Indeed, Amphetamine has a distinct molecular structure of C9H13N whereas Methamphetamine is C10H15N. The substance consumed in these videos is not Methamphetamine.
See:
- https://www.euda.europa.eu/publications/drug-profiles/amphetamine_en
- https://www.euda.europa.eu/publications/drug-profiles/methamphetamine_en
(still bad though, don't get me wrong)