--- slug: "mediaproc-x-7" source_type: "clawhub" source_url: "https://clawhub.ai/skills/mediaproc" repo: "" source_file: "description" --- --- name: mediaproc description: Process media files (video, audio, images) via a locked-down SSH container with ffmpeg, sox, and imagemagick. Use when the user wants to transcode video, process audio, manipulate images, or work with media files. compatibility: Requires ssh and a running mediaproc instance. MEDIAPROC_HOST and MEDIAPROC_PORT env vars must be set. metadata: author: psyb0t homepage: https://github.com/psyb0t/docker-mediaproc --- # mediaproc Locked-down media processing over SSH. Built on [lockbox](https://github.com/psyb0t/docker-lockbox) — no shell access, no injection, no bullshit. For installation and deployment, see [references/setup.md](references/setup.md). ## Security model mediaproc is **not** a general-purpose shell, and `scripts/mediaproc.sh` is **not** arbitrary remote code execution even though it forwards a free-form-looking command string. The instance runs inside a [lockbox](https://github.com/psyb0t/docker-lockbox)- hardened container, and this skill only ever talks to an instance you (or your operator) already run and trust: - **Key-auth only** — SSH accepts public-key auth only (no passwords), connecting as a restricted user. There is no interactive shell and no PTY. - **Server-side enforced allow-list, not documentation** — `scripts/mediaproc.sh` passes its argument through to the SSH channel as-is, but the *remote* lockbox dispatcher is what decides what runs, and it only ever executes the fixed set documented below: `ffmpeg`, `ffprobe`, `sox`, `soxi`, `convert`, `identify`, `magick`, plus lockbox's built-in, scoped file operations. This is an enforced allow-list on the server, not a client-side convention — the wrapper cannot be used to run anything outside that set. Any other command name is refused before execution; the remote never spawns a shell, so there is no shell-injection surface and no way to chain (`;`, `|`, `&&`, backticks, etc.) into a second command. - **Work-dir confined** — every path resolves under the instance work directory (`/work`); traversal is blocked. The sandbox cannot read or write your host filesystem. - **Consumer-only** — this skill moves files to/from a running instance and runs the whitelisted media tools on them. It never provisions, escalates, or installs anything on your machine (server setup is a separate, operator-side step — see setup.md). - **You must still trust the configured host** — `MEDIAPROC_HOST`/`MEDIAPROC_PORT` point at a specific instance. The allow-list constrains *what* runs, not *where*; if `MEDIAPROC_HOST` is pointed at an instance you don't control, that operator still sees every file you `put`/`get` and every command you send. Only point this skill at a mediaproc instance you or a trusted operator run. ## SSH Wrapper Use `scripts/mediaproc.sh` for all commands. It handles host, port, and host key acceptance via `MEDIAPROC_HOST` and `MEDIAPROC_PORT` env vars. The `` argument looks free-form but is not arbitrary execution: the wrapper does no shell evaluation of it — it passes the whole string as a single argument over the SSH channel — and it is the *remote* lockbox dispatcher that enforces the allow-list from the Security model above, server-side, on every invocation. There is no local or remote shell in the loop, so there's no injection/chaining surface (`;`, `|`, `&&`, backticks, etc. are inert; the dispatcher just refuses anything that isn't the fixed command name it expects). ```bash scripts/mediaproc.sh [args] scripts/mediaproc.sh < input_file scripts/mediaproc.sh > output_file ``` ## Media Tools | Command | Description | | ---------- | -------------------------------------------- | | `ffmpeg` | Video/audio encoding, transcoding, filtering | | `ffprobe` | Media file analysis | | `sox` | Audio processing | | `soxi` | Audio file info | | `convert` | Image conversion/manipulation (ImageMagick) | | `identify` | Image file info (ImageMagick) | | `magick` | ImageMagick CLI | ## Upload, Process, Download ```bash # Upload scripts/mediaproc.sh "put input.mp4" < input.mp4 # Transcode scripts/mediaproc.sh "ffmpeg -i /work/input.mp4 -c:v libx264 /work/output.mp4" # Download result scripts/mediaproc.sh "get output.mp4" > output.mp4 # Clean up scripts/mediaproc.sh "remove-file input.mp4" scripts/mediaproc.sh "remove-file output.mp4" ``` ## Video Operations ```bash # Get video info as JSON scripts/mediaproc.sh "ffprobe -v quiet -print_format json -show_format -show_streams /work/video.mp4" # Apply frei0r glow effect scripts/mediaproc.sh "ffmpeg -i /work/in.mp4 -vf frei0r=glow:0.5 /work/out.mp4" # Extract audio from video scripts/mediaproc.sh "ffmpeg -i /work/video.mp4 -vn -acodec libmp3lame /work/audio.mp3" # Create thumbnail from video scripts/mediaproc.sh "ffmpeg -i /work/video.mp4 -ss 00:00:05 -vframes 1 /work/thumb.jpg" ``` ## Audio Operations ```bash # Convert audio format scripts/mediaproc.sh "sox /work/input.wav /work/output.mp3" # Get audio info scripts/mediaproc.sh "soxi /work/audio.wav" # Normalize audio scripts/mediaproc.sh "sox /work/input.wav /work/output.wav norm" ``` ## Image Operations ```bash # Resize image scripts/mediaproc.sh "convert /work/input.png -resize 50% /work/output.png" # Create thumbnail scripts/mediaproc.sh "convert /work/input.jpg -thumbnail 200x200 /work/thumb.jpg" # Get image info scripts/mediaproc.sh "identify /work/image.png" ``` ## File Operations All paths relative to the work directory. Traversal blocked. **Destructive.** `remove-file`, `remove-dir`, and `remove-dir-recursive` permanently delete data in the remote work directory — there is no trash/undo. `remove-dir-recursive` deletes an entire subtree in one call and is especially dangerous. Only run these after explicit user confirmation of the exact path. | Command | Description | | ---------------------- | ---------------------------------- | | `put ` | Upload file from stdin | | `get ` | Download file to stdout | | `list-files [--json]` | List directory | | `remove-file ` | Delete a file | | `create-dir ` | Create directory | | `remove-dir ` | Remove empty directory | | `remove-dir-recursive ` | Remove directory recursively | | `move-file `| Move or rename | | `copy-file `| Copy a file | | `file-info ` | Get file metadata as JSON | | `file-exists ` | Check if file exists (true/false) | | `file-hash ` | Get SHA256 hash | | `disk-usage [path]` | Get bytes used | | `search-files ` | Glob search | | `append-file ` | Append stdin to a file | ```bash # List files scripts/mediaproc.sh "list-files" # List as JSON (size, modified, isDir, permissions) scripts/mediaproc.sh "list-files --json" # List subdirectory scripts/mediaproc.sh "list-files project1" # File operations scripts/mediaproc.sh "create-dir project1" scripts/mediaproc.sh "move-file old.mp4 new.mp4" scripts/mediaproc.sh "copy-file input.mp4 backup.mp4" scripts/mediaproc.sh "file-info video.mp4" scripts/mediaproc.sh "file-exists video.mp4" scripts/mediaproc.sh "file-hash video.mp4" scripts/mediaproc.sh "search-files '*.mp4'" scripts/mediaproc.sh "disk-usage" scripts/mediaproc.sh "remove-dir-recursive project1" ``` ## Plugins - **frei0r** — Video effect plugins (used via `-vf frei0r=...`) - **LADSPA** — Audio effect plugins: SWH, TAP, CMT (used via `-af ladspa=...`) - **LV2** — Audio plugins (used via `-af lv2=...`) ## Fonts 2200+ fonts included covering emoji, CJK, Arabic, Thai, Indic, monospace, and more. Custom fonts can be mounted to `/usr/share/fonts/custom`.