Transmitting audio and video signals, can include: detecting if the state of a video control signal has changed, where a video signal includes the video control signal and a video data signal; generating, if the state of the video control signal has not changed, a first serial data packet based on the video signal and an audio signal; generating, if the state of the video control signal has changed, a second serial data packet based on the video signal and the audio signal; transmitting over a serial link, an encoded data frame formed by encoding the first and second serial data packets in a predetermined encoding manner; decoding and de-serializing the encoded data frame to restore the video signal and the audio signal; and outputting the video signal to a video display circuit, and outputting the audio signal to an audio processor respectively.