Summary
In Unreal Engine 5.8, Movie Render Queue cannot begin rendering when an active Niagara System uses the Audio Spectrum Data Interface.
As soon as Local Render or Remote Render is started, the render window opens but the process never reaches the first frame. The Unreal Editor becomes completely unresponsive, while CPU and GPU usage remain close to zero.
Removing or disabling Audio Spectrum immediately resolves the issue and Movie Render Queue works normally.
The issue is reproducible in a completely blank UE 5.8 project using newly created assets. The same Audio Spectrum and Movie Render Queue workflow worked correctly in Unreal Engine 5.7.
What Type of Bug are you experiencing?
Rendering (Graphics / Niagara)
Steps to Reproduce
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Create a new blank Unreal Engine 5.8 project.
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Create a new empty level.
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Create a new Niagara System using a simple emitter.
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Create a new Niagara Scratch Pad module.
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Add an Audio Spectrum Data Interface parameter to the Scratch Pad module.
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Read or sample data from the Audio Spectrum Data Interface inside the module.
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Add the Scratch Pad module to the Niagara emitter.
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Place the Niagara System in the level and make sure the Niagara component is active.
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Add a Sound Wave or another audio source to the level or Level Sequence.
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Create a new Level Sequence with a Cine Camera and a Camera Cuts track.
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Add the Level Sequence to Movie Render Queue.
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Use a basic render configuration, such as Deferred Rendering with PNG or EXR output.
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Start either Local Render or Remote Render.
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Observe that the render process freezes before producing the first frame.
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Remove or disable the Audio Spectrum Data Interface from the Niagara System.
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Start the same Movie Render Queue job again.
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Observe that rendering now starts and completes normally.
Expected Result
Movie Render Queue should initialize the Niagara System, process the Audio Spectrum Data Interface and begin rendering normally.
The Niagara effect should react to the audio during the render, as it did with the same workflow in Unreal Engine 5.7.
The presence of an active Audio Spectrum Data Interface should not prevent Movie Render Queue from reaching or rendering the first frame.
Observed Result
Movie Render Queue does not reach the first frame when an active Niagara Audio Spectrum Data Interface is present.
With Local Render, a blank render window opens and the entire Unreal Editor becomes unresponsive.
With Remote Render, the separate render process loads the map and initializes the camera and render pass, but rendering stops before the first frame is produced.
CPU and GPU usage remain close to zero after the freeze, indicating that the render is not progressing.
The final relevant log messages include the Niagara audio listener being registered, for example:
NiagaraAudioSamplingListener registered with submix ‘MasterSubmixDefault’
No fatal error or crash message is produced. The process remains frozen until it is manually terminated.
Removing or disabling Audio Spectrum allows the exact same Movie Render Queue job to render normally.
The issue also occurs in a completely new blank UE 5.8 project with newly created Niagara, Scratch Pad, Level Sequence and Movie Render Queue assets. Therefore, it does not appear to be caused by migrated assets, project configuration, Grid3D fluids, render settings or a specific existing project.
Affects Versions
5.8
Platform(s)
Windows
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Additional Notes
This is a freeze/hang rather than a crash, so no Crash Reporter window or callstack is generated.
The Unreal Editor or remote render process remains unresponsive indefinitely and must be terminated manually through Task Manager.
The issue reproduces in a completely blank Unreal Engine 5.8 project. The same workflow worked correctly in Unreal Engine 5.7.
Removing or disabling the Niagara Audio Spectrum Data Interface immediately allows Movie Render Queue to render normally.