Anne Aaron [pictured], Manager, Video Algorithms, and David Ronca, Director, Encoding Technology, explain in a post to Netflix Techblog how Netflix prepares its video content and "encode them to the best video streams possible for a given member’s viewing device and bandwidth capabilities" which turns out to be a bigger challenge than what most people think.
- How does Netflix Optimize Video? - here
- Sandvine: Streaming Video is 70% (Netflix 37%) of NA Fixed Traffic" - here.
"..At Netflix we stream to a heterogeneous set of viewing devices. This requires a number of codec profiles: VC1, H.264/AVC Baseline, H.264/AVC Main and HEVC. We also support varying bandwidth scenarios for our members, all the way from sub-0.5 Mbps cellular to 100+ Mbps high-speed Internet. To deliver the best experience, we generate multiple quality representations at different bitrates (ranging from 100 kbps to 16 Mbps) and the Netflix client adaptively selects the optimal stream given the instantaneous bandwidth"
See "High Quality Video Encoding at Scale" - here.