FFmpeg Toolkit

Transcode

# Convert to MP4 (H.264 + AAC)
ffmpeg -i input.mov -c:v libx264 -preset medium -crf 23 \
       -c:a aac -b:a 128k output.mp4

# Convert to WebM (VP9 + Opus)
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 30 -b:v 0 \
       -c:a libopus -b:a 128k output.webm

Resize

# Specific dimensions
ffmpeg -i input.mp4 -vf "scale=1920:1080" output.mp4