FFmpeg Command Builder

Build FFmpeg commands visually — select an operation, fill in the inputs, and copy the ready-to-run command.

Presets:

Input File

File name or path

Start Time

End Time

Output File

Re-encode?

Flag Reference

Presets:

Input File

Width (px)

Use -1 to maintain aspect ratio

Height (px)

Use -1 to maintain aspect ratio

Video Codec

Output File

Flag Reference

Presets:

Input File

Output Format

Quality (CRF 0–51)

Lower = better quality / larger file

Output File

Flag Reference

Input File

Codec

CRF Quality (0–51)

18–23 = visually lossless; 28 = good quality; 35+ = lossy

Preset (speed vs compression)

Output File

Flag Reference

Input File

Audio Format

Bitrate

Output File

Flag Reference

Input Video

Subtitle File (.srt / .ass)

Subtitle Mode

Output File

Flag Reference

Input File

Speed Multiplier

0.25x = slow-mo; 2x = double speed; 4x = fast-forward

Change audio speed?

Output File

Flag Reference

About FFmpeg

FFmpeg is a free, open-source command-line tool for recording, converting, and streaming audio and video. It powers many popular video editing applications under the hood. Learning the command-line interface unlocks batch processing, scripting, and precise control over encoding parameters.

The CRF (Constant Rate Factor) value controls quality: lower numbers produce higher quality and larger files. For H.264, CRF 18 is near-lossless, 23 is the default (good balance), and 28+ is noticeably lossy. H.265 typically needs CRF values 4-6 higher than H.264 to match the same quality.

The encoding preset controls the trade-off between encoding speed and compression efficiency. "medium" is the default. "slow" and "veryslow" produce smaller files at the same quality but take longer. "ultrafast" is fastest but produces larger files.