A method and system for monitoring video assets provided by a multimedia content distribution network includes testing closed captions provided in output video signals. A video and audio portion of a video signal are acquired during a time period that a closed caption occurs. A first text string is extracted from a text portion of a video image, while a second text string is extracted from speech content in the audio portion. A degree of matching between the strings is evaluated based on a threshold to determine when a caption error occurs. Various operations may be performed when the caption error occurs, including logging caption error data and sending notifications of the caption error.