Talk about how Totem and GNOME Music use Grilo to get access to multimedia content. Talk from GUADEC 2013.

1. 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 Romero
jasuarez@igalia.com
Writing multimedia
applications with Grilo

2. Opening

3. Sources

4. Sources

5. 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

6. Grilo
SOURCESOURCESOURCE
SOURCESOURCEMEDIA
SOURCESOURCE
METADATA
KEYS
creates
contains provides
Youtube
Jamendo
Flickr
IMDB
...
Audio
Video
Image
...
Title
Artist
Album
...

7. Totem

8. Totem

9. Requirements
● Define what we need
● Type of content
– Any kind?
– Only video? Music?
● Metadata keys
– URL
– Title
– Thumbnail
– ... 55 metadata keys

10. 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

11. Information to show
- Title
- Author
- Duration
- Thumbnail
- URL
- Title
- Author
- Duration
- Thumbnail
- URL
Browse Search

12. Invoke Grilo
- Title
- Author
- Duration
- Thumbnail
- URL
- Title
- Author
- Duration
- Thumbnail
- URL
Browse Search

13. Problems
● Two problems to solve
● Source not handling some keys
● Too much expensive to retrieve some keys

14. 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

15. 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

16. GNOME Music

17. GNOME Music
Cover Art

18. 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

19. GNOME Music

20. 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

21. Closing

22. 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

23. Show me a code

24. 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