Method and apparatus for encoding, decoding, or displaying picture-in-picture

Abstract

Various embodiments provide example apparatus, method, and computer program product. An example apparatus includes: receiving or generating a first encoded bitstream comprising independently encoded subpictures; receiving or generating a second encoded bitstream comprising independently encoded subpictures; wherein resolution of subpictures in the second encoded bitstream is same or substantially same as resolution of corresponding subpictures in the first encoded bitstream; generating an encapsulated file with a first track and second track, the first track comprises the first encoded bitstream comprising the independently encoded subpicture, the second track comprises the second encoded bitstream comprising the independently encoded subpictures; and wherein generating the encapsulated file comprises including following information in the encapsulated file: a picture-in-picture relationship between the first track and second track; and data units independently encoded subpictures in the first encoded bitstream that are to be replaced by data units of the independently encoded subpictures of the second encoded bitstream.