1. A method comprising: receiving input indicating a location within a content stream, the content stream comprising in-band data; determining one or more portions of the in-band data in vicinity of the location within the content stream; determining at least two hash values from the one or more portions; determining one or more time values representing a period of time between when one hash value of the at least two hash values was determined and when the other hash value of the at least two hash values was determined; and storing location identification data comprising the at least two hash values and the one or more time values.