diff --git a/gnommo/renderer.py b/gnommo/renderer.py
index 8451b32..2868fc7 100644
--- a/gnommo/renderer.py
+++ b/gnommo/renderer.py
@@ -364,11 +364,20 @@ def build_ffmpeg_command(plan: RenderPlan, output_path: Path) -> list[str]:
 
     # Global thread limits before any -i. Without this, each format=rgba conversion
     # in the filter graph (one per video layer) spawns one swscaler thread per CPU core,
-    # causing OOM on Apple Silicon where av_cpu_count() returns 10-11.
+    # causing OOM on Apple Silicon where av_cpu_count() returns 10-11 — and OOM-killing
+    # the whole WSL2 VM on Windows (Wsl/Service/E_UNEXPECTED), since the VM's RAM is
+    # capped well below the host's.
+    #
+    # CRITICAL: this render uses -filter_complex, whose parallelism is governed by
+    # -filter_complex_threads. -filter_threads only applies to SIMPLE (-vf) graphs and
+    # is silently ignored here, so without -filter_complex_threads the graph runs one
+    # thread per core no matter what — the real cause of the render-stage memory blowup.
     from .cache import get_ffmpeg_thread_count
 
     _tc = str(get_ffmpeg_thread_count())
-    cmd.extend(["-threads", _tc, "-filter_threads", _tc])
+    cmd.extend(
+        ["-threads", _tc, "-filter_threads", _tc, "-filter_complex_threads", _tc]
+    )
 
     # Resolve paths to absolute
     project_path = plan.project_path.resolve()