possessive pronoun or possessive adjective

Hello,

In a video of grammar explanation https://www.youtube.com/watch?v=oSffnJjuGlQ I saw that the word 'my' is defined as a possessive "pronoun",
time : 8' 52'' and 11' 43".
I believed that 'my' was an adjective and 'mine' a pronoun. In this video, 'my' and 'mine' are both defined as pronouns.
Is it a mistake of the video or can the word 'my' be also defined as "pronoun"?

Thank you.