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#x264
1 articles
01
2026-08-13
·
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.