Add video content to the viewer

  duration = Inf,
  time_start = 0,
  asp_ratio = 16/9,
  local = TRUE



local file path or 'URL'


duration of the video


start time relative to the stimuli onset


aspect ratio; default is 16/9


used only when path is a 'URL': whether to download the video before generating the viewer; see 'Details'


The video path can be either local file path or a 'URL' from websites. When path is from the internet, there are two options: download the video before generating the viewer, or directly use the 'URL'.

If download happens before a viewer is generated (local=TRUE), then the video content is local. The viewer will be self-contained. However, the distribution will contain the video, and the archive size might be large.

If raw 'URL' is used (local=FALSE), then viewer is not self-contained as the video link might break anytime. The 'screenshot' and 'record' function might be limited if the 'URL' has different domain than yours. However, the distribution will not contain the video, hence smaller. This works in the scenarios when it is preferred not to share video files or they are licensed, or simply distribution is limited. Besides, this method is slightly faster than the local alternatives.