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Won't Fix
Votes
2
Found in
6000.0.60f1
6000.2.8f1
6000.3.0b7
6000.4.0a3
Issue ID
UUM-122520
Regression
No
Audio stuttering occurs when heavy processing is performed while OnAudioFilterRead is in use
Reproduction steps:
1. Open the attached “IN-118833.zip” project
2. Open the “SampleScene”
3. Enter Play mode
4. Listen to the audio
Expected result: Audio plays smoothly
Actual result: Audio playback is stuttering intermittently
Reproducible with: 2023.1.0b1, 6000.0.60f1, 6000.2.8f1, 6000.3.0b7, 6000.4.0a3
Reproducible on: Windows 11
Not reproducible on: No other environment tested
Notes:
- Simply increasing CPU load did not reproduce this issue (e.g., writing a large number of Debug.Log statements)
- The issue can be reproduced reliably by manually invoking System.GC.Collect
- In the provided sample scene, a script calls System.GC.Collect once per second to reproduce the issue
Comments (1)
-
biddiBytes_unity
Oct 21, 2025 15:16
OnAudioFilterRead is designed so that the audio thread gets attached to the scripting thread and is therefore susceptible to GC interrupts. There is ongoing work to fix this with a new system, which we have started releasing incrementally in 6.3 that addresses this design flaw, so we don't foresee us fixing this issue. See this discussion thread for more information: https://discussions.unity.com/t/audio-status-update-q3-2025/1681867/
And thanks for reporting!
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Resolution Note:
OnAudioFilterRead is designed so that the audio thread gets attached to the scripting thread and is therefore susceptible to GC interrupts. There is ongoing work to fix this with a new system, which we have started releasing incrementally in 6.3 that addresses this design flaw, so we don't foresee us fixing this issue. See this discussion thread for more information: https://discussions.unity.com/t/audio-status-update-q3-2025/1681867/
And thanks for reporting!