#rate-control
2 articles
01
·Media in Production·★ MEMBER·7 min read
How to Read Encoder Settings — What CRF, Presets, and 2-Pass Actually Change
The flags in an ffmpeg command — -crf 23, -preset slow, -pass 2 — each answer a different question: what to hold constant (CRF), how hard to search (preset), and whether to read the whole video first (2-pass). We derive why each knob works from the quantization-step formula and rate-distortion optimization, then land on copy-paste-ready commands and the mistakes that bite in production.
02
·Video Codecs·★ MEMBER·8 min read
Video Compression from Scratch — Motion Compensation and the GOP
Compressing thirty separate photographs a second gets nowhere near today's delivery bitrates. Why frame differencing breaks, what a motion vector actually carries, I/P/B frames and the GOP, and what CBR, VBR and CRF each hold constant — ending at the keyframe interval a delivery engineer has to choose.