Try the follow code which resample every linked media in the open presentations.
Sub Embed() Dim l As Slide Dim s As Shape Dim oDoc As Presentation On Error Resume Next For Each oDoc In Application.Presentations For Each l In oDoc.Slides For Each s In l.Shapes With s.MediaFormat If .IsLinked And s.MediaType = ppMediaTypeMovie Then .Resample False, .SampleHeight, .SampleWidth, _ .VideoFrameRate, .AudioSamplingRate End If End With Next Next oDoc.Save Next End Sub
For your first tests "Do not use this code on your original presentations"
This code is provided "AS IS" without warranties, I've tested on my presentations and it work fine.