plcmt 1 means Instream
Pre-, mid-, or post-roll inside video the viewer chose, with sound on at start or clear intent to watch.
When to send it
Send 1 when the ad plays before, during, or after video content the viewer asked to watch, and that video is the main thing on the screen. The definition adds tests the old In-Stream value never had: the player must start with sound on or the viewer must have shown clear intent to watch, and it must be the only player in view that can play audio. If the player later becomes floating or sticky, later ad calls should report the new player size. Full-episode CTV and live streams are 1.
Instream is the video inventory buyers pay the most for, and many line items accept only Video.plcmt 1. That makes misclassification costly both ways: a muted autoplay player sold as 1 gets audited and devalued, while honest instream inventory sent without plcmt can miss instream deals. It is most often confused with 2 (Accompanying Content) and with old Video.placement 1, which had no sound or intent test. Pair it with Video.startdelay to say where in the content the break sits.
Example
{
"imp": [
{
"video": {
"plcmt": 1
}
}
]
}Fields that carry it
Other values in plcmt subtypes (video)
| Value | Name |
|---|---|
2 | Accompanying Content |
3 | Interstitial |
4 | No Content/Standalone |
5 | Pause |
6 | Screensaver |
7 | Overlay |
8 | Squeezeback |
9 | In-scene |
The plcmt subtypes (video) list page explains the whole list and its common mistakes.