Many thank @ptrblck
After your solution my Input size change to[2304, 20, 64]  after though RNN layer my output is the same size. So I try to reshape back to [20, 64, 48, 48] because my Network is CNN > RNN > CNN.
But somehow after thought RNN layer. some data in tensor have changed.
While I’m trying take the output back in CNN I got this error
TypeError: conv2d(): argument 'input' (position 1) must be Tensor, not tuple

Do you have any idea about this problem?