The invention discloses a set-top box. The set-top box comprises a signal transceiver, a controller, a converter, a resource scheduling processor and a memory, wherein the signal transceiver is used for completing the interaction of information and data; the controller is used for analyzing a received transcoding request, determining a transcoding scheme, and triggering the converter and the resource scheduling processor; the converter is used for obtaining the data of media to be transcoded, transcoding the data of the media to be transcoded according to the determined transcoding scheme, and transmitting the transcoded data of the media to the memory; the resource scheduling processor is used for downloading the data of the media to be transcoded and transmitting the downloaded data of the media to be transcoded to the memory according to the triggering of the controller, and obtaining and uploading the transcoded data of the media; the memory is used for storing the data of the media to be transcoded and the transcoded data of the media. Besides, the invention further discloses a method and system for realizing the data transcoding of the media based on the set-top box, through the use of the method and system disclosed by the invention, the data of the media with various high video coding standards can be played by low-performance media equipment, so that the family cost is minimized, and the resource utilization is maximized.