Determine episode duration (bug 811)

This patch adds two methods for detecting the
episode length (time units, not bytes):

 * iTunes-specific "duration" in the RSS feed
 * GStreamer-based length detection after download

The patch also adds duration information to the
tooltip in the episode list as a first step for
displaying this information in the UI.

src/gpodder/gtkui/model.py

@@ -237,25 +237,25 @@ class EpisodeListModel(gtk.ListStore):
         show_missing = False
         status_icon = None
         status_icon_to_build_from_file = False
-        tooltip = ''
+        tooltip = []
         view_show_undeleted = True
         view_show_downloaded = False
         view_show_unplayed = False
         icon_theme = gtk.icon_theme_get_default()
 
         if downloading is not None and downloading(episode):
-            tooltip = _('Downloading')
+            tooltip.append(_('Downloading'))
             status_icon = self.ICON_DOWNLOADING
             view_show_downloaded = True
             view_show_unplayed = True
         else:
             if episode.state == gpodder.STATE_DELETED:
-                tooltip = _('Deleted')
+                tooltip.append(_('Deleted'))
                 status_icon = self.ICON_DELETED
                 view_show_undeleted = False
             elif episode.state == gpodder.STATE_NORMAL and \
                     not episode.is_played:
-                tooltip = _('New episode')
+                tooltip.append(_('New episode'))
                 status_icon = self.ICON_NEW
                 view_show_downloaded = True
                 view_show_unplayed = True
@@ -322,9 +322,14 @@ class EpisodeListModel(gtk.ListStore):
                         tooltip.append(_('deletion prevented'))
 
                 if episode.total_time > 0 and episode.current_position:
-                    tooltip.append('%d%%' % (100.*float(episode.current_position)/float(episode.total_time)))
+                    tooltip.append('%d%%' % (100.*float(episode.current_position)/float(episode.total_time),))
 
-                tooltip = ', '.join(tooltip)
+        if episode.total_time:
+            total_time = util.format_time(episode.total_time)
+            if total_time:
+                tooltip.append(total_time)
+
+        tooltip = ', '.join(tooltip)
 
         if status_icon is not None:
             status_icon = self._get_tree_icon(status_icon, show_bullet, \

src/gpodder/model.py

@@ -28,6 +28,7 @@ from gpodder import util
 from gpodder import feedcore
 from gpodder import youtube
 from gpodder import corestats
+from gpodder import gstreamer
 
 from gpodder.liblogger import log
 
@@ -690,6 +691,13 @@ class PodcastEpisode(PodcastModelObject):
         episode.link = entry.get('link', '')
         episode.description = entry.get('summary', '')
 
+        try:
+            # Parse iTunes-specific podcast duration metadata
+            total_time = util.parse_time(entry.get('itunes_duration', ''))
+            episode.total_time = total_time
+        except:
+            pass
+
         # Fallback to subtitle if summary is not available0
         if not episode.description:
             episode.description = entry.get('subtitle', '')
@@ -804,7 +812,7 @@ class PodcastEpisode(PodcastModelObject):
         # Time attributes
         self.total_time = 0
         self.current_position = 0
-        self.current_position_updated = time.time()
+        self.current_position_updated = 0
 
     def get_is_locked(self):
         return self._is_locked
@@ -823,6 +831,22 @@ class PodcastEpisode(PodcastModelObject):
         self.state = gpodder.STATE_DOWNLOADED
         self.is_played = False
         self.length = os.path.getsize(filename)
+
+        if not self.total_time:
+            try:
+                length = gstreamer.get_track_length(filename)
+                if length is not None:
+                    length = int(length/1000)
+                    log('Detected media length: %d seconds', length, \
+                            sender=self)
+                    self.total_time = length
+                    self.db.save_episode(self)
+                    self.db.commit()
+                    return
+            except Exception, e:
+                log('Error while detecting media length: %s', str(e), \
+                        sender=self)
+
         self.db.save_downloaded_episode(self)
         self.db.commit()
 

src/gpodder/util.py

@@ -1039,8 +1039,55 @@ def bluetooth_send_file(filename):
     else:
         log('Cannot send file. Please install "bluetooth-sendto" or "gnome-obex-send".')
         return False
-        
-        
+
+
+def format_time(value):
+    """Format a seconds value to a string
+
+    >>> format_time(0)
+    '00:00'
+    >>> format_time(20)
+    '00:20'
+    >>> format_time(3600)
+    '01:00:00'
+    >>> format_time(10921)
+    '03:02:01'
+    """
+    dt = datetime.datetime.utcfromtimestamp(value)
+    if dt.hour == 0:
+        return dt.strftime('%M:%S')
+    else:
+        return dt.strftime('%H:%M:%S')
+
+
+def parse_time(value):
+    """Parse a time string into seconds
+    >>> parse_time('00:00')
+    0
+    >>> parse_time('00:00:00')
+    0
+    >>> parse_time('00:20')
+    20
+    >>> parse_time('00:00:20')
+    20
+    >>> parse_time('01:00:00')
+    3600
+    >>> parse_time('03:02:01')
+    10921
+    """
+    if not value:
+        raise ValueError('Invalid value: %s' % (str(value),))
+
+    for format in ('%H:%M:%S', '%M:%S'):
+        try:
+            t = time.strptime(value, format)
+            return (t.tm_hour * 60 + t.tm_min) * 60 + t.tm_sec
+        except ValueError, ve:
+            continue
+
+    return int(value)
+
+
 def format_seconds_to_hour_min_sec(seconds):
     """
     Take the number of seconds and format it into a