Wireless communication system, transmitter, receiver, and communication terminal

When switching a communication method from one to another, the present invention synchronizes, in a receiver, an I picture of video data transmitted by a communication method before the switchover and video data transmitted by a communication method after the switchover with each other and then switches the communication method immediately before the I picture. Synchronous data is generated by a transmitter, and the synchronous data is referenced by the receiver as the receiver performs synchronization. The video can be prevented from becoming discontinuous at a time when the communication method is switched from one to another. 在通信方式的切换时，在接收装置中，在使利用切换前的通信方式发送来的视频数据的I图像与利用切换后的通信方式发送来的视频数据彼此同步之后，在I图像之前进行切换。利用发送装置生成同步数据，利用接收装置参照同步数据而进行同步。在切换通信方式时，能够防止视频变得不连续。