TTrimpx

Interactive Tool

FFmpeg CRF Quality Calculator

CRF (Constant Rate Factor) controls video quality in FFmpeg and Shotcut MLT. Lower values = better quality but larger files. Use this calculator to find the sweet spot.

500 MB
CRF 23

Estimated Output Size

~500 MB

Normal quality — good for web delivery

Generated Command:

melt "input.mp4" -consumer avformat:"output.mp4" vcodec=libx264 crf=23

Click to copy

CRF Quality Scale — Quick Reference

CRF 0Lossless — massive file
CRF 18Visually lossless — editing masters
CRF 23Default — great quality for web (recommended)
CRF 28Smaller file, acceptable quality — social media
CRF 35+Small file, visible artifacts — streaming only

Format-Specific Recommendations

  • H.264 (MP4): CRF 23 is the sweet spot for most use cases
  • VP9 (WEBM): Add +3 to the CRF value (e.g., CRF 26 instead of 23)
  • H.265/HEVC: Subtract -3 from the CRF value for similar quality
FFmpeg Filters Guide: FFmpeg Filters Guide