use ffmpeg to transcode audio

Author: brendan-stripe

beetsplug/beetstream/songs.py

@@ -1,6 +1,5 @@
 from beetsplug.beetstream.utils import *
-from beetsplug.beetstream.stream import stream
-from beetsplug.beetstream import app
+from beetsplug.beetstream import app, stream
 from flask import g, request, Response
 from beets.random import random_objs
 import xml.etree.cElementTree as ET
@@ -54,15 +53,18 @@ def stream_song():
     id = int(song_subid_to_beetid(request.values.get('id')))
     item = g.lib.get_item(id)
 
-    return stream(item.path.decode('utf-8'), maxBitrate)
+    if maxBitrate > 0 and item.bitrate > maxBitrate * 1000:
+        return stream.try_to_transcode(item.path.decode('utf-8'), maxBitrate)
+    else:
+        return stream.send_raw_file(item.path.decode('utf-8'))
 
 @app.route('/rest/download', methods=["GET", "POST"])
 @app.route('/rest/download.view', methods=["GET", "POST"])
 def download_song():
     id = int(song_subid_to_beetid(request.values.get('id')))
     item = g.lib.get_item(id)
 
-    return stream(item.path.decode('utf-8'), 0)
+    return stream.send_raw_file(item.path.decode('utf-8'))
 
 @app.route('/rest/getRandomSongs', methods=["GET", "POST"])
 @app.route('/rest/getRandomSongs.view', methods=["GET", "POST"])

beetsplug/beetstream/stream.py

@@ -1,8 +1,20 @@
 from beetsplug.beetstream.utils import path_to_content_type
 from flask import send_file, Response
 
+import ffmpeg
+
 def send_raw_file(filePath):
     return send_file(filePath, mimetype=path_to_content_type(filePath))
 
-def stream(filePath, maxBitrate):
-    return send_raw_file(filePath)
+def transcode_and_stream(filePath, maxBitrate):
+    outputStream = (
+        ffmpeg
+        .input(filePath)
+        .output('pipe:', format="mp3", audio_bitrate=maxBitrate * 1000)
+        .run_async(pipe_stdout=True)
+    )
+
+    return Response(outputStream.stdout, mimetype='audio/mpeg')
+
+def try_to_transcode(filePath, maxBitrate):
+    return transcode_and_stream(filePath, maxBitrate)