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Partly tested: only ffmpeg -version was run (ffmpeg 9.0.2, Windows 11, 2026-10-31). The convert and transcode steps are untested and restated from the cited docs.

Summary

ffmpeg reads inputs (-i) and writes outputs. Prefer streamcopy (-c copy) when you only need a different container; transcode only when a filter or codec change is required [S1].

Agent access

• CLI: yes (ffmpeg, plus ffprobe in a full build). MCP connector: none connected. API: libav* libraries. GUI: optional front-ends, not needed.
• Best route: CLI.
• Permissions: local filesystem. Network URLs as -i need network. Overwrite needs -y [S1].

Steps

1. Version (tested 2026-10-31 on the test PC): ffmpeg -version printed ffmpeg version 9.0.2-full_build-www.gyan.dev Copyright (c) 2000-2026 the FFmpeg developers [F1][S2].
2. Convert container without re-encode (untested): ffmpeg -i input.mkv -map 0:1 -c copy output.mp4 [S1].
3. Transcode video, copy audio (untested): ffmpeg -i INPUT.mkv -map 0:v -map 0:a -c:v libx264 -c:a copy OUTPUT.mp4 [S1].
4. Do not overwrite by accident: default asks; scripts use -n to refuse existing outputs, or -y only when replacing is intended [S1].
5. Quiet logs in scripts: -hide_banner (and -loglevel error when you only want failures) [S1].

Traps

• Options apply to the next file; put all inputs first, then outputs [S1].
• Argument order matters for -ss/-t (input vs output) and for maps [S1].
• Without -c copy, audio/video/subtitles are transcoded with the muxer's default encoder [S1].
• Automatic stream selection picks one video (highest resolution), one audio (most channels), and may skip data/attachments unless -map is used [S1].
• Do not run GPU encodes (nvenc / CUDA) on a shared machine while another job is using the GPU.

What worked looks like

Version line starts with ffmpeg version 9.0.2-full_build-www.gyan.dev. A convert job (untested here) would exit 0 and write the named output.

Facts

• id: F1 claim: ffmpeg -version on the test PC on 2026-10-31 printed "ffmpeg version 9.0.2-full_build-www.gyan.dev Copyright (c) 2000-2026 the FFmpeg developers". confidence: high date: 2026-10-31 sources: [S2] license: CC0 1.0 checked_on: 2026-10-31
• id: F2 claim: ffmpeg -c copy copies packets without decoding or encoding (streamcopy). confidence: high date: 2026-10-31 sources: [S1] license: CC0 1.0 checked_on: 2026-10-31

@misc{iil_note_fd8n9tc1,
  author = {{iinventedlight}},
  title = {{ffmpeg: convert and inspect media from the command line}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-10-31},
  url = {https://iinventedlight.com/library/notes/ffmpeg-media-convert/},
  note = {Permanent ID iil:note:fd8n9tc1. License: CC0-1.0.},
}

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