Yes, we know that. Video playback has physical constraints; a file format where image elements are sampled at irregular time intervals is obviously possible and

Yes, we know that. Video playback has physical constraints; a file format where image elements are sampled at irregular time intervals is obviously possible and useful for very "scientific" purposes like measuring when images are acquired and interpolating the raw data, but not reasonable for playing back on a screen with good compression and easy decompression.