Ok, I've started from the plugin template from cvs as suggested on plugin writer manual. All that I've done was to change the base class to gst_base_src, just to see if I can create my own plugin deriving it from base_src. Here's some snippet: .h #include <gst/base/gstbasesrc.h> G_BEGIN_DECLS /* #defines don't like whitespacey bits */ #define GST_TYPE_PLUGIN_TEMPLATE \   (gst_plugin_template_get_type())/*(gst_base_src_get_type())*/ #define GST_PLUGIN_TEMPLATE(obj) \   (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_PLUGIN_TEMPLATE,GstPluginTattile)) #define GST_PLUGIN_TEMPLATE_CLASS(klass) \   (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_PLUGIN_TEMPLATE,GstPluginTattileClass)) #define GST_IS_PLUGIN_TEMPLATE(obj) \   (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_PLUGIN_TEMPLATE)) #define GST_IS_PLUGIN_TEMPLATE_CLASS(klass) \   (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_PLUGIN_TEMPLATE)) typedef struct _GstMyPlugin GstMyPlugin ; typedef struct _GstMyPlugin Class GstMyPlugin Class; struct _GstMyPlugin {   GstBaseSrc element;   GstPad *srcpad;   gboolean silent; }; struct _GstMyPlugin Class {   GstBaseSrcClass parent_class; }; GType gst_plugin_template_get_type (void); G_END_DECLS #endif /* __GST_PLUGIN_TEMPLATE_H__ */ And .c : #include "gstplugin.h" GST_DEBUG_CATEGORY_STATIC (gst_plugin_template_debug); #define GST_CAT_DEFAULT gst_plugin_template_debug /* Filter signals and args */ enum {   /* FILL ME */   LAST_SIGNAL }; enum {   ARG_0,   ARG_SILENT }; static GstFlowReturn create (GstBaseSrc *src, guint64 offset, guint size,                          GstBuffer **buf); static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",     GST_PAD_SRC,     GST_PAD_ALWAYS,     GST_STATIC_CAPS ("ANY")     ); GST_BOILERPLATE (GstMyPlugin, gst_plugin_template, GstBaseSrc ,     GST_TYPE_BASE_SRC); static void gst_plugin_template_set_property (GObject * object, guint prop_id,     const GValue * value, GParamSpec * pspec); static void gst_plugin_template_get_property (GObject * object, guint prop_id,     GValue * value, GParamSpec * pspec); static gboolean gst_plugin_template_set_caps (GstPad * pad, GstCaps * caps); static GstFlowReturn gst_plugin_template_chain (GstPad * pad, GstBuffer * buf); ......... I'm omitting the implementation of these function because I haven't touched the plugin template from cvs, I've only erased all the references to the sink element since I'm trying to write a src plugin. Thank's. <div>2007/6/29, René Stadler <<a href="mailto:mail@renestadler.de">mail@renestadler.de</a>>:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Am Freitag, den 29.06.2007, 18:34 +0200 schrieb Riccardo Corona: > I've wrote the vmethod create() and set the type as GST_TYPE_BASE_SRC, > but now gst-inspect give me this  error : > CRITICAL **: file E:\devel-cvs\src\gstreamer\gst\gstelementfactory.c: > line 266: assertion `g_type_is_a (type, GST_TYPE_ELEMENT)' >  failed > This indicates a problem with the setup of your element.  Could be anything.  No one can help you without seeing your code. <snipped away mess of previous mails> -- Regards,   René Stadler </blockquote></div> -- Riccardo Corona