Uploading a lot of videos and storage

Just a general question here, hope someone can advise.

I am going to allow a whole load of vidoes to be uploaded onto my site ~ 1k.

I am already storing images and other uploads such as vidoes and other files in S3.

1. Just wondering how much do I need to consider encoding vidoes and anything else?
2. Should I store everything in s3?
3. Is it worth using something like cloudinary or anything else instead?

Thanks
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