4K Content!
Netflix uses the cartesian product of codec formats (F) and Resolutions (R) and stores these different combinations. Now based on the bandwidth the expected video is sent!
Optimized shot-based encodes
To improve our members’ video quality, we developed and deployed per-title encoding in 2015, followed by better mobile encodes for downloads a year later. Our next step was productizing a shot-based encoding framework, called Dynamic Optimizer
With Dynamic Optimizer, instead of making 3-minute chunks of 1 ep of stranger things, 4 sec chunks are made and clubbed together to match a scene. That way if buffering happens, it doesnt happen between a scene!
One more thing, if user is just clicking on different points in a timeline, they don’t send the next scenes and only sends what user asked for! This is called a sparse title/movie. If user is watching the entire movie without skipping, it sends next scenes for smooth experience. This is called a dense title.
CDN on drugs!
For faster delivery of content, we use CDN. Netflix put this CDN on drugs. It made a tie up with the ISP! They gave a server to the ISP which has all the movies. Now at peak hours of traffic, the data was already local! So ISP also saved a lot of traffic and users got to see the content without buffering!
Now you would say what about new movies? How are they updated at the ISP? These are updated early morning when there is no traffic!
Guess what? Youtube also doing this!
