reverting README, updating name of input to reflect functionality, removing Exception and replacing with assert, updating the CLI to accept a JSON string as an argument instead of file

README.md

@@ -409,11 +409,6 @@ Alternatively, refer to the [developer instructions](#developer-instructions) fo
                                      webm and mkv videos)
     --embed-thumbnail                Embed thumbnail in the audio as cover art
     --add-metadata                   Write metadata to the video file
-    --preferred-info                 References a JSON file that contains the
-                                     metadata that will be used preferentially
-                                     over the extracted metadata and upated onto
-                                     the output file. This argument will only be
-                                     utilized when add-metadata is used
     --metadata-from-title FORMAT     Parse additional metadata like song title /
                                      artist from the video title. The format
                                      syntax is the same as --output. Regular

youtube_dl/__init__.py

@@ -276,12 +276,11 @@ def _real_main(argv=None):
     # source and target containers. From this point the container won't change,
     # so metadata can be added here.
     if opts.addmetadata:
-        if hasattr(opts, 'preferredinfo'):
-            with open(opts.preferredinfo) as read_file:
-                preferredinfo = json.load(read_file)
+        if hasattr(opts, 'preferredmetadatatoembed'):
+            preferredmetadatatoembed = json.loads(opts.preferredmetadatatoembed)
             postprocessors.append({
                 'key': 'FFmpegMetadata',
-                'preferredinfo': preferredinfo,
+                'preferredmetadatatoembed': preferredmetadatatoembed,
                 })
         else:
             postprocessors.append({

youtube_dl/options.py

@@ -819,9 +819,12 @@ def parseOpts(overrideArguments=None):
         action='store_true', dest='addmetadata', default=False,
         help='Write metadata to the video file')
     postproc.add_option(
-        '--preferred-info',
-        dest='preferredinfo', metavar='FILE',
+        '--preferred-metadata-to-embed',
+        dest='preferredmetadatatoembed', metavar='JSON', type=str,
         help='Override metadata on the outputted file')
+    postproc.add_option(
+        '--preferred-metadata-json'
+    )
     postproc.add_option(
         '--metadata-from-title',
         metavar='FORMAT', dest='metafromtitle',

youtube_dl/postprocessor/ffmpeg.py

@@ -431,11 +431,13 @@ class FFmpegEmbedSubtitlePP(FFmpegPostProcessor):
 
 
 class FFmpegMetadataPP(FFmpegPostProcessor):
-    def __init__(self, downloader=None, preferredinfo=None):
+    def __init__(self, downloader=None, preferredmetadatatoembed=None):
         super(FFmpegMetadataPP, self).__init__(downloader)
-        if not (isinstance(preferredinfo, dict) or preferredinfo == None):
-            raise TypeError('preferredinfo must be a dictionary, if provided')
-        self._preferredinfo = preferredinfo
+        assert (
+            (isinstance(preferredmetadatatoembed, dict) or
+            preferredmetadatatoembed != None)
+            ), 'preferredmetadatatoembed must be a dictionary, if provided'
+        self._preferredmetadatatoembed = preferredmetadatatoembed
 
     def run(self, info):
         metadata = {}
@@ -456,7 +458,7 @@ class FFmpegMetadataPP(FFmpegPostProcessor):
                 meta_list = (meta_list,)
             if not isinstance(info_list, (list, tuple)):
                 info_list = (info_list,)
-            preferred_key = add_info(meta_list, info_list, metadata, self._preferredinfo)
+            preferred_key = add_info(meta_list, info_list, metadata, self._preferredmetadatatoembed)
             if preferred_key is None:
                 add_info(meta_list, info_list, metadata, info)