User Guide

Starting Transmission 

./transmission

This launches the GTK graph editor. The launcher sets GDK_BACKEND=x11 and TRANSMISSION_ROOT, and suppresses the auto-spawned live server (run transmission-live.js separately if needed).

To start the live HTTP/MCP server alongside:

node scripts/transmission-live.js

Graph editing

The graph editor shows nodes as boxes and connections as directed edges.

Action How
Add a node Right-click on the canvas → select plugin
Move a node Drag its title bar
Connect two nodes Drag from an output port to an input port
Remove a connection Right-click the connection line
Remove a node Right-click the node → Remove
Open plugin editor Double-click the node

Port colours indicate signal type: orange = MIDI, blue = audio.

Connections are validated against real port counts read from each VST3 binary. A connection to an out-of-range port is silently rejected; check port counts with:

native/build-ui-jack-vst3/transmission_vst3_inspect ~/.vst3/<name>.vst3 \
  | grep -E 'audioInputs|audioOutputs|midiInputs|midiOutputs'

Transport

The toolbar provides Play, Stop, and BPM controls. Changes to tempo or loop range require audio to be stopped first.

Console commands

Type commands into the console text entry at the bottom of the window.

Command Output
lsp All available JACK input/output ports
connections Current JACK output connections
peaks Current output peak levels
status Runtime state and last connection error
diag Full engine diagnostics: timing, block counts, underruns
reconnect Retry JACK connections without restarting audio

Audio setup

Transmission routes its output to JACK. JACK port names that include a numeric suffix change each session; use the suffix-free form so fuzzy matching resolves them automatically:

Good: "UMC404HD 192k:playback_FL"
Bad:  "system:playback_1"

Configure output connections in ~/.config/transmission/config.ttl:

:config :defaultOutputConnections (
    "UMC404HD 192k:playback_FL"
    "UMC404HD 192k:playback_FR"
) .

Saving and loading projects

Projects are Turtle files (*.ttl) in the projects/ directory.

Action How
Save File → Save (or MCP project_save)
Open File → Open (or MCP project_open)
New File → New (or MCP project_new)

Offline rendering

Export a project to WAV without a running JACK server:

node scripts/probe-project.js projects/<name>.ttl

For full offline export:

node scripts/offline-render.js projects/<name>.ttl output.wav

Convert to MP3 with ffmpeg:

ffmpeg -i output.wav -q:a 2 output.mp3

Configuration

GTK editor: ~/.config/transmission/config.ttl
Live server: config.ttl in the project root (see config.defaults.ttl for all options)

Key live-server settings:

:config :port 7878 ;
        :bindAddress "127.0.0.1" ;
        :renderAheadBlocks 24 ;
        :processingThreads 4 .

Diagnosing audio problems

  1. Run the headless probe first — confirms the graph initialises and plugins produce signal without JACK:

    node scripts/probe-project.js projects/<name>.ttl

    Look for AUDIO node=guardian totalRms=... at the bottom. If the probe fails, a plugin likely has audioOutputs 0 in the TTL — add the correct :audioOutputs N declaration.

  2. Check JACK output: jack_lsp | grep playback

  3. Use the peaks console command — (silence — check connections) means no signal at the output.

  4. Run diag for full engine timing and underrun counts.

See Architecture → Diagnostics for more detail.

MCP usage

When transmission-live.js is running, any MCP client can connect and control the graph. See the MCP Reference for the full tool and API listing.

Quick example — list installed plugins and add a node:

# Via HTTP
curl http://127.0.0.1:7878/plugins | jq '.[] | .name'

# Via MCP (Claude or other client)
# tools: node_add, connection_add, graph_apply_changes, transport_play