Obs Media Source Delay

Yes, this can be done with OBS Raw (OBS -> Raw) and a GetMediaInputStatus request. Paste the code below into the Raw subaction and replace the inputName with the name of your media source. This request will populate a %obsRaw.mediaDuration% variable that gives the media duration in milliseconds. You can then use that variable within the Delay subaction.

Note: For the variable to populate, the media source needs to be visible. Use a Set Source Visibility State subaction to make it visible, add a delay of 100ms and then use the Raw subaction. (Example: see here)

{
  "requestType": "GetMediaInputStatus",
  "requestData": {
    "inputName": "Your Media Source"
  }
}