A video encoding method includes: during a first period, performing an encoding process upon a first block group of a current frame to generate a first block group bitstream; and during a second period, transmitting a second block group bitstream derived from encoding a second block group of the current frame, wherein the second period overlaps the first period. The encoding process includes: during a first time segment of the first period, performing a first in-loop filtering process upon a first group of pixels; and during a second time segment of the first period, performing a second in-loop filtering process upon a second group of pixels, wherein the second time segment overlaps the first time segment, and a non-zero pixel distance exists between a first edge pixel of the first group of pixels and a second edge pixel of the second group of pixels in a filter direction.