Question: Design a video streaming platform like Prime Video.
Requirements: Video upload, transcoding, streaming to millions of concurrent viewers, content recommendations.
Architecture: Upload Service (S3 for raw files), Transcoding Pipeline (convert to multiple resolutions: p, p, p, K). CDN (CloudFront) for delivery. Adaptive Bitrate Streaming adjusts quality based on user bandwidth.
Storage: Raw videos in S3. Metadata in DynamoDB. Transcoded segments in S3, served through CloudFront edge locations.
Scale: Millions of concurrent streams. Pre-warm CDN for new releases. DRM protection to prevent piracy. Recommendation engine uses viewing history + collaborative filtering.