  Automatic video description requires the generation of natural language
statements about the actions, events, and objects in the video. An important
human trait, when we describe a video, is that we are able to do this with
variable levels of detail. Different from this, existing approaches for
automatic video descriptions are mostly focused on single sentence generation
at a fixed level of detail. Instead, here we address video description of
manipulation actions where different levels of detail are required for being
able to convey information about the hierarchical structure of these actions
relevant also for modern approaches of robot learning. We propose one hybrid
statistical and one end-to-end framework to address this problem. The hybrid
method needs much less data for training, because it models statistically
uncertainties within the video clips, while in the end-to-end method, which is
more data-heavy, we are directly connecting the visual encoder to the language
decoder without any intermediate (statistical) processing step. Both frameworks
use LSTM stacks to allow for different levels of description granularity and
videos can be described by simple single-sentences or complex multiple-sentence
descriptions. In addition, quantitative results demonstrate that these methods
produce more realistic descriptions than other competing approaches.
