The process of compressing video requires the calculation of a variety data that are used in the process of compression. The invention exploits some or all of these data for purposes of content detection. For example, these data may be leveraged for purposes of commercial detection. The luminance, motion vector field, residual values, quantizer, bit rate, etc. may all be used either directly or in combination, as signatures of content. A process for content detection may employ one or more features as indicators of the start and/or end of a sequence containing a particular type of content and other features as verifiers of the type of content bounded by these start/end indicators. The features may be combined and/or refined to produce higher-level feature data with good computational economy and content-classification utility.