Communication apparatus and control method thereof

A communication apparatus comprising:

• a data communication unit which performs half-duplex communication of video frame data with an external device on a video frame-by-video frame basis;
• a control signal communication unit which communicates control signals with the external device asynchronously with respect to communication by the data communication unit;
• a switching unit which switches a transmission direction in which the data communication unit transmits the video frame data;
• a first control unit which, when the transmission direction is to be switched while the data communication unit is sending the video frame data, controls the control signal communication unit to send a start command for instructing a start of a transmission direction switch, as well as controls the switching unit to calculate an amount of video frame data that can be sent before the start command reaches the external device and is interpreted and switches the transmission direction in response to completion of the sending of video frame data of an amount greater than or equal to the calculated amount;
• and
• a second control unit which, when the control signal communication unit has received the start command while the data communication unit is receiving video frame data, controls the switching unit to switch the transmission direction in response to completion of the reception of the video frame data by the data communication unit.

A control method for a communication apparatus, the communication apparatus including a data communication unit which performs half-duplex communication of video frame data with an external device on a video frame-by-video frame basis, a control signal communication unit which communicates control signals with the external device asynchronously with respect to communication by the data communication unit, and a switching unit which switches a transmission direction in which the data communication unit transmits the video frame data, the control method comprising:

• controlling, when the transmission direction is to be switched while the data communication unit is sending the video frame data, the control signal communication unit to send a start command for instructing a start of a transmission direction switch, as well as controlling the switching unit to calculate an amount of video frame data that can be sent in time until the start command reaches the external device and is interpreted and switch the transmission direction in response to completion of the sending of video frame data of an amount greater than or equal to the calculated amount;
• and
• controlling, when the control signal communication unit has received the start command while the data communication unit is receiving video frame data, the switching unit to switch the transmission direction in response to completion of the reception of the video frame data by the data communication unit.