The InChI Trust has four short videos about the use and importance of using InChI (International Chemical Identifiers) to represent chemical structures. InChIs convey more information than SMILES, including structural changes such as tautomerization(1), which can be useful in structural searching. InChI identifiers are produced by a computer program from a structural drawing, and vice versa. An InChI generator is available from RSC.
Heller, S, McNaught, A, Stein, S, Tchekhovskoi, D, Pletnev, I: InChI – the worldwide chemical structure identifier standard. J Cheminformatics, 2013, 5:7. doi:10.1186/1758-2946-5-7