possible example for frame_process_method

Author: irmen

README.md

@@ -279,8 +279,8 @@ this generator as a stream source.  The data can be provided in ``array`` type o
 the audio data has, and the sample with in bytes.
 
 
-*function*  ``stream_with_callbacks  (sample_stream: Generator[Union[bytes, array.array], int, NoneType], progress_callback: Optional[Callable[[int], NoneType]] = None, frame_process_method: Union[Callable[[array.array], None], None] = None, end_callback: Optional[Callable] = None) -> Generator[Union[bytes, array.array], int, NoneType]``
-> Convenience generator function to add callback and processing functionality to another stream. You can specify a:
+*function*  ``stream_with_callbacks  (sample_stream: Generator[Union[bytes, array.array], int, NoneType], progress_callback: Optional[Callable[[int], NoneType]] = None, frame_process_method: Union[Callable[[array.array], array.array], None] = None, end_callback: Optional[Callable] = None) -> Generator[Union[bytes, array.array], int, NoneType]``
+> Convenience generator function to add callback and processing functionality to another stream. You can specify:
 A callback function that gets called during play and takes an ``int``
 for the number of frames played.
 A function that can be used to process raw data frames before they are yielded back

examples/playcallbacks.py

@@ -4,6 +4,7 @@
 
 import sys
 import miniaudio
+import array
 
 
 def stream_end_callback() -> None:
@@ -14,11 +15,18 @@ def stream_progress_callback(framecount: int) -> None:
     print(framecount, ",", end="", flush=True)
 
 
+def process_method(samples: array.array) -> array.array:
+    # For example: silence the left stereo channel:
+    # for i in range(0, len(samples), 2):
+    #    samples[i] = 0
+    return samples
+
+
 if __name__ == "__main__":
     if len(sys.argv) != 2:
         raise SystemExit("use one argument: filename")
     filestream = miniaudio.stream_file(sys.argv[1])
-    callbacks_stream = miniaudio.stream_with_callbacks(filestream, stream_progress_callback, stream_end_callback)
+    callbacks_stream = miniaudio.stream_with_callbacks(filestream, stream_progress_callback, process_method, stream_end_callback)
     next(callbacks_stream)  # start the generator
     with miniaudio.PlaybackDevice() as device:
         print("playback in background. press enter to exit:\n")

miniaudio.py

@@ -1268,7 +1268,7 @@ def on_close() -> None:
 
 def stream_with_callbacks(sample_stream: PlaybackCallbackGeneratorType,
                           progress_callback: Union[Callable[[int], None], None] = None,
-                          frame_process_method: Union[Callable[[array.array], None], None] = None,
+                          frame_process_method: Union[Callable[[array.array], array.array], None] = None,
                           end_callback: Union[Callable, None] = None) -> PlaybackCallbackGeneratorType:
     """
     Convenience generator function to add callback and processing functionality to another stream.