The working process of a digital TV set-top box is as follows: the high-frequency head receives high-frequency signals from a wired network, the channel is decoded through a QAM demodulator, and the transmission gate containing audio, video and other data information is separated from the carrier. The transmission stream generally contains multiple audio, video and some data information. Demultiplexer is used to distinguish different programs, extract the corresponding audio, video and data streams, send the MPEG - 2 decoder and the corresponding parsing software, and complete the restoration of digital information.