MPEG-2 doesn't support video larger than 1920x1152, so it's hard to compare on 4k video, let alone 8k. But according to https://www.researchgate.net/publication/321412719_Subjectiv... H.265 can achieve similar visual quality with 10% of the bit rate of MPEG-2 even on SD video (832*480). [Edit: not 720p]