A video authoring system has an authoring computing device that generates a visual synchronization layout, via a graphical user interface without user-based inputting of computer executable code, for a video with a time duration and for content to be added to the video at one or more time-based positions within the video. The video authoring system also has a processor, in operable communication with the authoring computing device, that sends data associated with the visual synchronization layout to a remote server that automatically generates a manifest based on the data associated with the visual synchronization layout. The manifest is computer executable code that is executed by a media player at a computing device so that the media player plays the video in synchronization with the content.