Almost all mobile phones support a maximum resolution of 176X144 for video recording, cos this is the standerd resolution for MMS Videos, anything higher will not be standerd complient
Nokia N93 support recording at 640X480 with 1mbps bitrate, however if u chose to send that video as MMS, N93 will again convert it to 176X144, else it will not be a complient 3gp file & refuse to transmit through the network