TagSetter

Object Hierarchy:

Description:

public interface TagSetter : Element

Element interface that allows setting of media metadata. Elements that support changing a stream's metadata will implement this interface. Examples of such elements are 'vorbisenc', 'theoraenc' and 'id3v2mux'. If you just want to retrieve metadata in your application then all you need to do is watch for tag messages on your pipeline's bus. This interface is only for setting metadata, not for extracting it. To set tags from the application, find tagsetter elements and set tags using e.g. merge_tags or add_tags . Also consider setting the TagMergeMode that is used for tag events that arrive at the tagsetter element (default mode is to keep existing tags). The application should do that before the element goes to PAUSED. Elements implementing the TagSetter interface often have to merge any tags received from upstream and the tags set by the application via the interface. This can be done like this:


GstTagMergeMode merge_mode;
const GstTagList *application_tags;
const GstTagList *event_tags;
GstTagSetter *tagsetter;
GstTagList *result;
tagsetter = GST_TAG_SETTER (element);
merge_mode = gst_tag_setter_get_tag_merge_mode (tagsetter);
application_tags = gst_tag_setter_get_tag_list (tagsetter);
event_tags = (const GstTagList *) element->event_tags;
GST_LOG_OBJECT (tagsetter, "merging tags, merge mode = %d", merge_mode);
result = gst_tag_list_merge (application_tags, event_tags, merge_mode);

Last reviewed on 2006-05-18 (0.10.6)

Namespace: Gst

Package: gstreamer-0.10

Content:

Methods:

public void add_tag_valist (TagMergeMode mode, string tag, void* var_args)
Adds the given tag / value pairs on the setter using the given merge mode. The list must be terminated with NULL.
public void add_tag_valist_values (TagMergeMode mode, string tag, void* var_args)
Adds the given tag / GValue pairs on the setter using the given merge mode. The list must be terminated with NULL.
public void add_tag_value (TagMergeMode mode, string tag, Value value)
Adds the given tag / GValue pair on the setter using the given merge mode.
public void add_tag_values (TagMergeMode mode, string tag, ...)
Adds the given tag / GValue pairs on the setter using the given merge mode. The list must be terminated with NULL.
public void add_tags (TagMergeMode mode, string tag, ...)
Adds the given tag / value pairs on the setter using the given merge mode. The list must be terminated with NULL.
public unowned TagList get_tag_list ()
Returns the current list of tags the setter uses. The list should not be modified or freed. This function is not thread-safe. setter or NULL if none is used.
public TagMergeMode get_tag_merge_mode ()
Queries the mode by which tags inside the setter are overwritten by tags from events
public void merge_tags (TagList list, TagMergeMode mode)
Merges the given list into the setter's list using the given mode.
public void reset_tags ()
Reset the internal taglist. Elements should call this from within the state-change handler.
public void set_tag_merge_mode (TagMergeMode mode)
Sets the given merge mode that is used for adding tags from events to tags specified by this interface. The default is KEEP, which keeps the tags set with this interface and discards tags from events.