ffmpeg-cli

name	ffmpeg-cli
description	Use FFmpeg to convert, process, and manipulate video and audio files from the terminal. Transcode formats, extract audio, create thumbnails, trim clips, and more.

FFmpeg

The universal multimedia framework. Convert, process, and stream video and audio.

• Official site: https://ffmpeg.org
• Docs: https://ffmpeg.org/documentation.html

Common Commands

Format Conversion

ffmpeg -i input.mp4 output.webm                    # Convert MP4 to WebM
ffmpeg -i input.mov output.mp4                      # Convert MOV to MP4
ffmpeg -i input.wav output.mp3                      # Convert WAV to MP3
ffmpeg -i input.mp4 -c:v libx264 -crf 23 output.mp4  # Re-encode with H.264

Extract Audio

ffmpeg -i video.mp4 -vn -acodec mp3 audio.mp3      # Extract audio as MP3
ffmpeg -i video.mp4 -vn -acodec pcm_s16le audio.wav # Extract as WAV
ffmpeg -i video.mp4 -vn -c:a copy audio.aac         # Extract without re-encoding

Trim and Cut

ffmpeg -i input.mp4 -ss 00:01:00 -to 00:02:00 -c copy clip.mp4  # Cut 1:00-2:00
ffmpeg -i input.mp4 -ss 30 -t 10 -c copy clip.mp4               # 10 seconds starting at 30s

Thumbnails and Screenshots

ffmpeg -i input.mp4 -ss 00:00:05 -frames:v 1 thumb.png          # Screenshot at 5s
ffmpeg -i input.mp4 -vf "fps=1/10" thumb_%04d.png               # One frame every 10s
ffmpeg -i input.mp4 -vf "thumbnail" -frames:v 1 best_thumb.png  # Best thumbnail

Resize and Scale

ffmpeg -i input.mp4 -vf "scale=1280:720" output.mp4             # Resize to 720p
ffmpeg -i input.mp4 -vf "scale=-1:480" output.mp4               # Scale height, keep ratio

GIF Creation

ffmpeg -i input.mp4 -ss 0 -t 5 -vf "fps=10,scale=320:-1" output.gif

Concatenation

# Create file list: file 'clip1.mp4'\nfile 'clip2.mp4'
ffmpeg -f concat -safe 0 -i filelist.txt -c copy output.mp4

Audio Processing

ffmpeg -i input.mp3 -af "volume=1.5" louder.mp3                 # Increase volume
ffmpeg -i input.mp3 -af "atempo=1.5" faster.mp3                 # Speed up audio
ffmpeg -i input.mp4 -an output_silent.mp4                       # Remove audio

Probe (inspect file)

ffprobe -v quiet -print_format json -show_format -show_streams input.mp4

Agent Best Practices

• Use -c copy when possible to avoid re-encoding (much faster)
• Use ffprobe to inspect files before processing
• Use -y flag to overwrite output without prompting
• Use -hide_banner to reduce noisy output
• CRF (Constant Rate Factor) controls quality: 18 = high, 23 = default, 28 = low
• Use -preset ultrafast for quick encodes, -preset slow for quality
• Pipe output to /dev/null and use -progress pipe:1 for parseable progress

Example Workflows

Convert video for web

ffmpeg -y -hide_banner -i input.mov -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k output.mp4

Get video duration

ffprobe -v quiet -show_entries format=duration -of csv=p=0 input.mp4