We propose a super-resolution method to convert spatial resolution from 2K to 8K to utilize existing 2K HDTV video for 8K UHDTV broadcasting. The proposed method uses image registration for wavelet multi-scale bands of 2K video frames considering future hardware implementation to real-time processing. This image registration consists of alignment and assignment procedures. The wavelet multi-scale bands are extracted using wavelet decomposition of 2K video frames. The alignment is processed from 2K video frames to its wavelet low-frequency bands. By using the alignment result, the assignment is processed from its wavelet high-frequency bands to super-resolved high-frequency bands. After these alignment and assignment procedures, super-resolved 8K video frames are reconstructed using wavelet reconstruction with 2K video frames and their super-resolved high-frequency bands generated in the assignment procedure. Experiments showed that the method provides objectively better PSNR and SSIM measurements and subjectively better appearance than conventional super-resolution methods.