mediagoblin/media_types/video/models.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 from mediagoblin.db.base import Base
  19
  20 from sqlalchemy import (
  21     Column, Integer, SmallInteger, ForeignKey)
  22 from sqlalchemy.orm import relationship, backref
  23 from mediagoblin.db.extratypes import JSONEncoded
  24 from mediagoblin.media_types import video
  25
  26
  27 BACKREF_NAME = "video__media_data"
  28
  29
  30 class VideoData(Base):
  31     """
  32     Attributes:
  33      - media_data: the originating media entry (of course)
  34      - width: width of the transcoded video
  35      - height: height of the transcoded video
  36      - orig_metadata: A loose json structure containing metadata gstreamer
  37          pulled from the original video.
  38          This field is NOT GUARANTEED to exist!
  39
  40          Likely metadata extracted:
  41            "videoheight", "videolength", "videowidth",
  42            "audiorate", "audiolength", "audiochannels", "audiowidth",
  43            "mimetype", "tags"
  44
  45          TODO: document the above better.
  46     """
  47     __tablename__ = "video__mediadata"
  48
  49     # The primary key *and* reference to the main media_entry
  50     media_entry = Column(Integer, ForeignKey('core__media_entries.id'),
  51         primary_key=True)
  52     get_media_entry = relationship("MediaEntry",
  53         backref=backref(BACKREF_NAME, uselist=False,
  54                         cascade="all, delete-orphan"))
  55
  56     width = Column(SmallInteger)
  57     height = Column(SmallInteger)
  58
  59     orig_metadata = Column(JSONEncoded)
  60
  61     def source_type(self):
  62         """
  63         Construct a useful type=... that is to say, used like:
  64           <video><source type="{{ entry.media_data.source_type() }}" /></video>
  65
  66         Try to construct it out of self.orig_metadata... if we fail we
  67         just dope'ily fall back on DEFAULT_WEBM_TYPE
  68         """
  69         orig_metadata = self.orig_metadata or {}
  70
  71         if ("webm_video" not in self.get_media_entry.media_files
  72            and "mimetype" in orig_metadata['common']['tags']
  73            and "codec" in orig_metadata['audio']
  74            and "codec" in orig_metadata['video']):
  75             if orig_metadata['mimetype'] == 'application/ogg':
  76                 # stupid ambiguous .ogg extension
  77                 mimetype = "video/ogg"
  78             else:
  79                 mimetype = orig_metadata['common']['tags']['mimetype']
  80
  81             video_codec = orig_metadata["video"]["codec"].lower()
  82             audio_codec = orig_metadata["audio"]["codec"].lower()
  83
  84             # We don't want the "video" at the end of vp8...
  85             # not sure of a nicer way to be cleaning this stuff
  86             if video_codec == "vp8 video":
  87                 video_codec = "vp8"
  88
  89             return '%s; codecs="%s, %s"' % (
  90                 mimetype, video_codec, audio_codec)
  91         else:
  92             return video.VideoMediaManager.default_webm_type
  93
  94
  95 DATA_MODEL = VideoData
  96 MODELS = [VideoData]