gst-libs/gst/basecamerabinsrc/gstcamerabinpreview.c - mtk-gst-plugins-bad - Git at Google

 /*
  * GStreamer
  * Copyright (C) 2008 Nokia Corporation <multimedia@maemo.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 /**
  * SECTION:camerabingeneral
  * @short_description: helper functions for #GstCameraBin and it's modules
  *
  * Common helper functions for #GstCameraBin, #GstCameraBinImage and
  * #GstCameraBinVideo.
  *
  */
 #include <gst/app/gstappsrc.h>
 #include <gst/app/gstappsink.h>
 #include <gst/glib-compat-private.h>
 #include "gstcamerabinpreview.h"
 #include "gstbasecamerasrc.h"

 GST_DEBUG_CATEGORY_EXTERN (base_camera_src_debug);
 #define GST_CAT_DEFAULT base_camera_src_debug

 static void _gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData *
     preview, GstCaps * caps);

 static gboolean
 bus_callback (GstBus * bus, GstMessage * message, gpointer user_data)
 {
   switch (GST_MESSAGE_TYPE (message)) {
     case GST_MESSAGE_ERROR:{
       GError *err;
       GstCameraBinPreviewPipelineData *data;

       data = user_data;

       gst_message_parse_error (message, &err, NULL);
       GST_WARNING ("Error from preview pipeline: %s", err->message);
       g_error_free (err);

       /* TODO Not sure if we should post an Error or Warning here */
       GST_ELEMENT_ERROR (data, CORE, FAILED,
           ("fatal error in preview pipeline, disposing the pipeline"), (NULL));

       /* Possible error situations:
        * 1) cond_wait pending. prevent deadlock by signalling the cond
        * 2) preview_pipeline_post called with new buffer to handle. returns
        *    because data->pipeline is set to null
        * 3) new preview caps incoming. returns because data->pipeline is null
        */

       if (data->pipeline) {
         gst_element_set_state (data->pipeline, GST_STATE_NULL);
         gst_object_unref (data->pipeline);
         data->pipeline = NULL;
       }

       g_cond_signal (&data->processing_cond);

       break;
     }
     default:
       break;
   }
   return TRUE;
 }

 static GstFlowReturn
 gst_camerabin_preview_pipeline_new_sample (GstAppSink * appsink,
     gpointer user_data)
 {
   GstSample *sample;
   GstStructure *s;
   GstMessage *msg;
   GstCameraBinPreviewPipelineData *data;

   data = user_data;

   sample = gst_app_sink_pull_sample (appsink);
   s = gst_structure_new (GST_BASE_CAMERA_SRC_PREVIEW_MESSAGE_NAME,
       "sample", GST_TYPE_SAMPLE, sample, NULL);
   gst_sample_unref (sample);
   msg = gst_message_new_element (GST_OBJECT (data->element), s);

   GST_DEBUG_OBJECT (data->element, "sending message with preview image");
   if (gst_element_post_message (data->element, msg) == FALSE) {
     GST_WARNING_OBJECT (data->element,
         "This element has no bus, therefore no message sent!");
   }

   g_mutex_lock (&data->processing_lock);

   data->processing--;
   if (data->processing == 0)
     g_cond_signal (&data->processing_cond);

   g_mutex_unlock (&data->processing_lock);

   return GST_FLOW_OK;
 }

 /**
  * gst_camerabin_create_preview_pipeline:
  * @element: Owner of this pipeline
  * @filter: Custom filter to process preview data (an extra ref is taken)
  *
  * Creates a new previewing pipeline that can receive buffers
  * to be posted as camerabin preview messages for @element
  *
  * Returns: The newly created #GstCameraBinPreviewPipelineData
  */
 GstCameraBinPreviewPipelineData *
 gst_camerabin_create_preview_pipeline (GstElement * element,
     GstElement * filter)
 {
   GstCameraBinPreviewPipelineData *data;
   GstElement *csp;
   GstElement *vscale;
   gboolean added = FALSE;
   gboolean linkfail = FALSE;
   GstBus *bus;
   GstAppSinkCallbacks callbacks = { 0, };

   data = g_new0 (GstCameraBinPreviewPipelineData, 1);

   data->pipeline = gst_pipeline_new ("preview-pipeline");
   data->appsrc = gst_element_factory_make ("appsrc", "preview-appsrc");
   data->appsink = gst_element_factory_make ("appsink", "preview-appsink");
   csp = gst_element_factory_make ("videoconvert", "preview-vconv");
   vscale = gst_element_factory_make ("videoscale", "preview-vscale");

   if (!data->appsrc || !data->appsink || !csp || !vscale) {
     goto error;
   }

   g_object_set (data->appsrc, "emit-signals", FALSE, NULL);
   g_object_set (data->appsink, "sync", FALSE, "enable-last-sample",
       FALSE, NULL);

   gst_bin_add_many (GST_BIN (data->pipeline), data->appsrc,
       data->appsink, csp, vscale, NULL);
   if (filter)
     gst_bin_add (GST_BIN (data->pipeline), gst_object_ref (filter));
   added = TRUE;

   if (filter) {
     linkfail |=
         GST_PAD_LINK_FAILED (gst_element_link_pads_full (data->appsrc, "src",
             filter, NULL, GST_PAD_LINK_CHECK_NOTHING));
     linkfail |=
         GST_PAD_LINK_FAILED (gst_element_link_pads_full (filter, NULL,
             vscale, "sink", GST_PAD_LINK_CHECK_CAPS));
   } else {
     linkfail |=
         GST_PAD_LINK_FAILED (gst_element_link_pads_full (data->appsrc, "src",
             vscale, "sink", GST_PAD_LINK_CHECK_NOTHING));
   }

   linkfail |=
       GST_PAD_LINK_FAILED (gst_element_link_pads_full (vscale, "src", csp,
           "sink", GST_PAD_LINK_CHECK_NOTHING));
   linkfail |=
       GST_PAD_LINK_FAILED (gst_element_link_pads_full (csp, "src",
           data->appsink, "sink", GST_PAD_LINK_CHECK_NOTHING));

   if (linkfail) {
     GST_WARNING ("Failed to link preview pipeline elements");
     goto error;
   }

   callbacks.new_sample = gst_camerabin_preview_pipeline_new_sample;
   gst_app_sink_set_callbacks ((GstAppSink *) data->appsink, &callbacks, data,
       NULL);

   bus = gst_pipeline_get_bus (GST_PIPELINE (data->pipeline));
   gst_bus_add_watch (bus, bus_callback, data);
   gst_object_unref (bus);

   g_object_set (data->appsink, "sync", FALSE, NULL);

   data->element = element;
   data->filter = filter;
   data->vscale = vscale;

   g_mutex_init (&data->processing_lock);
   g_cond_init (&data->processing_cond);

   data->pending_preview_caps = NULL;
   data->processing = 0;

   return data;
 error:
   GST_WARNING ("Failed to create camerabin's preview pipeline");
   if (!added) {
     if (csp)
       gst_object_unref (csp);
     if (vscale)
       gst_object_unref (vscale);
     if (data->appsrc)
       gst_object_unref (data->appsrc);
     if (data->appsink)
       gst_object_unref (data->appsink);
   }
   gst_camerabin_destroy_preview_pipeline (data);
   return NULL;
 }

 /**
  * gst_camerabin_destroy_preview_pipeline:
  * @preview: the #GstCameraBinPreviewPipelineData
  *
  * Frees a #GstCameraBinPreviewPipelineData
  */
 void
 gst_camerabin_destroy_preview_pipeline (GstCameraBinPreviewPipelineData *
     preview)
 {
   g_return_if_fail (preview != NULL);

   g_mutex_clear (&preview->processing_lock);
   g_cond_clear (&preview->processing_cond);

   if (preview->pipeline) {
     GstBus *bus;

     gst_element_set_state (preview->pipeline, GST_STATE_NULL);

     bus = gst_pipeline_get_bus (GST_PIPELINE (preview->pipeline));
     gst_bus_remove_watch (bus);
     gst_object_unref (bus);

     gst_object_unref (preview->pipeline);
   }
   g_free (preview);
 }

 /**
  * gst_camerabin_preview_pipeline_post:
  * @preview: the #GstCameraBinPreviewPipelineData
  * @sample: the sample to be posted as a preview
  *
  * Converts the @sample to the desired format and posts the preview
  * message to the bus.
  *
  * Returns: %TRUE on success
  */
 gboolean
 gst_camerabin_preview_pipeline_post (GstCameraBinPreviewPipelineData * preview,
     GstSample * sample)
 {
   g_return_val_if_fail (preview != NULL, FALSE);
   g_return_val_if_fail (preview->pipeline != NULL, FALSE);
   g_return_val_if_fail (sample, FALSE);

   g_mutex_lock (&preview->processing_lock);
   g_return_val_if_fail (preview->pipeline != NULL, FALSE);

   if (preview->pending_preview_caps) {
     if (preview->processing > 0) {
       g_cond_wait (&preview->processing_cond, &preview->processing_lock);
     }
     _gst_camerabin_preview_set_caps (preview, preview->pending_preview_caps);
     gst_caps_replace (&preview->pending_preview_caps, NULL);
   }

   preview->processing++;

   g_object_set (preview->appsrc, "caps", gst_sample_get_caps (sample), NULL);
   gst_app_src_push_buffer ((GstAppSrc *) preview->appsrc,
       gst_buffer_ref (gst_sample_get_buffer (sample)));

   g_mutex_unlock (&preview->processing_lock);

   return TRUE;
 }

 static void
 _gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData * preview,
     GstCaps * caps)
 {
   GstState state, pending;
   GstStateChangeReturn ret;

   g_return_if_fail (preview != NULL);
   g_return_if_fail (preview->pipeline != NULL);

   ret = gst_element_get_state (preview->pipeline, &state, &pending, 0);
   if (ret == GST_STATE_CHANGE_FAILURE) {
     /* make it try again */
     state = GST_STATE_PLAYING;
     pending = GST_STATE_VOID_PENDING;
   }
   gst_element_set_state (preview->pipeline, GST_STATE_NULL);
   g_object_set (preview->appsink, "caps", caps, NULL);
   if (pending != GST_STATE_VOID_PENDING)
     state = pending;
   gst_element_set_state (preview->pipeline, state);
 }

 /**
  * gst_camerabin_preview_set_caps:
  * @preview: the #GstCameraBinPreviewPipelineData
  * @caps: the #GstCaps to be set (a new ref will be taken)
  *
  * The caps that preview buffers should have when posted
  * on the bus
  */
 void
 gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData * preview,
     GstCaps * caps)
 {
   g_return_if_fail (preview != NULL);

   g_mutex_lock (&preview->processing_lock);

   if (preview->processing == 0) {
     _gst_camerabin_preview_set_caps (preview, caps);
   } else {
     GST_DEBUG ("Preview pipeline busy, storing new caps as pending");
     gst_caps_replace (&preview->pending_preview_caps, caps);
   }
   g_mutex_unlock (&preview->processing_lock);
 }

 /**
  * gst_camerabin_preview_set_filter:
  * @preview: the #GstCameraBinPreviewPipelineData
  * @filter: Custom filter to process preview data (an extra ref is taken)
  *
  * Set the filter element into preview pipeline.
  *
  * Returns: %TRUE on success
  */
 gboolean
 gst_camerabin_preview_set_filter (GstCameraBinPreviewPipelineData * preview,
     GstElement * filter)
 {
   gboolean ret = TRUE;
   GstState current;

   g_return_val_if_fail (preview != NULL, FALSE);

   GST_DEBUG ("Preview pipeline setting new filter %p", filter);

   g_mutex_lock (&preview->processing_lock);

   gst_element_get_state (preview->pipeline, &current, NULL, 0);

   if (preview->processing == 0 && current == GST_STATE_NULL) {
     gboolean linkfail = FALSE;

     if (preview->filter) {
       /* Unlink and remove old filter */
       gst_element_unlink (preview->appsrc, preview->filter);
       gst_element_unlink (preview->filter, preview->vscale);
       gst_bin_remove (GST_BIN (preview->pipeline), preview->filter);
     } else {
       /* Make room for filter by breaking the link between appsrc and vcale */
       gst_element_unlink (preview->appsrc, preview->vscale);
     }

     if (filter) {
       /* Add and link the new filter between appsrc and vscale */
       gst_bin_add (GST_BIN (preview->pipeline), gst_object_ref (filter));

       linkfail |=
           GST_PAD_LINK_FAILED (gst_element_link_pads_full (preview->appsrc,
               "src", filter, NULL, GST_PAD_LINK_CHECK_NOTHING));

       linkfail |=
           GST_PAD_LINK_FAILED (gst_element_link_pads_full (filter, NULL,
               preview->vscale, "sink", GST_PAD_LINK_CHECK_CAPS));
     } else {
       /* No filter was given. Just link the appsrc to vscale directly */
       linkfail |=
           GST_PAD_LINK_FAILED (gst_element_link_pads_full (preview->appsrc,
               "src", preview->vscale, "sink", GST_PAD_LINK_CHECK_NOTHING));
     }

     if (linkfail) {
       GST_WARNING ("Linking the filter to pipeline failed");
       ret = FALSE;
     } else {
       GST_DEBUG ("Linking the filter to pipeline successful");
       preview->filter = filter;
     }
   } else {
     GST_WARNING ("Cannot change filter when pipeline is running");
     ret = FALSE;
   }
   g_mutex_unlock (&preview->processing_lock);

   return ret;
 }
	/*
	* GStreamer
	* Copyright (C) 2008 Nokia Corporation <multimedia@maemo.org>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public
	* License along with this library; if not, write to the
	* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	/**
	* SECTION:camerabingeneral
	* @short_description: helper functions for #GstCameraBin and it's modules
	*
	* Common helper functions for #GstCameraBin, #GstCameraBinImage and
	* #GstCameraBinVideo.
	*
	*/
	#include <gst/app/gstappsrc.h>
	#include <gst/app/gstappsink.h>
	#include <gst/glib-compat-private.h>
	#include "gstcamerabinpreview.h"
	#include "gstbasecamerasrc.h"

	GST_DEBUG_CATEGORY_EXTERN (base_camera_src_debug);
	#define GST_CAT_DEFAULT base_camera_src_debug

	static void _gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData *
	preview, GstCaps * caps);

	static gboolean
	bus_callback (GstBus * bus, GstMessage * message, gpointer user_data)
	{
	switch (GST_MESSAGE_TYPE (message)) {
	case GST_MESSAGE_ERROR:{
	GError *err;
	GstCameraBinPreviewPipelineData *data;

	data = user_data;

	gst_message_parse_error (message, &err, NULL);
	GST_WARNING ("Error from preview pipeline: %s", err->message);
	g_error_free (err);

	/* TODO Not sure if we should post an Error or Warning here */
	GST_ELEMENT_ERROR (data, CORE, FAILED,
	("fatal error in preview pipeline, disposing the pipeline"), (NULL));

	/* Possible error situations:
	* 1) cond_wait pending. prevent deadlock by signalling the cond
	* 2) preview_pipeline_post called with new buffer to handle. returns
	* because data->pipeline is set to null
	* 3) new preview caps incoming. returns because data->pipeline is null
	*/

	if (data->pipeline) {
	gst_element_set_state (data->pipeline, GST_STATE_NULL);
	gst_object_unref (data->pipeline);
	data->pipeline = NULL;
	}

	g_cond_signal (&data->processing_cond);

	break;
	}
	default:
	break;
	}
	return TRUE;
	}

	static GstFlowReturn
	gst_camerabin_preview_pipeline_new_sample (GstAppSink * appsink,
	gpointer user_data)
	{
	GstSample *sample;
	GstStructure *s;
	GstMessage *msg;
	GstCameraBinPreviewPipelineData *data;

	data = user_data;

	sample = gst_app_sink_pull_sample (appsink);
	s = gst_structure_new (GST_BASE_CAMERA_SRC_PREVIEW_MESSAGE_NAME,
	"sample", GST_TYPE_SAMPLE, sample, NULL);
	gst_sample_unref (sample);
	msg = gst_message_new_element (GST_OBJECT (data->element), s);

	GST_DEBUG_OBJECT (data->element, "sending message with preview image");
	if (gst_element_post_message (data->element, msg) == FALSE) {
	GST_WARNING_OBJECT (data->element,
	"This element has no bus, therefore no message sent!");
	}

	g_mutex_lock (&data->processing_lock);

	data->processing--;
	if (data->processing == 0)
	g_cond_signal (&data->processing_cond);

	g_mutex_unlock (&data->processing_lock);

	return GST_FLOW_OK;
	}

	/**
	* gst_camerabin_create_preview_pipeline:
	* @element: Owner of this pipeline
	* @filter: Custom filter to process preview data (an extra ref is taken)
	*
	* Creates a new previewing pipeline that can receive buffers
	* to be posted as camerabin preview messages for @element
	*
	* Returns: The newly created #GstCameraBinPreviewPipelineData
	*/
	GstCameraBinPreviewPipelineData *
	gst_camerabin_create_preview_pipeline (GstElement * element,
	GstElement * filter)
	{
	GstCameraBinPreviewPipelineData *data;
	GstElement *csp;
	GstElement *vscale;
	gboolean added = FALSE;
	gboolean linkfail = FALSE;
	GstBus *bus;
	GstAppSinkCallbacks callbacks = { 0, };

	data = g_new0 (GstCameraBinPreviewPipelineData, 1);

	data->pipeline = gst_pipeline_new ("preview-pipeline");
	data->appsrc = gst_element_factory_make ("appsrc", "preview-appsrc");
	data->appsink = gst_element_factory_make ("appsink", "preview-appsink");
	csp = gst_element_factory_make ("videoconvert", "preview-vconv");
	vscale = gst_element_factory_make ("videoscale", "preview-vscale");

	if (!data->appsrc \|\| !data->appsink \|\| !csp \|\| !vscale) {
	goto error;
	}

	g_object_set (data->appsrc, "emit-signals", FALSE, NULL);
	g_object_set (data->appsink, "sync", FALSE, "enable-last-sample",
	FALSE, NULL);

	gst_bin_add_many (GST_BIN (data->pipeline), data->appsrc,
	data->appsink, csp, vscale, NULL);
	if (filter)
	gst_bin_add (GST_BIN (data->pipeline), gst_object_ref (filter));
	added = TRUE;

	if (filter) {
	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (data->appsrc, "src",
	filter, NULL, GST_PAD_LINK_CHECK_NOTHING));
	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (filter, NULL,
	vscale, "sink", GST_PAD_LINK_CHECK_CAPS));
	} else {
	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (data->appsrc, "src",
	vscale, "sink", GST_PAD_LINK_CHECK_NOTHING));
	}

	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (vscale, "src", csp,
	"sink", GST_PAD_LINK_CHECK_NOTHING));
	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (csp, "src",
	data->appsink, "sink", GST_PAD_LINK_CHECK_NOTHING));

	if (linkfail) {
	GST_WARNING ("Failed to link preview pipeline elements");
	goto error;
	}

	callbacks.new_sample = gst_camerabin_preview_pipeline_new_sample;
	gst_app_sink_set_callbacks ((GstAppSink *) data->appsink, &callbacks, data,
	NULL);

	bus = gst_pipeline_get_bus (GST_PIPELINE (data->pipeline));
	gst_bus_add_watch (bus, bus_callback, data);
	gst_object_unref (bus);

	g_object_set (data->appsink, "sync", FALSE, NULL);

	data->element = element;
	data->filter = filter;
	data->vscale = vscale;

	g_mutex_init (&data->processing_lock);
	g_cond_init (&data->processing_cond);

	data->pending_preview_caps = NULL;
	data->processing = 0;

	return data;
	error:
	GST_WARNING ("Failed to create camerabin's preview pipeline");
	if (!added) {
	if (csp)
	gst_object_unref (csp);
	if (vscale)
	gst_object_unref (vscale);
	if (data->appsrc)
	gst_object_unref (data->appsrc);
	if (data->appsink)
	gst_object_unref (data->appsink);
	}
	gst_camerabin_destroy_preview_pipeline (data);
	return NULL;
	}

	/**
	* gst_camerabin_destroy_preview_pipeline:
	* @preview: the #GstCameraBinPreviewPipelineData
	*
	* Frees a #GstCameraBinPreviewPipelineData
	*/
	void
	gst_camerabin_destroy_preview_pipeline (GstCameraBinPreviewPipelineData *
	preview)
	{
	g_return_if_fail (preview != NULL);

	g_mutex_clear (&preview->processing_lock);
	g_cond_clear (&preview->processing_cond);

	if (preview->pipeline) {
	GstBus *bus;

	gst_element_set_state (preview->pipeline, GST_STATE_NULL);

	bus = gst_pipeline_get_bus (GST_PIPELINE (preview->pipeline));
	gst_bus_remove_watch (bus);
	gst_object_unref (bus);

	gst_object_unref (preview->pipeline);
	}
	g_free (preview);
	}

	/**
	* gst_camerabin_preview_pipeline_post:
	* @preview: the #GstCameraBinPreviewPipelineData
	* @sample: the sample to be posted as a preview
	*
	* Converts the @sample to the desired format and posts the preview
	* message to the bus.
	*
	* Returns: %TRUE on success
	*/
	gboolean
	gst_camerabin_preview_pipeline_post (GstCameraBinPreviewPipelineData * preview,
	GstSample * sample)
	{
	g_return_val_if_fail (preview != NULL, FALSE);
	g_return_val_if_fail (preview->pipeline != NULL, FALSE);
	g_return_val_if_fail (sample, FALSE);

	g_mutex_lock (&preview->processing_lock);
	g_return_val_if_fail (preview->pipeline != NULL, FALSE);

	if (preview->pending_preview_caps) {
	if (preview->processing > 0) {
	g_cond_wait (&preview->processing_cond, &preview->processing_lock);
	}
	_gst_camerabin_preview_set_caps (preview, preview->pending_preview_caps);
	gst_caps_replace (&preview->pending_preview_caps, NULL);
	}

	preview->processing++;

	g_object_set (preview->appsrc, "caps", gst_sample_get_caps (sample), NULL);
	gst_app_src_push_buffer ((GstAppSrc *) preview->appsrc,
	gst_buffer_ref (gst_sample_get_buffer (sample)));

	g_mutex_unlock (&preview->processing_lock);

	return TRUE;
	}

	static void
	_gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData * preview,
	GstCaps * caps)
	{
	GstState state, pending;
	GstStateChangeReturn ret;

	g_return_if_fail (preview != NULL);
	g_return_if_fail (preview->pipeline != NULL);

	ret = gst_element_get_state (preview->pipeline, &state, &pending, 0);
	if (ret == GST_STATE_CHANGE_FAILURE) {
	/* make it try again */
	state = GST_STATE_PLAYING;
	pending = GST_STATE_VOID_PENDING;
	}
	gst_element_set_state (preview->pipeline, GST_STATE_NULL);
	g_object_set (preview->appsink, "caps", caps, NULL);
	if (pending != GST_STATE_VOID_PENDING)
	state = pending;
	gst_element_set_state (preview->pipeline, state);
	}

	/**
	* gst_camerabin_preview_set_caps:
	* @preview: the #GstCameraBinPreviewPipelineData
	* @caps: the #GstCaps to be set (a new ref will be taken)
	*
	* The caps that preview buffers should have when posted
	* on the bus
	*/
	void
	gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData * preview,
	GstCaps * caps)
	{
	g_return_if_fail (preview != NULL);

	g_mutex_lock (&preview->processing_lock);

	if (preview->processing == 0) {
	_gst_camerabin_preview_set_caps (preview, caps);
	} else {
	GST_DEBUG ("Preview pipeline busy, storing new caps as pending");
	gst_caps_replace (&preview->pending_preview_caps, caps);
	}
	g_mutex_unlock (&preview->processing_lock);
	}

	/**
	* gst_camerabin_preview_set_filter:
	* @preview: the #GstCameraBinPreviewPipelineData
	* @filter: Custom filter to process preview data (an extra ref is taken)
	*
	* Set the filter element into preview pipeline.
	*
	* Returns: %TRUE on success
	*/
	gboolean
	gst_camerabin_preview_set_filter (GstCameraBinPreviewPipelineData * preview,
	GstElement * filter)
	{
	gboolean ret = TRUE;
	GstState current;

	g_return_val_if_fail (preview != NULL, FALSE);

	GST_DEBUG ("Preview pipeline setting new filter %p", filter);

	g_mutex_lock (&preview->processing_lock);

	gst_element_get_state (preview->pipeline, &current, NULL, 0);

	if (preview->processing == 0 && current == GST_STATE_NULL) {
	gboolean linkfail = FALSE;

	if (preview->filter) {
	/* Unlink and remove old filter */
	gst_element_unlink (preview->appsrc, preview->filter);
	gst_element_unlink (preview->filter, preview->vscale);
	gst_bin_remove (GST_BIN (preview->pipeline), preview->filter);
	} else {
	/* Make room for filter by breaking the link between appsrc and vcale */
	gst_element_unlink (preview->appsrc, preview->vscale);
	}

	if (filter) {
	/* Add and link the new filter between appsrc and vscale */
	gst_bin_add (GST_BIN (preview->pipeline), gst_object_ref (filter));

	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (preview->appsrc,
	"src", filter, NULL, GST_PAD_LINK_CHECK_NOTHING));

	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (filter, NULL,
	preview->vscale, "sink", GST_PAD_LINK_CHECK_CAPS));
	} else {
	/* No filter was given. Just link the appsrc to vscale directly */
	linkfail \|=
	GST_PAD_LINK_FAILED (gst_element_link_pads_full (preview->appsrc,
	"src", preview->vscale, "sink", GST_PAD_LINK_CHECK_NOTHING));
	}

	if (linkfail) {
	GST_WARNING ("Linking the filter to pipeline failed");
	ret = FALSE;
	} else {
	GST_DEBUG ("Linking the filter to pipeline successful");
	preview->filter = filter;
	}
	} else {
	GST_WARNING ("Cannot change filter when pipeline is running");
	ret = FALSE;
	}
	g_mutex_unlock (&preview->processing_lock);

	return ret;
	}