support batch

Signed-off-by: junjie.jiang <junjie.jiang@zilliz.com>

__init__.py

@@ -1,5 +1,5 @@
 from .audio_decoder_ffmpeg import AudioDecoderFFmpeg
 
 
-def ffmpeg():
-    return AudioDecoderFFmpeg()
+def ffmpeg(batch_size=-1):
+    return AudioDecoderFFmpeg(batch_size)

audio_decoder_ffmpeg.py

@@ -11,15 +11,30 @@ class AudioDecoderFFmpeg(PyOperator):
     """
     """
 
-    def __init__(self) -> None:
+    def __init__(self, batch_size=-1) -> None:
         super().__init__()
+        self._batch_size = batch_size
 
     def __call__(self, audio_path: str):
+        frames = []
         in_container = av.open(audio_path)
         stream = in_container.streams.get(audio=0)[0]        
+        if self._batch_size <= 0:
             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 AudioFrame(ndarray, sample_rate, timestamp, layout)
+        else:
+            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()
+                frames.append(AudioFrame(ndarray, sample_rate, timestamp, layout))
+                if len(frames) == self._batch_size:
+                    yield frames
+                    frames = []
+            if len(frames) != 0:
+                yield frames