merge pull request #56 (thread count detection)

beetsplug/convert.py

@@ -16,6 +16,7 @@
 """
 import logging
 import os
+import sys
 import shutil
 from subprocess import Popen, PIPE
 
@@ -28,6 +29,32 @@ DEVNULL = open(os.devnull, 'wb')
 conf = {}
 
 
+def _cpu_count():
+    """ Returns the number of CPUs in the system.
+    Code was adapted from observing the soundconverter project:
+    https://github.com/kassoulet/soundconverter
+    """
+    if sys.platform == 'win32':
+        try:
+            num = int(os.environ['NUMBER_OF_PROCESSORS'])
+        except (ValueError, KeyError):
+            num = 0
+    elif sys.platform == 'darwin':
+        try:
+            num = int(os.popen('sysctl -n hw.ncpu').read())
+        except ValueError:
+            num = 0
+    else:
+        try:
+            num = os.sysconf('SC_NPROCESSORS_ONLN')
+        except (ValueError, OSError, AttributeError):
+            num = 0
+    if num >= 1:
+        return num
+    else:
+        return 1
+
+
 def encode(source, dest):
     log.info('Started encoding ' + source)
     temp_dest = dest + '~'
@@ -116,7 +143,8 @@ def convert_func(lib, config, opts, args):
 class ConvertPlugin(BeetsPlugin):
     def configure(self, config):
         conf['dest'] = ui.config_val(config, 'convert', 'dest', None)
-        conf['threads'] = ui.config_val(config, 'convert', 'threads', 2)
+        conf['threads'] = ui.config_val(config, 'convert', 'threads',
+            _cpu_count())
         conf['flac'] = ui.config_val(config, 'convert', 'flac', 'flac')
         conf['lame'] = ui.config_val(config, 'convert', 'lame', 'lame')
         conf['opts'] = ui.config_val(config, 'convert',
@@ -131,7 +159,8 @@ class ConvertPlugin(BeetsPlugin):
         cmd.parser.add_option('-a', '--album', action='store_true',
                               help='choose albums instead of tracks')
         cmd.parser.add_option('-t', '--threads', action='store', type='int',
-                              help='change the number of threads (default 2)')
+                              help='change the number of threads, \
+                              defaults to maximum availble processors ')
         cmd.parser.add_option('-d', '--dest', action='store',
                               help='set the destination directory')
         cmd.func = convert_func

docs/plugins/convert.rst

@@ -49,7 +49,8 @@ The plugin offers several configuration options, all of which live under the
 * ``opts`` are the encoding options that are passed to ``lame``. Default: 
   "-V2". Please refer to the LAME documentation for possible options.
 * Finally, ``threads`` determines the number of threads to use for parallel
-  encoding. Default: 2.
+  encoding. By default, the plugin will detect the number of processors
+  available and use them all.
 
 Here's an example configuration::