diff --git a/ffmpeg/asyncio/ffmpeg.py b/ffmpeg/asyncio/ffmpeg.py
index 6bedec9..d104d2f 100644
--- a/ffmpeg/asyncio/ffmpeg.py
+++ b/ffmpeg/asyncio/ffmpeg.py
@@ -255,11 +255,12 @@ async def _read_stdout(self) -> bytes:
     async def _handle_stderr(self) -> str:
         assert self._process.stderr is not None
 
-        line = b""
-        async for line in readlines(self._process.stderr):
-            self.emit("stderr", line.decode())
+        line = ""
+        async for line_bytes in readlines(self._process.stderr):
+            line = line_bytes.decode(errors="backslashreplace")
+            self.emit("stderr", line)
 
-        return line.decode()
+        return line
 
     def _reraise_exception(self, exception: Exception):
         raise exception
diff --git a/ffmpeg/ffmpeg.py b/ffmpeg/ffmpeg.py
index 36a8c73..940c953 100644
--- a/ffmpeg/ffmpeg.py
+++ b/ffmpeg/ffmpeg.py
@@ -251,9 +251,10 @@ def _read_stdout(self) -> bytes:
     def _handle_stderr(self) -> str:
         assert self._process.stderr is not None
 
-        line = b""
-        for line in readlines(self._process.stderr):
-            self.emit("stderr", line.decode())
+        line = ""
+        for line_bytes in readlines(self._process.stderr):
+            line = line_bytes.decode(errors="backslashreplace")
+            self.emit("stderr", line)
 
         self._process.stderr.close()
-        return line.decode()
+        return line