cslgAtom property
When enabled, file composition times will start at zero, composition times in the 'ctts' (composition time to sample) box for B-frames will be negative, and a 'cslg' (composition shift least greatest) box will be included per 14496-1 amendment 1. This improves compatibility with Apple players and tools.
Implementation
final Mp4CslgAtom? cslgAtom;