1. A video encoding circuit comprising: a transform processor configured to: receive original data comprising video information, process the received original data by using at least one of first and second processing methods, and generate at least one of first and second transformed data, each of the first and second transformed data comprising coefficients, the coefficients having indexes respectively assigned according to a scan order; index determination logic configured to determine an index satisfying a determination condition from among the indexes respectively assigned to the coefficients, based on at least one of the first transformed data generated by the first processing method and the second transformed data generated by the second processing method; energy compaction determination logic configured to determine energy compaction of at least one of the first and second transformed data, based on the determined index; output selection logic configured to selectively output one of the first and second transformed data, based on the determined energy compaction; and an entropy encoder configured to encode data output from the output selection logic to generate encoded data.