Video + Audio Combiner (Simple)

You've rendered a video and you need a soundtrack on it. That's a five-second ffmpeg command you've typed so many times you could do it blind - but in a ComfyUI graph you can't, so here's the node. Video Audio Combiner (Simple) takes a video file path and an audio file path, and muxes the audio onto the video using ffmpeg. The "simple" in the name is doing real work: no node-type gymnastics, no waveform inputs, just two file paths in and one path out. It's the file-path version of the pack's audio-combiner family, and it's the one I'd grab first for a quick mux.

The headline feature is that it stream-copies the video track (-c:v copy), which means zero re-encoding of your footage - the pixels pass through untouched and the whole operation is fast. The audio gets encoded to AAC at 192k, which is a sensible default for a soundtrack. If you care about keeping your video generation results bit-exact, this is the gentle option.

How it works

The node probes the video's duration from ffmpeg's output, then builds a command that maps video stream 0 and audio stream 1, trims (and optionally loops) the audio to exactly match the video length, and writes the result to ComfyUI's output directory as output_filename.mp4. The trim behavior is worth knowing: the audio is cut to the video's duration, so a long music track gets clipped to the clip - and with loop_audio on, a short track repeats to fill the whole thing. audio_start_seconds lets you skip ahead in the audio file before trimming, so you can start the music at a specific moment rather than from the top.

The inputs that matter

• video_path - path to your video (mp4, mkv, avi - whatever ffmpeg can read).
• audio_path - path to the audio file.
• audio_start_seconds (default 0) - where in the audio to start.
• loop_audio (boolean) - loop a too-short track to fill the video.
• output_filename (default output_with_audio) - saved into ComfyUI's output folder.

The single output, output_path, is the full path to the new file - an output node, so it ends the graph and just reports where the file went.

Install

Manager → search AnotherUtils, or:

cd ComfyUI/custom_nodes
git clone https://github.com/marcoc2/ComfyUI-AnotherUtils.git

Restart. The one real dependency is ffmpeg itself: the node tries to use Video Helper Suite's bundled ffmpeg if you have VHS installed, otherwise falls back to ffmpeg on your system PATH. If you get "ffmpeg failed" errors, make sure you have one or the other.

Common issues

A missing file raises a clear ValueError (good), but a missing ffmpeg binary raises a cryptic subprocess error (less good) - install VHS or add ffmpeg to your PATH first. Watch the loop behavior: loop_audio uses an infinite-loop filter then trims, which is fine, but if you enable it on an audio file longer than the video, the trim still cuts it to length, so you're safe there. And remember the output goes to ComfyUI's output directory with your chosen name - don't expect it next to your input files.