fix: disable duplicate dynamic silence logic in DynamicStreamingVAD (#3240)

* fix: forward silence_schedule to streaming FSMN-VAD

* fix: forward silence_schedule to streaming FSMN-VAD

* style: remove debug comment

* fix: disable duplicate dynamic silence logic in DynamicStreamingVAD

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* fix(vad): initialize dynamic thresholds on first feed

Pass the wrapper silence and noise thresholds into the initial FSMN-VAD cache so first-call behavior does not depend on caller chunking. Add a regression that exercises the wrapper with the production cache initializer.

Assisted-by: Codex:gpt-5.6

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: zhifu gao <[email protected]>

funasr/models/fsmn_vad_streaming/dynamic_vad.py

@@ -130,10 +130,18 @@ class DynamicStreamingVAD:
         self.accumulated_since_cut_ms += int(chunk_samples * 1000 / self.sample_rate)
 
         self._apply_dynamic_threshold()
+        initial_cache_kwargs = {}
+        if "stats" not in self.cache:
+            initial_cache_kwargs = {
+                "max_end_silence_time": self._get_silence_threshold(),
+                "speech_noise_thres": self.speech_noise_thres,
+            }
 
         res = self.model.generate(
             input=[audio_chunk], cache=self.cache,
             is_final=is_final, chunk_size=self.chunk_size_ms,
+            dynamic_silence=False,
+            **initial_cache_kwargs,
         )
 
         signals = res[0].get("value", [])

funasr/models/fsmn_vad_streaming/model.py

@@ -871,7 +871,9 @@ class FsmnVADStreaming(nn.Module):
             sil_pdf_ids=self.vad_opts.sil_pdf_ids,
             max_end_sil_frame_cnt_thresh=self.vad_opts.max_end_silence_time
             - self.vad_opts.speech_to_sil_time_thres,
-            speech_noise_thres=self.vad_opts.speech_noise_thres,
+            speech_noise_thres=kwargs.get(
+                "speech_noise_thres", self.vad_opts.speech_noise_thres
+            ),
         )
         cache["windows_detector"] = windows_detector
         cache["stats"] = stats

tests/test_dynamic_streaming_vad.py

@@ -0,0 +1,86 @@
+import unittest
+from types import SimpleNamespace
+
+import torch
+
+from funasr.models.fsmn_vad_streaming import model as vad_model
+from funasr.models.fsmn_vad_streaming.dynamic_vad import DynamicStreamingVAD
+
+
+class _ThresholdAwareModel:
+    """Small AutoModel stand-in that uses the production cache initializer."""
+
+    sample_rate = 16000
+
+    def __init__(self):
+        self.model = vad_model.FsmnVADStreaming.__new__(vad_model.FsmnVADStreaming)
+        self.model.vad_opts = SimpleNamespace(
+            window_size_ms=200,
+            sil_to_speech_time_thres=150,
+            speech_to_sil_time_thres=150,
+            frame_in_ms=10,
+            sil_pdf_ids=[0],
+            max_end_silence_time=800,
+            speech_noise_thres=0.5,
+        )
+
+    def generate(self, input, cache, **kwargs):
+        if not cache:
+            self.model.init_cache(cache, **kwargs)
+
+        audio = torch.cat((cache.get("_test_audio", torch.empty(0)), input[0]))
+        cache["_test_audio"] = audio
+
+        speech_indices = torch.nonzero(audio.abs() > 0.5)
+        if not len(speech_indices) or cache.get("_test_emitted"):
+            return [{"value": []}]
+
+        last_speech_sample = speech_indices[-1].item()
+        trailing_silence_ms = int(
+            (len(audio) - last_speech_sample - 1) * 1000 / self.sample_rate
+        )
+        stats = cache["stats"]
+        threshold_ms = (
+            stats.max_end_sil_frame_cnt_thresh
+            + self.model.vad_opts.speech_to_sil_time_thres
+        )
+        if trailing_silence_ms < threshold_ms:
+            return [{"value": []}]
+
+        cache["_test_emitted"] = True
+        speech_end_ms = int((last_speech_sample + 1) * 1000 / self.sample_rate)
+        return [{"value": [[0, speech_end_ms]]}]
+
+
+class TestDynamicStreamingVadFirstCall(unittest.TestCase):
+    def _new_vad(self):
+        return DynamicStreamingVAD(
+            _ThresholdAwareModel(),
+            silence_schedule=[(float("inf"), 10000)],
+            speech_noise_thres=0.73,
+        )
+
+    def test_first_feed_initializes_wrapper_thresholds(self):
+        vad = self._new_vad()
+
+        vad.feed(torch.ones(960))
+
+        self.assertEqual(vad.cache["stats"].max_end_sil_frame_cnt_thresh, 9850)
+        self.assertAlmostEqual(vad.cache["stats"].speech_noise_thres, 0.73)
+
+    def test_first_feed_is_chunking_invariant(self):
+        audio = torch.cat((torch.ones(16000), torch.zeros(32000)))
+
+        one_chunk_vad = self._new_vad()
+        one_chunk_segments = one_chunk_vad.feed(audio)
+
+        split_vad = self._new_vad()
+        split_segments = split_vad.feed(audio[:960])
+        split_segments.extend(split_vad.feed(audio[960:]))
+
+        self.assertEqual(one_chunk_segments, split_segments)
+        self.assertEqual(one_chunk_segments, [])
+
+
+if __name__ == "__main__":
+    unittest.main()