Use shlex.split for --pp-params and update related docs.

README.md

@@ -214,7 +214,7 @@ which means you can modify it, redistribute it or use it however you like.
     --audio-quality QUALITY          Specify ffmpeg/avconv audio quality, insert a value between 0 (better) and 9 (worse) for VBR or a specific bitrate like 128K (default
                                      5)
     --recode-video FORMAT            Encode the video to another format if necessary (currently supported: mp4|flv|ogg|webm|mkv|xvid)
-    --pp-params                      Extra parameters for video post-processor. The params will be splited on spaces.
+    --pp-params                      Extra parameters for video post-processor.
     -k, --keep-video                 Keep the video file on disk after the post-processing; the video is erased by default
     --no-post-overwrites             Do not overwrite post-processed files; the post-processed files are overwritten by default
     --embed-subs                     Embed subtitles in the video (only for mkv and mp4 videos)

youtube_dl/YoutubeDL.py

@@ -261,6 +261,7 @@ class YoutubeDL(object):
     The following options are used by the post processors:
     prefer_ffmpeg:     If True, use ffmpeg instead of avconv if both are available,
                        otherwise prefer avconv.
+    pp_params:         Extra parameters for external apps, like avconv.
     """
 
     params = None

youtube_dl/__init__.py

@@ -171,8 +171,10 @@ def _real_main(argv=None):
     if opts.recodevideo is not None:
         if opts.recodevideo not in ['mp4', 'flv', 'webm', 'ogg', 'mkv', 'xvid']:
             parser.error('invalid video recode format specified')
-    if opts.pp_params is not None:
-        opts.pp_params = opts.pp_params.split()
+    if opts.pp_params is None:
+        opts.pp_params = []
+    else:
+        opts.pp_params = shlex.split(opts.pp_params)
     if opts.convertsubtitles is not None:
         if opts.convertsubtitles not in ['srt', 'vtt', 'ass']:
             parser.error('invalid subtitle format specified')

youtube_dl/options.py

@@ -689,8 +689,8 @@ def parseOpts(overrideArguments=None):
         help='Encode the video to another format if necessary (currently supported: mp4|flv|ogg|webm|mkv|xvid)')
     postproc.add_option(
         '--pp-params',
-        dest='pp_params', default=None,
-        help='Extra parameters for video post-processor. The params will be splited on spaces.')
+        dest='pp_params', default=None, metavar='ARGS',
+        help='Extra parameters for video post-processor.')
     postproc.add_option(
         '-k', '--keep-video',
         action='store_true', dest='keepvideo', default=False,

youtube_dl/postprocessor/common.py

@@ -22,7 +22,8 @@ class PostProcessor(object):
     of the chain is reached.
 
     PostProcessor objects follow a "mutual registration" process similar
-    to InfoExtractor objects.
+    to InfoExtractor objects. And it can receive parameters from CLI trough
+    --pp-params.
     """
 
     _downloader = None