Add a PostProcessor for adding metadata to the file (closes #1570)

It currently sets the title, the date and the author values.

youtube_dl/PostProcessor.py

@@ -2,6 +2,7 @@
 import subprocess
 import sys
 import time
+import datetime
 
 from .utils import *
 
@@ -467,3 +468,35 @@ def run(self, information):
         os.rename(encodeFilename(temp_filename), encodeFilename(filename))
 
         return True, information
+
+
+class FFmpegMetadataPP(FFmpegPostProcessor):
+    def run(self, info):
+        metadata = {}
+        if info.get('title') is not None:
+            metadata['title'] = info['title']
+        if info.get('upload_date') is not None:
+            metadata['date'] = info['upload_date']
+        if info.get('uploader') is not None:
+            metadata['artist'] = info['uploader']
+        elif info.get('uploader_id') is not None:
+            metadata['artist'] = info['uploader_id']
+
+        if not metadata:
+            self._downloader.to_screen(u'[ffmpeg] There isn\'t any metadata to add')
+            return True, info
+
+        filename = info['filepath']
+        ext = os.path.splitext(filename)[1][1:]
+        temp_filename = filename + u'.temp'
+
+        options = ['-c', 'copy']
+        for (name, value) in metadata.items():
+            options.extend(['-metadata', '%s="%s"' % (name, value)])
+        options.extend(['-f', ext])
+
+        self._downloader.to_screen(u'[ffmpeg] Adding metadata to \'%s\'' % filename)
+        self.run_ffmpeg(filename, temp_filename, options)
+        os.remove(encodeFilename(filename))
+        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
+        return True, info

youtube_dl/__init__.py

@@ -358,6 +358,8 @@ def _hide_login_info(opts):
             help='do not overwrite post-processed files; the post-processed files are overwritten by default')
     postproc.add_option('--embed-subs', action='store_true', dest='embedsubtitles', default=False,
             help='embed subtitles in the video (only for mp4 videos)')
+    postproc.add_option('--add-metadata', action='store_true', dest='addmetadata', default=False,
+            help='add metadata to the files')
 
 
     parser.add_option_group(general)
@@ -651,6 +653,9 @@ def _real_main(argv=None):
     ydl.add_default_info_extractors()
 
     # PostProcessors
+    # Add the metadata pp first, the other pps will copy it
+    if opts.addmetadata:
+        ydl.add_post_processor(FFmpegMetadataPP())
     if opts.extractaudio:
         ydl.add_post_processor(FFmpegExtractAudioPP(preferredcodec=opts.audioformat, preferredquality=opts.audioquality, nopostoverwrites=opts.nopostoverwrites))
     if opts.recodevideo: