Add layout in output

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

audio_decoder.py

@@ -5,7 +5,13 @@ import av
 from towhee.operator.base import Operator
 
 
-AudioOutput = NamedTuple("Outputs", [("audio_frame", 'ndarray'), ('sample_rate', 'int'), ("TIMESTAMP", 'int')])
+AudioOutput = NamedTuple(
+    "Outputs",
+    [("audio_frame", 'ndarray'),
+     ('sample_rate', 'int'),
+     ('layout', 'str'),
+     ("TIMESTAMP", 'int')]
+)
 
 
 class AudioDecoder(Operator):
@@ -21,5 +27,6 @@ class AudioDecoder(Operator):
         for frame in in_container.decode(stream):
             timestamp = int(frame.time * 1000)
             sample_rate = frame.sample_rate
+            layout = frame.layout.name
             ndarray = frame.to_ndarray()
-            yield AudioOutput(ndarray, sample_rate, timestamp)
+            yield AudioOutput(ndarray, sample_rate, layout, timestamp)