A method for determining a preferred image resolution in a User Equipment, UE, supporting a mobile video call, the method comprising: receiving, from an opposing UE, a Session Description Protocol, SDP, offer message including a first maximum image resolution of the opposing UE and a first preferred image resolution of the opposing UE which is smaller than or equal to the first maximum image resolution; determining (520, 530, 540) whether the first preferred image resolution requested by the opposing UE is acceptable; and sending, to the opposing UE, a video transmission control information including a response message and starting the mobile video call according to the first preferred image resolution, when the first preferred image resolution is acceptable, and an SDP message including a second maximum image resolution and a new preferred image resolution as a new SDP offer message, when the first preferred image resolution is not acceptable; wherein determining whether the first preferred image resolution is acceptable comprises: (i) determining whether the first maximum image resolution can be accepted; (ii) if it is determined that the first maximum image resolution is acceptable, determining whether the first preferred image resolution is acceptable in combination with the first maximum image resolution; and (iii) if it is determined that the first preferred image resolution is acceptable in combination with the first maximum image resolution, determining whether a video encoder and a camera support the first preferred image resolution. receiving, from an opposing UE, a Session Description Protocol, SDP, offer message including a first maximum image resolution of the opposing UE and a first preferred image resolution of the opposing UE which is smaller than or equal to the first maximum image resolution; determining (520, 530, 540) whether the first preferred image resolution requested by the opposing UE is acceptable; and sending, to the opposing UE, a video transmission control information including a response message and starting the mobile video call according to the first preferred image resolution, when the first preferred image resolution is acceptable, and an SDP message including a second maximum image resolution and a new preferred image resolution as a new SDP offer message, when the first preferred image resolution is not acceptable; wherein determining whether the first preferred image resolution is acceptable comprises: (i) determining whether the first maximum image resolution can be accepted; (ii) if it is determined that the first maximum image resolution is acceptable, determining whether the first preferred image resolution is acceptable in combination with the first maximum image resolution; and (iii) if it is determined that the first preferred image resolution is acceptable in combination with the first maximum image resolution, determining whether a video encoder and a camera support the first preferred image resolution. (i) determining whether the first maximum image resolution can be accepted; (ii) if it is determined that the first maximum image resolution is acceptable, determining whether the first preferred image resolution is acceptable in combination with the first maximum image resolution; and (iii) if it is determined that the first preferred image resolution is acceptable in combination with the first maximum image resolution, determining whether a video encoder and a camera support the first preferred image resolution.