[lingfengyao]

Summary

Related to #3832

Offline FsmnVADStreaming.inference advanced the dynamic silence schedule once per 60 s chunk. As a result, only the 1850 ms and 50 ms thresholds were used, and segmentation depended on where chunk boundaries fell (see #3832 and #3644).

This PR looks up the schedule in DetectOneFrame from the current segment's duration (cur_frm_idx - confirmed_start_frame + 1, as for max_single_segment_time). The per-chunk accumulate/reset logic in inference() is removed. dynamic_silence, silence_schedule and max_end_silence_time keep their meaning, and DynamicStreamingVAD (dynamic_silence=False) is unaffected.

Type of change

• Bug fix

Validation

• python -m compileall funasr examples tests
• test-kws-output.yml test list: 58 passed. test_realtime_ws_service.py + test_vllm_examples_contract.py: 114 passed.
• tests/test_fsmn_vad_dynamic_silence.py: the old test that asserted _dynamic_accumulated_ms is rewritten, and new tests drive DetectOneFrame directly. On unchanged main: 3 failed / 2 passed. With this PR: 5 passed.
• Real model, 离线 FSMN-VAD 动态静音阈值每 60 s 才更新一次，导致切分随前置静音变化 #3832 script (vad_example.wav with 0/10/30/50 s leading silence): 7/10/18/29 segments before, 4/4/4/4 after. 我又来了, 还是中文断句继续优化的样本 #3644 attachment: the boundary near 60 s is gone.

Notes for reviewers

Default offline segments become longer (median ~29 s on TED-LIUM, versus ~2 s before), because the schedule now works as designed. CER on concatenated AISHELL-1 improves, from 1.936% to 1.625%. If shorter defaults are preferred, I think that belongs in DEFAULT_SILENCE_SCHEDULE as a separate change.