AWS bucket vs cloudfront for mp4 streaming

If I understand correctly, AWS will charge you for the amount of data leaving the bucket. If a lot of people begin downloading the file, your bill could go up more than you planned for. Something to be cautious about. On the other hand, if you switch to letting cloudfront serve the file, it won't be leaving your bucket as often, possibly saving you money. But it all depends on how much traffic you can handle.

1. Security - Making the bucket public will not allow you to track who access what objects in the bucket and per security guidelines you should always follow the security best practices
2. Cost - Content served directly from S3 is charged at this time of writing $0.0004 per 1000 GET's requests, plus $0.09 per GB for the first 10 TB and you will have per month a free allowance of 100 GB
3. Scalability - Amazon S3 can perform 5,500 GET/HEAD requests per second per partitioned prefix , once that limit is reached the requests will start receiving 503 response errors. Further information at https://docs.aws.amazon.com/AmazonS3/latest/userguide/optimizing-performance.html

Fronting the S3 Bucket with a CloudFront distribution endpoint will allow you to:

• Filter who can access the bucket
• Stop direct access to the bucket
• Cache content closer to the edge, reducing the number of S3 requests
• Reduce costs ($0.085 for the first 10 TB with a monthly free allowance of 1 TB)

For further information on how to restrict access to S3 Buckets with CloudFront, please see https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/private-content-restricting-access-to-s3.html