add readme

README.md

@@ -1,2 +1,68 @@
-# ffmpeg
+### Description
+
+---
+
+**Audio** **Decode** converts the encoded audio back to uncompressed audio frames. In most cases, audio decoding is the first step of an audio processing pipeline.
+
+
+
+### Interface
+
+---
+
+def audio_decode.${op_name}(**kwargs):
+
+def ${op_name}.__call__(audio)
+
+"""
+
+An audio decode operator takes an audio file path as input. It decodes the audio back to audio frames.
+
+**Args:**
+
+**audio** (str):
+
+Audio file path.
+
+**Return** (iterable):
+
+An iterator over audio frames with type `towhee.types.AudioFrame`.
+
+"""
+
+### Code Example
+
+
+
+Using the default audio_decode implementation and writing the pipeline in the simplified way
+
+```Python
+import towhee.DataCollection as dc
+
+
+
+dc.glob(./music.flac)
+
+  .audio_decode()
+
+  .show()
+```
+
+
+
+Using the ffmpeg based implementations of audio_decode to write a same pipeline
+
+```Python
+import towhee.DataCollection as dc
+
+
+
+dc.glob['path'](./music.flac)
+
+  .audio_decode.ffmpeg['path', 'frames']()
+
+  .select('frames')
+
+  .show()
+```