Sound Cue Forge - UE5 plugin

You have a library of Sound Cues and MetaSounds is where the engine is going. There is no button that ports a cue: each one is rebuilt by hand, and the moment it is, every Blueprint, component and DataTable row still plays the old asset.

Sound Cue Forge reads every cue in the folders you name, decides cue by cue whether a faithful MetaSound equivalent exists, builds one for each cue that has it, refuses the rest and names the node that stopped it, points the assets that played the old cue at the new one, and journals every write so one command puts the project back.

What it does

Judges every cue. PORTABLE (every node has a faithful MetaSound construction), APPROXIMATED (portable with a named difference you accept with a switch), or REFUSED (the node that stopped it, and why). Wave Player, Random, Mixer, Concatenator, Modulator, Looping, a fixed Delay and a root Attenuation port. Branch, Switch, Doppler, a random delay, mono mixed with stereo and every node outside that set are refused, never half-ported.

Names the differences you would otherwise find by ear. Unreal builds every Random node with Randomize Without Replacement switched on. A cue plays every input once before any repeats; MetaSound's Random Get can hold back at most half of them, so in the port an input comes back sooner. That cue is APPROXIMATED and the finding says exactly that. A pitch-range Modulator is APPROXIMATED too: the cue draws a pitch ratio, the Wave Player takes semitones.

Builds the MetaSound Source beside each cue (<Cue>_MS), reads the built document back and compares every node class and every connection with what it built before anything is saved, then confirms the saved files through the asset registry.

Relinks safely. Blueprint variable defaults, arrays, soft references, component properties (an Audio Component's Sound), DataTable rows and Blueprint pin defaults. A property or pin typed Sound Cue cannot hold a MetaSound Source, so it is refused by name before anything is written; so is a read-only file. The type check runs again on the result before saving.

Undo byte for byte from the journal. CI gate: -FailOnCue exits 5 while any cue in scope is still referenced. An HTML report on every run.

Measured on our test project (Unreal Engine 5.8)

• A test project of 12 Sound Cues built the way the editor builds them, with waves imported from files of known length: 5 portable, 2 approximated (a default Random node, a pitch range), 5 refused (Branch, Doppler, Switch, a random delay, mono mixed with stereo). Referencers: three Blueprints (a hard pointer, an array, a soft pointer, an Audio Component, a Play Sound 2D pin) and a DataTable.
• Before the migration the CI gate exited 5: 8 of 12 cues still referenced.
• A Blueprint holding a cue in a property typed Sound Cue, and a read-only DataTable: each refused by name, exit 4, every fixture file byte-identical afterwards (sha256).
• One run ported 7 cues (each document read back, 7 confirmed on disk) and rewrote 10 references in 4 packages; 3 Blueprints compiled, 0 with errors.
• A separate editor process then loaded all 7 MetaSound Sources from disk and read every relinked property and row back: each pointed at its MetaSound, the refused cue's row untouched. 1 of 12 cues was still referenced: the refused Branch cue.
• -Undo restored 4 packages and deleted 7 created ones; the project was byte-identical to before the migration.
• 21 editor runs, 86 checks, all passing.

Requirements

• Unreal Engine 5.8, Windows (Win64). Only 5.8 has been built and run.
• Run as a commandlet: UnrealEditor-Cmd.exe <Project>.uproject -run=SCF -Help.

Limits

It ports the portable subset and says so: a cue built on Branch, Switch or a parameter-driven node stays a Sound Cue. It does not play or listen to the result; it proves the graph it built is the graph it meant to build. World Partition external actors are refused in this version.

Full documentation: Sound Cue Forge README

More Unreal tools from the same studio: MetaSound Parameter Surgeon (rename a MetaSound input and carry every Blueprint that sets it) and Material Parameter Name Surgeon. Everything else: csaf.itch.io

AI disclosure: the code and the cover art were produced with AI assistance.