Encrypting the Video file in SD-CARD in react native

I was able to successfully encrypt and decrypt the videos using AES encryption. It worked good for smaller videos while for the bigger files it gave us the memory out/Overflow exception. Is there a better way to safe guard the video files where only my application can have the access to it. I am using this library "node-forge"

How are Video streaming apps like Netflix and Amazon prime are securing the videos locally, which are accessible only through their apps. If they are decrypting the whole file, how is the process so fast?

I was just wondering if we can just corrupt the file and de-corrupt while converting to base-64 ?

EDIT: This is a E-learning application where videos are accessed through SD Card securely. These Videos should be secured and can be played in only our app.

from Encrypting the Video file in SD-CARD in react native