gstreamer/gst/debugutils/gstcompare.c
2014-04-09 15:21:20 +01:00

699 lines
20 KiB
C

/* GStreamer Element
*
* Copyright 2011 Collabora Ltd.
* @author: Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
* Copyright 2011 Nokia Corp.
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <gst/gst.h>
#include <gst/base/gstcollectpads.h>
#include <gst/video/video.h>
#include "gstcompare.h"
GST_DEBUG_CATEGORY_STATIC (compare_debug);
#define GST_CAT_DEFAULT compare_debug
static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate check_sink_factory =
GST_STATIC_PAD_TEMPLATE ("check",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
enum GstCompareMethod
{
GST_COMPARE_METHOD_MEM,
GST_COMPARE_METHOD_MAX,
GST_COMPARE_METHOD_SSIM
};
#define GST_COMPARE_METHOD_TYPE (gst_compare_method_get_type())
static GType
gst_compare_method_get_type (void)
{
static GType method_type = 0;
static const GEnumValue method_types[] = {
{GST_COMPARE_METHOD_MEM, "Memory", "mem"},
{GST_COMPARE_METHOD_MAX, "Maximum metric", "max"},
{GST_COMPARE_METHOD_SSIM, "SSIM (raw video)", "ssim"},
{0, NULL, NULL}
};
if (!method_type) {
method_type = g_enum_register_static ("GstCompareMethod", method_types);
}
return method_type;
}
/* Filter signals and args */
enum
{
/* FILL ME */
LAST_SIGNAL
};
enum
{
PROP_0,
PROP_META,
PROP_OFFSET_TS,
PROP_METHOD,
PROP_THRESHOLD,
PROP_UPPER,
PROP_LAST
};
#define DEFAULT_META GST_BUFFER_COPY_ALL
#define DEFAULT_OFFSET_TS FALSE
#define DEFAULT_METHOD GST_COMPARE_METHOD_MEM
#define DEFAULT_THRESHOLD 0
#define DEFAULT_UPPER TRUE
static void gst_compare_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec);
static void gst_compare_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec);
static void gst_compare_reset (GstCompare * overlay);
static gboolean gst_compare_query (GstPad * pad, GstObject * parent,
GstQuery * query);
static GstFlowReturn gst_compare_collect_pads (GstCollectPads * cpads,
GstCompare * comp);
static GstStateChangeReturn gst_compare_change_state (GstElement * element,
GstStateChange transition);
#define gst_compare_parent_class parent_class
G_DEFINE_TYPE (GstCompare, gst_compare, GST_TYPE_ELEMENT);
static void
gst_compare_finalize (GObject * object)
{
GstCompare *comp = GST_COMPARE (object);
gst_object_unref (comp->cpads);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_compare_class_init (GstCompareClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
GST_DEBUG_CATEGORY_INIT (compare_debug, "compare", 0, "Compare buffers");
gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_compare_change_state);
gobject_class->set_property = gst_compare_set_property;
gobject_class->get_property = gst_compare_get_property;
gobject_class->finalize = gst_compare_finalize;
g_object_class_install_property (gobject_class, PROP_META,
g_param_spec_flags ("meta", "Compare Meta",
"Indicates which metadata should be compared",
gst_buffer_copy_flags_get_type (), DEFAULT_META,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_OFFSET_TS,
g_param_spec_boolean ("offset-ts", "Offsets Timestamps",
"Consider OFFSET and OFFSET_END part of timestamp metadata",
DEFAULT_OFFSET_TS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_METHOD,
g_param_spec_enum ("method", "Content Compare Method",
"Method to compare buffer content",
GST_COMPARE_METHOD_TYPE, DEFAULT_METHOD,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_THRESHOLD,
g_param_spec_double ("threshold", "Content Threshold",
"Threshold beyond which to consider content different as determined by content-method",
0, G_MAXDOUBLE, DEFAULT_THRESHOLD,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_UPPER,
g_param_spec_boolean ("upper", "Threshold Upper Bound",
"Whether threshold value is upper bound or lower bound for difference measure",
DEFAULT_UPPER, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&src_factory));
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&sink_factory));
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&check_sink_factory));
gst_element_class_set_static_metadata (gstelement_class, "Compare buffers",
"Filter/Debug", "Compares incoming buffers",
"Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>");
}
static void
gst_compare_init (GstCompare * comp)
{
comp->cpads = gst_collect_pads_new ();
gst_collect_pads_set_function (comp->cpads,
(GstCollectPadsFunction) GST_DEBUG_FUNCPTR (gst_compare_collect_pads),
comp);
comp->sinkpad = gst_pad_new_from_static_template (&sink_factory, "sink");
GST_PAD_SET_PROXY_CAPS (comp->sinkpad);
gst_element_add_pad (GST_ELEMENT (comp), comp->sinkpad);
comp->checkpad =
gst_pad_new_from_static_template (&check_sink_factory, "check");
gst_pad_set_query_function (comp->checkpad, gst_compare_query);
gst_element_add_pad (GST_ELEMENT (comp), comp->checkpad);
gst_collect_pads_add_pad (comp->cpads, comp->sinkpad,
sizeof (GstCollectData), NULL, TRUE);
gst_collect_pads_add_pad (comp->cpads, comp->checkpad,
sizeof (GstCollectData), NULL, TRUE);
comp->srcpad = gst_pad_new_from_static_template (&src_factory, "src");
gst_pad_set_query_function (comp->srcpad, gst_compare_query);
gst_element_add_pad (GST_ELEMENT (comp), comp->srcpad);
/* init properties */
comp->meta = DEFAULT_META;
comp->offset_ts = DEFAULT_OFFSET_TS;
comp->method = DEFAULT_METHOD;
comp->threshold = DEFAULT_THRESHOLD;
comp->upper = DEFAULT_UPPER;
gst_compare_reset (comp);
}
static void
gst_compare_reset (GstCompare * comp)
{
}
static gboolean
gst_compare_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
GstCompare *comp;
GstPad *otherpad;
comp = GST_COMPARE (parent);
otherpad = (pad == comp->srcpad ? comp->sinkpad : comp->srcpad);
return gst_pad_peer_query (otherpad, query);
}
static void
gst_compare_meta (GstCompare * comp, GstBuffer * buf1, GstCaps * caps1,
GstBuffer * buf2, GstCaps * caps2)
{
gint flags = 0;
if (comp->meta & GST_BUFFER_COPY_FLAGS) {
if (GST_BUFFER_FLAGS (buf1) != GST_BUFFER_FLAGS (buf2)) {
flags |= GST_BUFFER_COPY_FLAGS;
GST_DEBUG_OBJECT (comp, "flags %d != flags %d", GST_BUFFER_FLAGS (buf1),
GST_BUFFER_FLAGS (buf2));
}
}
if (comp->meta & GST_BUFFER_COPY_TIMESTAMPS) {
if (GST_BUFFER_TIMESTAMP (buf1) != GST_BUFFER_TIMESTAMP (buf2)) {
flags |= GST_BUFFER_COPY_TIMESTAMPS;
GST_DEBUG_OBJECT (comp,
"ts %" GST_TIME_FORMAT " != ts %" GST_TIME_FORMAT,
GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf1)),
GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf2)));
}
if (GST_BUFFER_DURATION (buf1) != GST_BUFFER_DURATION (buf2)) {
flags |= GST_BUFFER_COPY_TIMESTAMPS;
GST_DEBUG_OBJECT (comp,
"dur %" GST_TIME_FORMAT " != dur %" GST_TIME_FORMAT,
GST_TIME_ARGS (GST_BUFFER_DURATION (buf1)),
GST_TIME_ARGS (GST_BUFFER_DURATION (buf2)));
}
if (comp->offset_ts) {
if (GST_BUFFER_OFFSET (buf1) != GST_BUFFER_OFFSET (buf2)) {
flags |= GST_BUFFER_COPY_TIMESTAMPS;
GST_DEBUG_OBJECT (comp,
"offset %" G_GINT64_FORMAT " != offset %" G_GINT64_FORMAT,
GST_BUFFER_OFFSET (buf1), GST_BUFFER_OFFSET (buf2));
}
if (GST_BUFFER_OFFSET_END (buf1) != GST_BUFFER_OFFSET_END (buf2)) {
flags |= GST_BUFFER_COPY_TIMESTAMPS;
GST_DEBUG_OBJECT (comp,
"offset_end %" G_GINT64_FORMAT " != offset_end %" G_GINT64_FORMAT,
GST_BUFFER_OFFSET_END (buf1), GST_BUFFER_OFFSET_END (buf2));
}
}
}
#if 0
/* FIXME ?? */
if (comp->meta & GST_BUFFER_COPY_CAPS) {
if (!gst_caps_is_equal (caps1, caps2)) {
flags |= GST_BUFFER_COPY_CAPS;
GST_DEBUG_OBJECT (comp,
"caps %" GST_PTR_FORMAT " != caps %" GST_PTR_FORMAT, caps1, caps2);
}
}
#endif
/* signal mismatch by debug and message */
if (flags) {
GST_WARNING_OBJECT (comp, "buffers %p and %p failed metadata match %d",
buf1, buf2, flags);
gst_element_post_message (GST_ELEMENT (comp),
gst_message_new_element (GST_OBJECT (comp),
gst_structure_new ("delta", "meta", G_TYPE_INT, flags, NULL)));
}
}
/* when comparing contents, it is already ensured sizes are equal */
static gint
gst_compare_mem (GstCompare * comp, GstBuffer * buf1, GstCaps * caps1,
GstBuffer * buf2, GstCaps * caps2)
{
GstMapInfo map1, map2;
gint c;
gst_buffer_map (buf1, &map1, GST_MAP_READ);
gst_buffer_map (buf2, &map2, GST_MAP_READ);
c = memcmp (map1.data, map2.data, map1.size);
gst_buffer_unmap (buf1, &map1);
gst_buffer_unmap (buf2, &map2);
return c ? 1 : 0;
}
static gint
gst_compare_max (GstCompare * comp, GstBuffer * buf1, GstCaps * caps1,
GstBuffer * buf2, GstCaps * caps2)
{
gint i, delta = 0;
gint8 *data1, *data2;
GstMapInfo map1, map2;
gst_buffer_map (buf1, &map1, GST_MAP_READ);
gst_buffer_map (buf2, &map2, GST_MAP_READ);
data1 = (gint8 *) map1.data;
data2 = (gint8 *) map2.data;
/* primitive loop */
for (i = 0; i < map1.size; i++) {
gint diff = ABS (*data1 - *data2);
if (diff > 0)
GST_LOG_OBJECT (comp, "diff at %d = %d", i, diff);
delta = MAX (delta, ABS (*data1 - *data2));
data1++;
data2++;
}
gst_buffer_unmap (buf1, &map1);
gst_buffer_unmap (buf2, &map2);
return delta;
}
static double
gst_compare_ssim_window (GstCompare * comp, guint8 * data1, guint8 * data2,
gint width, gint height, gint step, gint stride)
{
gint count = 0, i, j;
gint sum1 = 0, sum2 = 0, ssum1 = 0, ssum2 = 0, acov = 0;
gdouble avg1, avg2, var1, var2, cov;
const gdouble k1 = 0.01;
const gdouble k2 = 0.03;
const gdouble L = 255.0;
const gdouble c1 = (k1 * L) * (k1 * L);
const gdouble c2 = (k2 * L) * (k2 * L);
/* For empty images, return maximum similarity */
if (height <= 0 || width <= 0)
return 1.0;
/* plain and simple; no fancy optimizations */
for (i = 0; i < height; i++) {
for (j = 0; j < width; j++) {
sum1 += *data1;
sum2 += *data2;
ssum1 += *data1 * *data1;
ssum2 += *data2 * *data2;
acov += *data1 * *data2;
count++;
data1 += step;
data2 += step;
}
data1 -= j * step;
data2 -= j * step;
data1 += stride;
data2 += stride;
}
avg1 = sum1 / count;
avg2 = sum2 / count;
var1 = ssum1 / count - avg1 * avg1;
var2 = ssum2 / count - avg2 * avg2;
cov = acov / count - avg1 * avg2;
return (2 * avg1 * avg2 + c1) * (2 * cov + c2) /
((avg1 * avg1 + avg2 * avg2 + c1) * (var1 + var2 + c2));
}
/* @width etc are for the particular component */
static gdouble
gst_compare_ssim_component (GstCompare * comp, guint8 * data1, guint8 * data2,
gint width, gint height, gint step, gint stride)
{
const gint window = 16;
gdouble ssim_sum = 0;
gint count = 0, i, j;
for (j = 0; j + (window / 2) < height; j += (window / 2)) {
for (i = 0; i + (window / 2) < width; i += (window / 2)) {
gdouble ssim;
ssim = gst_compare_ssim_window (comp, data1 + step * i + j * stride,
data2 + step * i + j * stride,
MIN (window, width - i), MIN (window, height - j), step, stride);
GST_LOG_OBJECT (comp, "ssim for %dx%d at (%d, %d) = %f", window, window,
i, j, ssim);
ssim_sum += ssim;
count++;
}
}
/* For empty images, return maximum similarity */
if (count == 0)
return 1.0;
return (ssim_sum / count);
}
static gdouble
gst_compare_ssim (GstCompare * comp, GstBuffer * buf1, GstCaps * caps1,
GstBuffer * buf2, GstCaps * caps2)
{
GstVideoInfo info1, info2;
GstVideoFrame frame1, frame2;
gint i, comps;
gdouble cssim[4], ssim, c[4] = { 1.0, 0.0, 0.0, 0.0 };
if (!caps1)
goto invalid_input;
if (!gst_video_info_from_caps (&info1, caps1))
goto invalid_input;
if (!caps2)
goto invalid_input;
if (!gst_video_info_from_caps (&info2, caps1))
goto invalid_input;
if (GST_VIDEO_INFO_FORMAT (&info1) != GST_VIDEO_INFO_FORMAT (&info2) ||
GST_VIDEO_INFO_WIDTH (&info1) != GST_VIDEO_INFO_WIDTH (&info2) ||
GST_VIDEO_INFO_HEIGHT (&info1) != GST_VIDEO_INFO_HEIGHT (&info2))
return comp->threshold + 1;
comps = GST_VIDEO_INFO_N_COMPONENTS (&info1);
/* note that some are reported both yuv and gray */
for (i = 0; i < comps; ++i)
c[i] = 1.0;
/* increase luma weight if yuv */
if (GST_VIDEO_INFO_IS_YUV (&info1) && (comps > 1))
c[0] = comps - 1;
for (i = 0; i < comps; ++i)
c[i] /= (GST_VIDEO_INFO_IS_YUV (&info1) && (comps > 1)) ?
2 * (comps - 1) : comps;
gst_video_frame_map (&frame1, &info1, buf1, GST_MAP_READ);
gst_video_frame_map (&frame2, &info2, buf2, GST_MAP_READ);
for (i = 0; i < comps; i++) {
gint cw, ch, step, stride;
/* only support most common formats */
if (GST_VIDEO_INFO_COMP_DEPTH (&info1, i) != 8)
goto unsupported_input;
cw = GST_VIDEO_FRAME_COMP_WIDTH (&frame1, i);
ch = GST_VIDEO_FRAME_COMP_HEIGHT (&frame1, i);
step = GST_VIDEO_FRAME_COMP_PSTRIDE (&frame1, i);
stride = GST_VIDEO_FRAME_COMP_STRIDE (&frame1, i);
GST_LOG_OBJECT (comp, "component %d", i);
cssim[i] = gst_compare_ssim_component (comp,
GST_VIDEO_FRAME_COMP_DATA (&frame1, i),
GST_VIDEO_FRAME_COMP_DATA (&frame2, i), cw, ch, step, stride);
GST_LOG_OBJECT (comp, "ssim[%d] = %f", i, cssim[i]);
}
gst_video_frame_unmap (&frame1);
gst_video_frame_unmap (&frame2);
#ifndef GST_DISABLE_GST_DEBUG
for (i = 0; i < 4; i++) {
GST_DEBUG_OBJECT (comp, "ssim[%d] = %f, c[%d] = %f", i, cssim[i], i, c[i]);
}
#endif
ssim = cssim[0] * c[0] + cssim[1] * c[1] + cssim[2] * c[2] + cssim[3] * c[3];
return ssim;
/* ERRORS */
invalid_input:
{
GST_ERROR_OBJECT (comp, "ssim method needs raw video input");
return 0;
}
unsupported_input:
{
GST_ERROR_OBJECT (comp, "raw video format not supported %" GST_PTR_FORMAT,
caps1);
return 0;
}
}
static void
gst_compare_buffers (GstCompare * comp, GstBuffer * buf1, GstCaps * caps1,
GstBuffer * buf2, GstCaps * caps2)
{
gdouble delta = 0;
gsize size1, size2;
/* first check metadata */
gst_compare_meta (comp, buf1, caps1, buf2, caps2);
size1 = gst_buffer_get_size (buf1);
size2 = gst_buffer_get_size (buf1);
/* check content according to method */
/* but at least size should match */
if (size1 != size2) {
delta = comp->threshold + 1;
} else {
GstMapInfo map1, map2;
gst_buffer_map (buf1, &map1, GST_MAP_READ);
gst_buffer_map (buf2, &map2, GST_MAP_READ);
GST_MEMDUMP_OBJECT (comp, "buffer 1", map1.data, map2.size);
GST_MEMDUMP_OBJECT (comp, "buffer 2", map2.data, map2.size);
gst_buffer_unmap (buf1, &map1);
gst_buffer_unmap (buf2, &map2);
switch (comp->method) {
case GST_COMPARE_METHOD_MEM:
delta = gst_compare_mem (comp, buf1, caps1, buf2, caps2);
break;
case GST_COMPARE_METHOD_MAX:
delta = gst_compare_max (comp, buf1, caps1, buf2, caps2);
break;
case GST_COMPARE_METHOD_SSIM:
delta = gst_compare_ssim (comp, buf1, caps1, buf2, caps2);
break;
default:
g_assert_not_reached ();
break;
}
}
if ((comp->upper && delta > comp->threshold) ||
(!comp->upper && delta < comp->threshold)) {
GST_WARNING_OBJECT (comp, "buffers %p and %p failed content match %f",
buf1, buf2, delta);
gst_element_post_message (GST_ELEMENT (comp),
gst_message_new_element (GST_OBJECT (comp),
gst_structure_new ("delta", "content", G_TYPE_DOUBLE, delta,
NULL)));
}
}
static GstFlowReturn
gst_compare_collect_pads (GstCollectPads * cpads, GstCompare * comp)
{
GstBuffer *buf1, *buf2;
GstCaps *caps1, *caps2;
buf1 = gst_collect_pads_pop (comp->cpads,
gst_pad_get_element_private (comp->sinkpad));
caps1 = gst_pad_get_current_caps (comp->sinkpad);
buf2 = gst_collect_pads_pop (comp->cpads,
gst_pad_get_element_private (comp->checkpad));
caps2 = gst_pad_get_current_caps (comp->checkpad);
if (!buf1 && !buf2) {
gst_pad_push_event (comp->srcpad, gst_event_new_eos ());
return GST_FLOW_EOS;
} else if (buf1 && buf2) {
gst_compare_buffers (comp, buf1, caps1, buf2, caps2);
} else {
GST_WARNING_OBJECT (comp, "buffer %p != NULL", buf1 ? buf1 : buf2);
comp->count++;
gst_element_post_message (GST_ELEMENT (comp),
gst_message_new_element (GST_OBJECT (comp),
gst_structure_new ("delta", "count", G_TYPE_INT, comp->count,
NULL)));
}
if (buf1)
gst_pad_push (comp->srcpad, buf1);
if (buf2)
gst_buffer_unref (buf2);
if (caps1)
gst_caps_unref (caps1);
if (caps2)
gst_caps_unref (caps2);
return GST_FLOW_OK;
}
static void
gst_compare_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstCompare *comp = GST_COMPARE (object);
switch (prop_id) {
case PROP_META:
comp->meta = g_value_get_flags (value);
break;
case PROP_OFFSET_TS:
comp->offset_ts = g_value_get_boolean (value);
break;
case PROP_METHOD:
comp->method = g_value_get_enum (value);
break;
case PROP_THRESHOLD:
comp->threshold = g_value_get_double (value);
break;
case PROP_UPPER:
comp->upper = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_compare_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstCompare *comp = GST_COMPARE (object);
switch (prop_id) {
case PROP_META:
g_value_set_flags (value, comp->meta);
break;
case PROP_OFFSET_TS:
g_value_set_boolean (value, comp->offset_ts);
break;
case PROP_METHOD:
g_value_set_enum (value, comp->method);
break;
case PROP_THRESHOLD:
g_value_set_double (value, comp->threshold);
break;
case PROP_UPPER:
g_value_set_boolean (value, comp->upper);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstStateChangeReturn
gst_compare_change_state (GstElement * element, GstStateChange transition)
{
GstCompare *comp = GST_COMPARE (element);
GstStateChangeReturn ret;
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
case GST_STATE_CHANGE_READY_TO_PAUSED:
gst_collect_pads_start (comp->cpads);
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
gst_collect_pads_stop (comp->cpads);
break;
default:
break;
}
ret = GST_CALL_PARENT_WITH_DEFAULT (GST_ELEMENT_CLASS, change_state,
(element, transition), GST_STATE_CHANGE_SUCCESS);
if (ret != GST_STATE_CHANGE_SUCCESS)
return ret;
switch (transition) {
case GST_STATE_CHANGE_PAUSED_TO_READY:
gst_compare_reset (comp);
break;
default:
break;
}
return GST_STATE_CHANGE_SUCCESS;
}