Mirelo SFX 1.5

Sound effects are the last thing people automate, and it shows - most generated videos ship with silent scenes. Mirelo SFX 1.5 fixes that in either of two ways: type "a match being struck" and get an audio file, or feed it a video and get sound effects synced to what's happening on screen. Both run on Runware's cloud, so no audio model, no GPU, no VAE-of-sound to install.

How it works

An audioInference node. Two generation modes:

• Text-to-SFX: leave video empty, write a positivePrompt like "heavy rain on a tin roof," and pick a duration (1–10 seconds, default 10). The outputFormat choices include MP3/WAV/FLAC/OGG - audio only.
• Video-to-SFX (foley): give it a video (a URL or Runware-hosted UUID, max 10 seconds - a string input, not a VIDEO tensor) and it produces sound that matches the action, with settings.startOffset / settings.startOffset_value letting you jump to a point in the clip. With a video input, outputFormat flips to video containers (MP4/MOV/WEBM) - you get the clip with audio laid in.

The audioSettings socket takes a Runware Audio Settings builder node (grab it from the Runware/Params menu) if you want to control things like the speaker/voice side of generation. Otherwise the widget knobs you'll actually touch: seed for reproducibility, steps (default 25, 5–30) for quality-vs-speed, duration for length, and numberResults for variations.

Output is an audio socket (AUDIO type, thanks to the soundfile dependency the pack installs). Wire it into a node that consumes AUDIO - a VHS audio preview/save will do - or let a video node handle it. The pack degrades gracefully to a file path if the native AUDIO type isn't available.

Install

Part of ComfyUI-Runware:

cd ComfyUI/custom_nodes
git clone https://github.com/Runware/ComfyUI-Runware
pip install -r ComfyUI-Runware/requirements.txt

Restart (or ComfyUI Manager → search "Runware"). The requirements pull in soundfile, which is what gives audio its native type - if you installed the pack a while ago and audio nodes act weird, a pip install -r re-run is the fix. API key: Settings → Runware API key, RUNWARE_API_KEY, or runware auth login.

Gotchas

Each run is a paid cloud inference - the title bar shows cost. SFX models are getting good, but don't expect film-quality foley on the first take; numberResults up to 4 gives you options to pick from. And remember the video input is a string (URL/UUID), so a local clip needs hosting or a Runware upload before Mirelo can watch it.