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By Juan A. Suarez. Grilo is a framework that helps developers to retrieve multimedia content from different sources, both local and online, using a single and common API to browse, search and finally get the results. Nowadays Grilo is used by different applications inside the GNOME project: Totem, Rygel, Rythmbox, and in new coming applications like gnome-music and gnome-photos (this one in a next version). The aim of this talk is to check the requirements these different applications have to access the content, and how Grilo helps to fulfil them. We will see also other use-cases that can be solved with Grilo, which for sure be helpful for other developments.
Citation preview
static void_g_digicam_manager_class_init (GDigicamManagerClass
*klass){
GObjectClass *object_class = (GObjectClass*) klass;
g_assert (G_DIGICAM_IS_MANAGER_CLASS (klass));
parent_class = g_type_class_peek_parent (klass);
g_type_class_add_private (klass, sizeof (GDigicamManagerPrivate));
/* Override virtual functions */ object_class->finalize = _g_digicam_manager_finalize;
/** * GDigicamManager::focus-done:
* @manager: the gdigicam manager
Juan A. Suárez [email protected]
Writing multimedia applications with Grilo
Opening
Sources
Sources
Grilo
● Framework focused on making discovery and browsing easy for application developers● A single, high-level API for all the sources
● Plugins● Provides access to multimedia content● Extendable
Grilo
SOURCESOURCESOURCE
SOURCESOURCEMEDIASOURCESOURCE
METADATAKEYS
crea
tes
contains
provides
YoutubeJamendoFlickrIMDB...
AudioVideoImage...
TitleArtistAlbum...
Totem
Totem
Requirements
● Define what we need● Type of content
– Any kind?– Only video? Music?
● Metadata keys– URL– Title– Thumbnail– ... 55 metadata keys
Content to show
● Ignore any source that does not provide Videos● In “browse” view, ignore any source that does
not support browsing● In “search” view, ignore any source that does
not support searching
Information to show
- Title- Author- Duration- Thumbnail- URL
- Title- Author- Duration- Thumbnail- URL
Browse Search
Invoke Grilo
- Title- Author- Duration- Thumbnail- URL
- Title- Author- Duration- Thumbnail- URL
Browse Search
Problems
● Two problems to solve● Source not handling some keys● Too much expensive to retrieve some keys
Totem
● Flags to control content retrieval● Normal: provides the known requested content
– GRL_RESOLVE_NORMAL● Fast only: provides the known requested content
that does not penalize the operation in terms of performance– GRL_RESOLVE_FAST_ONLY
● Full: provides the known requested content using all the available sources– GRL_RESOLVE_FULL
Reduce the problems
● Request content in chunks● Request fast only in first iteration● While current chunk is visible
● Ask for each visible media element the discarded keys (using full flag)
● URL key case: slow key and not shown in the UI● Request it when user wants to play
GNOME Music
GNOME MusicCover Art
GNOME Music
● Music defines its own structure
● Grilo's one is different● Does not have concept of “Artist” or “Album”
● They are “boxes”
● Needs to sort the results
GNOME Music
Approaches
● Request content from Tracker directly● Create Grilo Media elements to add missing information
(Cover Art)
● Instruct Grilo's Tracker plugin how to construct the medias
● Use query() function● Very specific to the plugin● In case of Tracker plugin, use SPARQL to make the query
– First column is the media to build– Use alias to map each SPARQL column to specific metadata keys
Closing
Other use-cases
● Application to upload audio/video content to web services● store() function
● Mediaplayer with auto-resume● “playback-interrupted-time” key● store_metadata() function
– Metadata Store source handles it
Show me a code
Resources
● Wiki● http://live.gnome.org/Grilo
● Source code● git://git.gnome.org/grilo● git://git.gnome.org/grilo-plugins
● IRC● #grilo at irc.gnome.org
● Mailing list● http://mail.gnome.org/mailman/listinfo/grilo-list
