Tasks usually have specific outcomes which are doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided in some way. For example:
A writing task involving filling doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided in a paragraph from a choice of phrases may be a half-way house on the road to writing a paragraph without guidance and it will have a right/wrong doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided.  Either the learners make the right choices, or they don't.
A task to write a 300-word essay on a subject of the learner's choosing is almost completely doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided but it will still have a measurable outcome (although it may be quite difficult to identify success or failure).
Activities do not usually have doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided outcomes because it is the doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided of doing the activity which is more important.  It is the doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided of the task which is important, not the ideas which come from it.
Getting students to tell each other what characters in a video clip they find the most and least attractive is certainly valuable doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided practice and also requires them to understand and provide doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided.  The process is what is important here because we cannot (and don't need to) doinggapslanguagemeasurablemeasureoutcomeprocessreasoningspecificunguided the outcomes in any useful way.