Name
`>0`	Mid-Roll (the value is the start delay in seconds)
`0`	Pre-Roll
`-2`	Generic Post-Roll

The start delay modes list page explains the whole list and its common mistakes.