The increasing quantity of TV material requires methods to help users navigate such data streams. Automatically associating a short textual description with each program in a stream, is a first stage to navigating or structuring tasks. Speech contained in TV broadcasts--accessible by means of automatic speech recognition systems in the absence of closed caption--is a highly valuable semantic clue that might be used to link existing textual description such as program guides, with video segments corresponding to program. However, high word error rates are to be expected on some programs, likely to jeopardize the usefulness of transcripts. The goal of this article is to determine to what extent automatic transcripts of TV streams, for various types of programs, can be used for structuring or navigating tasks. To this end, word-based and phonetic-based automatic association between video segments and program descriptions is used as a case study. We show that descriptions from a program guide can be associated with video segments with an accuracy of up to 65% and provide a valuable description to validate existing program labels. Such associations constitute a first stage for structuring task as they enable video segment textual characterization.