Save Audio Smart Prefix

This is the release end of the whole pipeline, the node where a folder of AI tracks becomes something you could actually upload. Save Audio Smart Prefix is the pack's flagship saver: it writes FLAC/MP3/WAV to smart relative paths (normally fed by MiniMax Output Paths), names files [Album] - [Title].flac, embeds standard tags, embeds your cover art at a controlled resolution, and writes the reproducibility JSON sidecar next to the audio. It's the "finish the release" node, and it's an output node - the chain ends here.

The [Album] - [Title] naming is worth calling out because it's the kind of small decision that separates a release from a pile of files: the filesystem name comes from the Album and Title tags, while the embedded Title metadata stays just the song title. Clean names for humans, clean tags for players, and the sidecar holds everything else.

Inputs that matter

• audio - the final mastered signal.
• filename_prefix - normally the prefix from MiniMax Output Paths; the node appends extension and collision suffix.
• format - flac (default), mp3, wav. Plus mp3_quality, flac_bit_depth, wav_bit_depth, and peak_handling, same set as the absolute-path saver.
• collision_mode / create_directories - same guards as its sibling.
• write_json_sidecar (default true) - writes the connected metadata_json next to the audio. Keep it on; this is the reproducibility payoff.
• embed_basic_metadata (default true) - embeds the audio_tags_json tags in formats that support them.

The interesting optional inputs: metadata_json (from MiniMax Song Metadata), audio_tags_json (from MiniMax Standard Audio Tags), cover_image_path (the cover JPG - the source file is never modified, only a JPEG copy is embedded), filename_mode (album - title default, title only, or prefix as provided), and embedded_cover_size (default 512; the workflow links it to MiniMax Square Image Size, so a 1024 cover can embed at 1024). The tooltip's advice is worth taking: some older players prefer 512 or 1024, and bigger art makes bigger files.

Outputs

audio (passthrough), saved_path, and metadata_path (where the sidecar landed).

Installing it

Pack install via ComfyUI Manager (search "MiniMax Music Production Toolkit") or:

cd ComfyUI/custom_nodes
git clone https://github.com/jplenio/ComfyUI-MiniMax-Music-Production-Toolkit.git
cd ComfyUI-MiniMax-Music-Production-Toolkit
python -m pip install -r requirements.txt

Dependencies: scipy, soundfile, imageio-ffmpeg, mutagen, Pillow - mutagen does the tags/cover embedding. Restart ComfyUI and hard-refresh once.

Gotchas

If the sidecar doesn't appear, write_json_sidecar is off or metadata_json was never connected - the node can't write a sidecar it was never given. If embedded art looks wrong, check embedded_cover_size and remember it's a square target: a non-square source gets treated as a square, so keep art 1:1. And the filename_mode only changes the filesystem name, never the metadata Title - if your files are named oddly, that's where to look before you go hunting through the whole workflow.