A method is disclosed in which first payload data included in a first file container and second payload data included in a second file container are determined. The first payload data is decoded to determine first un-encoded data representing first content, and the second payload data is decoded to determine second un-encoded data representing second content. At least one difference is determined between the first un-encoded data and the second un-encoded data, and third un-encoded data corresponding to the at least one difference is determined. The third un-encoded data is encoded to generate third payload data representing third content, and a third file container is generated that includes the third payload data.