A video processing method includes receiving a bitstream, and decoding, by a video decoder, the bitstream to generate a decoded frame. The decoded frame is a projection-based frame that has a 360-degree image/video content represented by triangular projection faces packed in a triangle-based projection layout. An omnidirectional image/video content of a viewing sphere is mapped onto the triangular projection faces via a triangle-based projection of the viewing sphere. An equator of the viewing sphere is not mapped along any side of each of the triangular projection faces.