mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2025-01-29 18:48:44 +00:00
Code Issues 1 Projects Releases Wiki Activity

pwg: remove confusing metadata example with 0.8 code

Browse source 
Fixes #534314.
This commit is contained in:
Tim-Philipp Müller 2010-05-02 19:43:55 +01:00
parent 77120a04a5
commit 62a37d79c9
1 changed files with 2 additions and 67 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

69
docs/pwg/advanced-tagging.xml
View file

@ -74,73 +74,8 @@
tag events downstream, either over all source pad or the pad specified.
</para>
<para>
The following example program will parse a file and parse the data as
metadata/tags rather than as actual content-data. It will parse each
line as <quote>name:value</quote>, where name is the type of metadata
(title, author, ...) and value is the metadata value. The
<function>_getline ()</function> is the same as the one given in
<xref linkend="section-reqpad-sometimes"/>.
</para>
<programlisting>
<![CDATA[
static void
gst_my_filter_task_func (GstElement *element)
{
GstMyFilter *filter = GST_MY_FILTER (element);
GstBuffer *buf;
GstTagList *taglist = gst_tag_list_new ();
/* get each line and parse as metadata */
while ((buf = gst_my_filter_getline (filter))) {
gchar *line = GST_BUFFER_DATA (buf), *colon_pos, *type = NULL;a
/* get the position of the ':' and go beyond it */
if (!(colon_pos = strchr (line, ':')))
goto next:
/* get the string before that as type of metadata */
type = g_strndup (line, colon_pos - line);
/* content is one character beyond the ':' */
colon_pos = &colon_pos[1];
if (*colon_pos == '\0')
goto next;
/* get the metadata category, it's value type, store it in that
* type and add it to the taglist. */
if (gst_tag_exists (type)) {
GValue from = { 0 }, to = { 0 };
GType to_type;
to_type = gst_tag_get_type (type);
g_value_init (&from, G_TYPE_STRING);
g_value_set_string (&from, colon_pos);
g_value_init (&to, to_type);
g_value_transform (&from, &to);
g_value_unset (&from);
gst_tag_list_add_values (taglist, GST_TAG_MERGE_APPEND,
type, &to, NULL);
g_value_unset (&to);
}
next:
g_free (type);
gst_buffer_unref (buf);
}
/* signal metadata */
gst_element_found_tags_for_pad (element, filter->srcpad, 0, taglist);
gst_tag_list_free (taglist);
/* send EOS */
gst_pad_send_event (filter->srcpad, GST_DATA (gst_event_new (GST_EVENT_EOS)));
gst_element_set_eos (element);
}
]]>
</programlisting>
<para>
We currently assume the core to already <emphasis>know</emphasis> the
mimetype (<function>gst_tag_exists ()</function>). You can add new tags
We currently require the core to know the GType of tags before they are
being used, so all tags must be registered first. You can add new tags
to the list of known tags using <function>gst_tag_register ()</function>.
If you think the tag will be useful in more cases than just your own
element, it might be a good idea to add it to <filename>gsttag.c</filename>