Package org.freedesktop.gstreamer.gst

Interface TagSetter

All Superinterfaces:

Proxy

All Known Implementing Classes:

TagSetter.TagSetter$Impl

@Generated("org.javagi.JavaGI")
public interface TagSetter
extends Proxy

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. gst_tag_setter_merge_tags() or gst_tag_setter_add_tags(). Also consider setting the GstTagMergeMode 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 State.PAUSED.

Elements implementing the GstTagSetter 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);
 GST_LOG_OBJECT (tagsetter, "event tags: %" GST_PTR_FORMAT, event_tags);
 GST_LOG_OBJECT (tagsetter, "set   tags: %" GST_PTR_FORMAT, application_tags);

 result = gst_tag_list_merge (application_tags, event_tags, merge_mode);

 GST_LOG_OBJECT (tagsetter, "final tags: %" GST_PTR_FORMAT, result);
 

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	TagSetter.TagSetter$Impl	The TagSetter$Impl type represents a native instance of the TagSetter interface.
static class	TagSetter.TagSetterInterface	GstTagSetterInterface interface.

Method Summary

Modifier and Type	Method	Description
default void	addTags(TagMergeMode mode, String tag, Object... varargs)	Adds the given tag / value pairs on the setter using the given merge mode.
default void	addTagValue(TagMergeMode mode, String tag, Value value)	Adds the given tag / GValue pair on the setter using the given merge mode.
default void	addTagValues(TagMergeMode mode, String tag, Object... varargs)	Adds the given tag / GValue pairs on the setter using the given merge mode.
default @Nullable TagList	getTagList()	Returns the current list of tags the setter uses.
default TagMergeMode	getTagMergeMode()	Queries the mode by which tags inside the setter are overwritten by tags from events
static @Nullable Type	getType()	Get the GType of the TagSetter class
default void	mergeTags(TagList list, TagMergeMode mode)	Merges the given list into the setter's list using the given mode.
default void	resetTags()	Reset the internal taglist.
default void	setTagMergeMode(TagMergeMode mode)	Sets the given merge mode that is used for adding tags from events to tags specified by this interface.

Methods inherited from interface org.javagi.base.Proxy

handle

Method Details

getType

static @Nullable Type getType()

Get the GType of the TagSetter class

Returns:

the GType

addTagValue

default void addTagValue(TagMergeMode mode,
 String tag,
 Value value)

Adds the given tag / GValue pair on the setter using the given merge mode.

Parameters:

mode - the mode to use

tag - tag to set

value - GValue to set for the tag

addTagValues

default void addTagValues(TagMergeMode mode,
 String tag,
 Object... varargs)

Adds the given tag / GValue pairs on the setter using the given merge mode. The list must be terminated with null.

Parameters:

mode - the mode to use

tag - tag to set

varargs - more tag / GValue pairs to set

addTags

default void addTags(TagMergeMode mode,
 String tag,
 Object... varargs)

Adds the given tag / value pairs on the setter using the given merge mode. The list must be terminated with null.

Parameters:

mode - the mode to use

tag - tag to set

varargs - more tag / value pairs to set

getTagList

default @Nullable TagList getTagList()

Returns the current list of tags the setter uses. The list should not be modified or freed.

This function is not thread-safe.

Returns:

a current snapshot of the taglist used in the setter or null if none is used.

getTagMergeMode

default TagMergeMode getTagMergeMode()

Queries the mode by which tags inside the setter are overwritten by tags from events

Returns:

the merge mode used inside the element.

mergeTags

default void mergeTags(TagList list,
 TagMergeMode mode)

Merges the given list into the setter's list using the given mode.

Parameters:

list - a tag list to merge from

mode - the mode to merge with

resetTags

default void resetTags()

Reset the internal taglist. Elements should call this from within the state-change handler.

setTagMergeMode

default void setTagMergeMode(TagMergeMode mode)

Sets the given merge mode that is used for adding tags from events to tags specified by this interface. The default is GST_TAG_MERGE_KEEP, which keeps the tags set with this interface and discards tags from events.

Parameters:

mode - The mode with which tags are added