2 Replies
Matthew Bibby

Video is more complex than it appears... mp4 is a container, which simply defines how to store the audio and video streams. The video and audio streams are then decoded by codecs.

So you can have a .mp4 container (which is compatible with Storyline) that has data that was encoded with codecs that Storyline doesn't support. 

So you'll need to convert the video that isn't working. If you don't already have a preferred tool, Miro video converter is free and easy to use.