In 2010, video encoding was an art. You tweaked settings until the file looked "good enough" on your specific monitor.
Adaptive Bitrate (ABR) streaming only works if your ladder matches real-world network conditions. According to the 2025 State of Internet Connectivity Report , the average global fixed broadband speed is 85 Mbps, but the median mobile speed is only 12 Mbps—and 30% of users drop to 3G speeds (2-4 Mbps) for at least 10% of their session.
In 2025, that approach is a liability.
Developed by Netflix in collaboration with the University of Southern California, VMAF is the gold standard in modern encoding. Unlike older metrics, VMAF combines several human vision models—including visual information fidelity (VIF) and detail loss metric (DLM)—into a single score.
High Dynamic Range (HDR) is where guesswork kills quality. You cannot use SDR numbers. In 2010, video encoding was an art
Use --hdr10-opt and --colour-primaries bt2020 . Without these flags, your HDR is just bright SDR.
The core philosophy is simple:
"Slow" takes 3x longer than "Medium" but only saves 18% bitrate. "Veryslow" is a waste (0.2 Mbps gain for 3x longer encode). The optimal number is "Slow" for VOD, "Medium" for live. "Veryfast" should only be used for live event previews. Eliminate guesswork: encode all non-live assets with preset=slow .
Use a hybrid ladder. Serve H.264 to legacy devices (smart TVs from 2015), HEVC to mobile and new browsers, and AV1 only to high-end Android TV and YouTube-scale publishers. According to the 2025 State of Internet Connectivity
This isn’t theory. This is the math behind flawless playback.