Method for switching audiovisual interfaces and circuit system

A circuit system, adapted to a sink device, comprising:

• a status and control data channel control module communicating with a corresponding one of multiple audio-visual sources via a status and control data channel and providing the corresponding audio-visual source for polling data, so as to allow the multiple audio-visual sources to determine whether or not multiple audio-visual interfaces of the sink device are in continuous operation;
• a fixed rate link (FRL) audio-visual packet detection module re-establishing an FRL by detecting signals, determining a transmission rate of the FRL, and determining FRL packets;
• wherein the circuit system performs a method for switching audio-visual interfaces, comprising:
• when multiple audio-visual interfaces of the sink device are connected with multiple audio-visual sources, the status and control data channel control module continuously responds to a status and control data channel communication request sent from a corresponding audio-visual source to the sink device;
• continuously issuing fixed rate link (FRL) signals with respect to the multiple audio-visual sources in response to responses sent by the status and control data channel control module;
• and
• when the sink device switches to one of the audio-visual interfaces, the FRL audio-visual packet detection module of the circuit system starts to detect the FRL signals sent by one of the audio-visual sources that corresponds to the audio-visual interface to be switched to, and establishes the fixed rate link with the audio-visual interface to be switched to, so that the sink device receives audio-visual data delivered from the audio-visual source connected with the audio-visual interface based on a rate information.