diff --git a/demucs_pipeline.py b/demucs_pipeline.py
index fc0f0c6..716b20f 100644
--- a/demucs_pipeline.py
+++ b/demucs_pipeline.py
@@ -348,6 +348,9 @@ def run_demucs_pipeline(
                     break
                 continue
 
+            # proc_v 的 stderr 为 bytes，需解码为 str
+            if isinstance(line, bytes):
+                line = line.decode("utf-8", errors="replace")
             line = line.strip()
             if line.startswith("__ERR__READER__"):
                 print(f"[ERROR] stderr reader 异常: {line}")