ffmpeg

# ffmpeg ## Use when - Extract audio from a video file. - Transcode an MP4 video to WebM. ## Don't use when - A higher-level video-editing skill or tool is already in use for complex edits. - The task is purely file transfer or metadata inspection (no transcoding needed). ## Outputs - Output files should be written to `artifacts/` when possible (e.g., `artifacts/output.webm`). ## Templates or Examples - Use the command blocks below as templates, swapping inputs/outputs and codecs as needed. ## Requirements - Prefer safe defaults and explicit codecs. - Keep commands minimal and reproducible. - Use ASCII-only output unless file already uses Unicode. ## Commands ### Extract audio (MP4 → MP3) ``` ffmpeg -y -i input.mp4 -vn -c:a libmp3lame -q:a 2 output.mp3 ``` ### Extract audio (MP4 → WAV, lossless) ``` ffmpeg -y -i input.mp4 -vn -c:a pcm_s16le -ar 44100 -ac 2 output.wav ``` ### Transcode MP4 → WebM (VP9 + Opus) ``` ffmpeg -y -i input.mp4 -c:v libvpx-vp9 -crf 32 -b:v 0 -row-mt 1 -c:a libopus -b:a 128k output.webm ``` ### Transcode MP4 → WebM (VP8 + Vorbis) ``` ffmpeg -y -i input.mp4 -c:v libvpx -crf 10 -b:v 1M -c:a libvorbis -b:a 128k output.webm ``` ## Notes - `-y` overwrites output files. Remove if you want interactive prompts. - Lower `-crf` means higher quality (and larger files). - If audio-only extraction is desired, use `-vn` to drop video.