mediaproc

name	mediaproc
description	Process media files (video, audio, images) via a locked-down SSH container with ffmpeg, sox, and imagemagick
homepage	https://github.com/psyb0t/docker-mediaproc
user-invocable	true
metadata	{"openclaw":{"emoji":"🎬","primaryEnv":"MEDIAPROC_HOST","always":true}}

mediaproc

Setup Required

This skill requires MEDIAPROC_HOST and MEDIAPROC_PORT environment variables pointing to a running mediaproc instance.

Configure OpenClaw (~/.openclaw/openclaw.json):

{
  "skills": {
    "entries": {
      "mediaproc": {
        "env": {
          "MEDIAPROC_HOST": "localhost",
          "MEDIAPROC_PORT": "2222"
        }
      }
    }
  }
}

Or set the environment variables directly:

export MEDIAPROC_HOST=localhost
export MEDIAPROC_PORT=2222

---

Locked-down media processing over SSH. Uses a Python wrapper that whitelists commands - no shell access, no injection, no bullshit.

First Connection

Before running any commands, you must accept the host key so it gets added to known_hosts. Run a simple ls and accept the fingerprint:

ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ls"

If this is the first time connecting, SSH will prompt to verify the host key. Type yes to accept. This only needs to happen once per host. If you skip this step, all subsequent SSH commands will fail with a host key verification error.

How It Works

All commands are executed via SSH against the mediaproc container. The container forces every connection through a Python wrapper that only allows whitelisted commands. All file paths are locked to /work inside the container.

SSH command format:

ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "<command> [args]"

Media Tools

Command	Binary	Description
ffmpeg	/usr/bin/ffmpeg	Video/audio encoding, transcoding, filtering
ffprobe	/usr/bin/ffprobe	Media file analysis
sox	/usr/bin/sox	Audio processing
soxi	/usr/bin/soxi	Audio file info
convert	/usr/bin/convert	Image conversion/manipulation (ImageMagick)
identify	/usr/bin/identify	Image file info (ImageMagick)
magick	/usr/bin/magick	ImageMagick CLI

File Operations

All paths are relative to /work. Traversal attempts are blocked. Absolute paths get remapped under /work.

Command	Description	Example
ls	List /work or a subdirectory (ls -alph style, use --json for JSON)	ls or ls --json subdir
put	Upload file from stdin	put video.mp4 (pipe file via stdin)
get	Download file to stdout	get output.mp4 (redirect stdout to file)
rm	Delete a file (not directories)	rm old.mp4
mkdir	Create directory (recursive)	mkdir project1
rmdir	Remove empty directory	rmdir project1
rrmdir	Remove directory and everything in it recursively	rrmdir project1

Usage Examples

Upload and process a file

# Upload
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "put input.mp4" < input.mp4

# Transcode
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ffmpeg -i /work/input.mp4 -c:v libx264 /work/output.mp4"

# Download result
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "get output.mp4" > output.mp4

# Clean up
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "rm input.mp4"
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "rm output.mp4"

Video operations

# Get video info as JSON
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ffprobe -v quiet -print_format json -show_format -show_streams /work/video.mp4"

# Apply frei0r glow effect
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ffmpeg -i /work/in.mp4 -vf frei0r=glow:0.5 /work/out.mp4"

# Extract audio from video
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ffmpeg -i /work/video.mp4 -vn -acodec libmp3lame /work/audio.mp3"

# Create thumbnail from video
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ffmpeg -i /work/video.mp4 -ss 00:00:05 -vframes 1 /work/thumb.jpg"

Audio operations

# Convert audio format
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "sox /work/input.wav /work/output.mp3"

# Get audio info
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "soxi /work/audio.wav"

# Normalize audio
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "sox /work/input.wav /work/output.wav norm"

Image operations

# Resize image
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "convert /work/input.png -resize 50% /work/output.png"

# Create thumbnail
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "convert /work/input.jpg -thumbnail 200x200 /work/thumb.jpg"

# Get image info
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "identify /work/image.png"

File management

# List files (ls -alph style, no . and ..)
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ls"
# drwxrwxr-x   2 mediaproc mediaproc     4096 Jan 25 14:30 project1/
# -rw-rw-r--   1 mediaproc mediaproc  1048576 Jan 25 14:32 video.mp4

# List files as JSON (use --json flag)
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ls --json"
# [{"name": "video.mp4", "size": 1048576, "modified": 1706140800, "isDir": false, "mode": "rw-rw-r--", "owner": "mediaproc", "group": "mediaproc", "links": 1}, ...]

# List subdirectory
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "ls project1"

# Create subdirectory
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "mkdir project1"

# Remove directory recursively
ssh -p $MEDIAPROC_PORT mediaproc@$MEDIAPROC_HOST "rrmdir project1"

Available 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.

Security Notes

• No shell access - all commands go through a Python wrapper
• Whitelist only - unlisted commands are rejected
• No injection - &&, ;, |, $() are treated as literal arguments (no shell involved)
• SSH key auth only - no passwords
• All forwarding disabled
• All file paths locked to /work