diff --git a/extension/audio/mel_spectrogram.py b/extension/audio/mel_spectrogram.py
index 50b9ded01af..4d7180854f1 100644
--- a/extension/audio/mel_spectrogram.py
+++ b/extension/audio/mel_spectrogram.py
@@ -192,10 +192,15 @@ def export_processor(model=None, output_file="whisper_preprocess.pte"):
     if model is None:
         model = WhisperAudioProcessor()
 
-    audio_tensor = torch.randn(93680)
+    if model.streaming:
+        # Streaming processes small windows per step. 2 seconds gives
+        # comfortable headroom while keeping the memory plan tight.
+        max_samples = 2 * model.sampling_rate
+    else:
+        max_samples = model.max_audio_len * model.sampling_rate
+    audio_tensor = torch.randn(min(93680, max_samples))
     shapes_collection = torch.export.ShapesCollection()
-    max_n_chunks = int(model.max_audio_len * model.n_samples)
-    shapes_collection[audio_tensor] = {0: Dim.DYNAMIC(max=max_n_chunks)}
+    shapes_collection[audio_tensor] = {0: Dim.DYNAMIC(max=max_samples)}
     with torch.no_grad(), torch.fx.experimental._config.patch(
         backed_size_oblivious=True
     ):