Youtube automatically generates closed captions for videos. FindLectures.com crawls these, and allows you to search for a phrase within a video and start playback where the phrase occurs.

Machine-generated transcriptions include timestamps, but also many transcription errors. If we can obtain captions and a corrected transcript for a speech, these can be aligned using the words that do match. In the spots that differ, we can update the language with the corrected wording from the transcript.