upnp sd: Add support for Samsung devices' subtitles extensions

 * Request the sec:CaptionInfo and sec:CaptionInfoEx DIDL attributes
 * If one of the two caption attributes are present, build and add an
   input-slave option string which forces the subtitle demux
 * Add the sub-track-id option to input items with subtitles
   so the subtitles are immediately visible

modules/services_discovery/upnp.cpp

@@ -791,7 +791,8 @@ bool MediaServer::_fetchContents( Container* p_parent, int i_offset )
 
     IXML_Document* p_response = _browseAction( p_parent->getObjectID(),
                                       "BrowseDirectChildren",
-                                      "*", /* Filter */
+                                      "id,dc:title,res," /* Filter */
+                                      "sec:CaptionInfo,sec:CaptionInfoEx",
                                       psz_starting_index, /* StartingIndex */
                                       "0", /* RequestedCount */
                                       "" /* SortCriteria */
@@ -874,6 +875,13 @@ bool MediaServer::_fetchContents( Container* p_parent, int i_offset )
             if ( !title )
                 continue;
 
+            const char* psz_subtitles = xml_getChildElementValue( itemElement,
+                    "sec:CaptionInfo" );
+
+            if ( !psz_subtitles )
+                psz_subtitles = xml_getChildElementValue( itemElement,
+                        "sec:CaptionInfoEx" );
+
             /* Try to extract all resources in DIDL */
             IXML_NodeList* p_resource_list = ixmlDocument_getElementsByTagName( (IXML_Document*) itemElement, "res" );
             if ( p_resource_list )
@@ -897,7 +905,8 @@ bool MediaServer::_fetchContents( Container* p_parent, int i_offset )
                                                               i_minutes*60 +
                                                               i_seconds );
                     }
-                    Item* item = new Item( p_parent, objectID, title, psz_resource_url, i_duration );
+
+                    Item* item = new Item( p_parent, objectID, title, psz_resource_url, psz_subtitles, i_duration );
                     p_parent->addItem( item );
                 }
                 ixmlNodeList_free( p_resource_list );
@@ -975,14 +984,32 @@ void MediaServer::_buildPlaylist( Container* p_parent, input_item_node_t *p_inpu
     {
         Item* p_item = p_parent->getItem( i );
 
+        char **ppsz_opts = NULL;
+        char *psz_input_slave = p_item->buildInputSlaveOption();
+        if( psz_input_slave )
+        {
+            ppsz_opts = (char**)malloc( 2 * sizeof( char* ) );
+            ppsz_opts[0] = psz_input_slave;
+            ppsz_opts[1] = p_item->buildSubTrackIdOption();
+        }
+
         input_item_t* p_input_item = input_item_NewExt( p_item->getResource(),
-                                               p_item->getTitle(),
-                                               0,
-                                               NULL,
-                                               0,
-                                               p_item->getDuration() );
+                                           p_item->getTitle(),
+                                           psz_input_slave ? 2 : 0,
+                                           psz_input_slave ? ppsz_opts : NULL,
+                                           VLC_INPUT_OPTION_TRUSTED, /* XXX */
+                                           p_item->getDuration() );
 
         assert( p_input_item );
+        if( ppsz_opts )
+        {
+            free( ppsz_opts[0] );
+            free( ppsz_opts[1] );
+            free( ppsz_opts );
+
+            psz_input_slave = NULL;
+        }
+
         input_item_node_AppendItem( p_input_node, p_input_item );
         p_item->setInputItem( p_input_item );
     }
@@ -1107,14 +1134,17 @@ void MediaServerList::removeServer( const char* psz_udn )
 /*
  * Item class
  */
-Item::Item( Container* p_parent, const char* psz_object_id, const char* psz_title,
-           const char* psz_resource, mtime_t i_duration )
+Item::Item( Container* p_parent,
+        const char* psz_object_id, const char* psz_title,
+        const char* psz_resource, const char* psz_subtitles,
+        mtime_t i_duration )
 {
     _parent = p_parent;
 
     _objectID = psz_object_id;
     _title = psz_title;
     _resource = psz_resource;
+    _subtitles = psz_subtitles ? psz_subtitles : "";
     _duration = i_duration;
 
     _p_input_item = NULL;
@@ -1141,11 +1171,75 @@ const char* Item::getResource() const
     return _resource.c_str();
 }
 
+const char* Item::getSubtitles() const
+{
+    if( !_subtitles.size() )
+        return NULL;
+
+    return _subtitles.c_str();
+}
+
 mtime_t Item::getDuration() const
 {
     return _duration;
 }
 
+char* Item::buildInputSlaveOption() const
+{
+    const char *psz_subtitles    = getSubtitles();
+
+    const char *psz_scheme_delim = "://";
+    const char *psz_sub_opt_fmt  = ":input-slave=%s/%s://%s";
+    const char *psz_demux        = "subtitle";
+
+    char       *psz_uri_scheme   = NULL;
+    const char *psz_scheme_end   = NULL;
+    const char *psz_uri_location = NULL;
+    char       *psz_input_slave  = NULL;
+
+    size_t i_scheme_len;
+
+    if( !psz_subtitles )
+        return NULL;
+
+    psz_scheme_end = strstr( psz_subtitles, psz_scheme_delim );
+
+    /* subtitles not being an URI would make no sense */
+    if( !psz_scheme_end )
+        return NULL;
+
+    i_scheme_len   = psz_scheme_end - psz_subtitles;
+    psz_uri_scheme = (char*)malloc( i_scheme_len + 1 );
+
+    if( !psz_uri_scheme )
+        return NULL;
+
+    memcpy( psz_uri_scheme, psz_subtitles, i_scheme_len );
+    psz_uri_scheme[i_scheme_len] = '\0';
+
+    /* If the subtitles try to force a vlc demux,
+     * then something is very wrong */
+    if( strchr( psz_uri_scheme, '/' ) )
+    {
+        free( psz_uri_scheme );
+        return NULL;
+    }
+
+    psz_uri_location = psz_scheme_end + strlen( psz_scheme_delim );
+
+    if( -1 == asprintf( &psz_input_slave, psz_sub_opt_fmt,
+            psz_uri_scheme, psz_demux, psz_uri_location ) )
+        psz_input_slave = NULL;
+
+    free( psz_uri_scheme );
+    return psz_input_slave;
+}
+
+char* Item::buildSubTrackIdOption() const
+{
+    return strdup( ":sub-track-id=2" );
+}
+
 void Item::setInputItem( input_item_t* p_input_item )
 {
     if( _p_input_item == p_input_item )

modules/services_discovery/upnp.hpp

@@ -120,6 +120,7 @@ public:
     Item( Container*  parent,
           const char* objectID,
           const char* title,
+          const char* subtitles,
           const char* resource,
           mtime_t duration );
     ~Item();
@@ -127,6 +128,9 @@ public:
     const char* getObjectID() const;
     const char* getTitle() const;
     const char* getResource() const;
+    const char* getSubtitles() const;
+    char* buildInputSlaveOption() const;
+    char* buildSubTrackIdOption() const;
     mtime_t getDuration() const;
 
     void setInputItem( input_item_t* p_input_item );
@@ -139,6 +143,7 @@ private:
     std::string _objectID;
     std::string _title;
     std::string _resource;
+    std::string _subtitles;
     mtime_t _duration;
 };