Sets the datetime pointed to by @value corresponding to the datetime of the
given field. Caller is responsible for making sure the field exists
and has the correct type.
On success @value will point to a reference of the datetime which
should be unreffed with gst_date_time_unref() when no longer needed
(note: this is inconsistent with e.g. gst_structure_get_string()
which doesn't return a copy of the string).
%TRUE if the value could be set correctly. If there was no field
with @fieldname or the existing field did not contain a data, this function
returns %FALSE.
Sets the datetime pointed to by @value corresponding to the datetime of the given field. Caller is responsible for making sure the field exists and has the correct type.
On success @value will point to a reference of the datetime which should be unreffed with gst_date_time_unref() when no longer needed (note: this is inconsistent with e.g. gst_structure_get_string() which doesn't return a copy of the string).