gstreamer/gst/base/gstbasetransform.c
Wim Taymans 7f4581d977 gst/base/gstbasetransform.*: Make passthrough work using the bufferpools.
Original commit message from CVS:
* gst/base/gstbasetransform.c: (gst_base_transform_init),
(gst_base_transform_transform_caps), (gst_base_transform_getcaps),
(gst_base_transform_configure_caps), (gst_base_transform_setcaps),
(gst_base_transform_get_size), (gst_base_transform_buffer_alloc),
(gst_base_transform_handle_buffer), (gst_base_transform_getrange),
(gst_base_transform_chain), (gst_base_transform_change_state),
(gst_base_transform_set_passthrough),
(gst_base_transform_is_passthrough):
* gst/base/gstbasetransform.h:
Make passthrough work using the bufferpools.
Changed API a bit, subclasses have to write into a buffer
provided by the base class.
More debug info in nego functions.

* gst/elements/gstidentity.c: (gst_identity_init),
(gst_identity_transform):
Port to new base class.
2005-07-15 10:41:32 +00:00

793 lines
21 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
* 2005 Wim Taymans <wim@fluendo.com>
*
* gstbasetransform.c:
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <stdlib.h>
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "../gst-i18n-lib.h"
#include "gstbasetransform.h"
#include <gst/gstmarshal.h>
GST_DEBUG_CATEGORY_STATIC (gst_base_transform_debug);
#define GST_CAT_DEFAULT gst_base_transform_debug
/* BaseTransform signals and args */
enum
{
SIGNAL_HANDOFF,
/* FILL ME */
LAST_SIGNAL
};
enum
{
PROP_0,
};
static GstElementClass *parent_class = NULL;
static void gst_base_transform_base_init (gpointer g_class);
static void gst_base_transform_class_init (GstBaseTransformClass * klass);
static void gst_base_transform_init (GstBaseTransform * trans,
gpointer g_class);
GType
gst_base_transform_get_type (void)
{
static GType base_transform_type = 0;
if (!base_transform_type) {
static const GTypeInfo base_transform_info = {
sizeof (GstBaseTransformClass),
(GBaseInitFunc) gst_base_transform_base_init,
NULL,
(GClassInitFunc) gst_base_transform_class_init,
NULL,
NULL,
sizeof (GstBaseTransform),
0,
(GInstanceInitFunc) gst_base_transform_init,
};
base_transform_type = g_type_register_static (GST_TYPE_ELEMENT,
"GstBaseTransform", &base_transform_info, G_TYPE_FLAG_ABSTRACT);
}
return base_transform_type;
}
static void gst_base_transform_finalize (GObject * object);
static void gst_base_transform_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_base_transform_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static gboolean gst_base_transform_src_activate_pull (GstPad * pad,
gboolean active);
static gboolean gst_base_transform_sink_activate_push (GstPad * pad,
gboolean active);
static guint gst_base_transform_get_size (GstBaseTransform * trans);
static GstElementStateReturn gst_base_transform_change_state (GstElement *
element);
static gboolean gst_base_transform_event (GstPad * pad, GstEvent * event);
static GstFlowReturn gst_base_transform_getrange (GstPad * pad, guint64 offset,
guint length, GstBuffer ** buffer);
static GstFlowReturn gst_base_transform_chain (GstPad * pad,
GstBuffer * buffer);
static GstCaps *gst_base_transform_getcaps (GstPad * pad);
static gboolean gst_base_transform_setcaps (GstPad * pad, GstCaps * caps);
static GstFlowReturn gst_base_transform_buffer_alloc (GstPad * pad,
guint64 offset, guint size, GstCaps * caps, GstBuffer ** buf);
/* static guint gst_base_transform_signals[LAST_SIGNAL] = { 0 }; */
static void
gst_base_transform_base_init (gpointer g_class)
{
GST_DEBUG_CATEGORY_INIT (gst_base_transform_debug, "basetransform", 0,
"basetransform element");
}
static void
gst_base_transform_finalize (GObject * object)
{
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_base_transform_class_init (GstBaseTransformClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = G_OBJECT_CLASS (klass);
gstelement_class = GST_ELEMENT_CLASS (klass);
parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
gobject_class->set_property =
GST_DEBUG_FUNCPTR (gst_base_transform_set_property);
gobject_class->get_property =
GST_DEBUG_FUNCPTR (gst_base_transform_get_property);
gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_base_transform_finalize);
gstelement_class->change_state =
GST_DEBUG_FUNCPTR (gst_base_transform_change_state);
}
static void
gst_base_transform_init (GstBaseTransform * trans, gpointer g_class)
{
GstPadTemplate *pad_template;
GST_DEBUG ("gst_base_transform_init");
pad_template =
gst_element_class_get_pad_template (GST_ELEMENT_CLASS (g_class), "sink");
g_return_if_fail (pad_template != NULL);
trans->sinkpad = gst_pad_new_from_template (pad_template, "sink");
gst_pad_set_getcaps_function (trans->sinkpad,
GST_DEBUG_FUNCPTR (gst_base_transform_getcaps));
gst_pad_set_setcaps_function (trans->sinkpad,
GST_DEBUG_FUNCPTR (gst_base_transform_setcaps));
gst_pad_set_event_function (trans->sinkpad,
GST_DEBUG_FUNCPTR (gst_base_transform_event));
gst_pad_set_chain_function (trans->sinkpad,
GST_DEBUG_FUNCPTR (gst_base_transform_chain));
gst_pad_set_activatepush_function (trans->sinkpad,
GST_DEBUG_FUNCPTR (gst_base_transform_sink_activate_push));
gst_pad_set_bufferalloc_function (trans->sinkpad,
GST_DEBUG_FUNCPTR (gst_base_transform_buffer_alloc));
gst_element_add_pad (GST_ELEMENT (trans), trans->sinkpad);
pad_template =
gst_element_class_get_pad_template (GST_ELEMENT_CLASS (g_class), "src");
g_return_if_fail (pad_template != NULL);
trans->srcpad = gst_pad_new_from_template (pad_template, "src");
gst_pad_set_getcaps_function (trans->srcpad,
GST_DEBUG_FUNCPTR (gst_base_transform_getcaps));
gst_pad_set_setcaps_function (trans->srcpad,
GST_DEBUG_FUNCPTR (gst_base_transform_setcaps));
gst_pad_set_getrange_function (trans->srcpad,
GST_DEBUG_FUNCPTR (gst_base_transform_getrange));
gst_pad_set_activatepull_function (trans->srcpad,
GST_DEBUG_FUNCPTR (gst_base_transform_src_activate_pull));
gst_element_add_pad (GST_ELEMENT (trans), trans->srcpad);
trans->passthrough = FALSE;
}
static GstCaps *
gst_base_transform_transform_caps (GstBaseTransform * trans, GstPad * pad,
GstCaps * caps)
{
GstCaps *ret;
GstBaseTransformClass *klass;
klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
GST_DEBUG_OBJECT (trans, "from: %" GST_PTR_FORMAT, caps);
/* if there is a custom transform function, use this */
if (klass->transform_caps) {
GstCaps *temp;
gint i;
ret = gst_caps_new_empty ();
/* we send caps with just one structure to the transform
* function as this is easier for the element */
for (i = 0; i < gst_caps_get_size (caps); i++) {
GstCaps *nth;
nth = gst_caps_copy_nth (caps, i);
GST_DEBUG_OBJECT (trans, " from: %" GST_PTR_FORMAT, nth);
temp = klass->transform_caps (trans, pad, nth);
gst_caps_unref (nth);
GST_DEBUG_OBJECT (trans, " to : %" GST_PTR_FORMAT, temp);
gst_caps_append (ret, temp);
}
gst_caps_do_simplify (ret);
} else {
/* else use the identity transform */
ret = gst_caps_ref (caps);
}
GST_DEBUG_OBJECT (trans, "to: %" GST_PTR_FORMAT, ret);
return ret;
}
static GstCaps *
gst_base_transform_getcaps (GstPad * pad)
{
GstBaseTransform *trans;
GstPad *otherpad;
GstCaps *caps;
trans = GST_BASE_TRANSFORM (GST_PAD_PARENT (pad));
otherpad = (pad == trans->srcpad) ? trans->sinkpad : trans->srcpad;
/* we can do what the peer can */
caps = gst_pad_peer_get_caps (otherpad);
if (caps) {
GstCaps *temp;
const GstCaps *templ;
GST_DEBUG ("peer caps %" GST_PTR_FORMAT, caps);
/* filtered against our padtemplate */
templ = gst_pad_get_pad_template_caps (otherpad);
GST_DEBUG ("our template %" GST_PTR_FORMAT, templ);
temp = gst_caps_intersect (caps, templ);
GST_DEBUG ("intersected %" GST_PTR_FORMAT, temp);
gst_caps_unref (caps);
/* then see what we can tranform this to */
caps = gst_base_transform_transform_caps (trans, otherpad, temp);
GST_DEBUG ("transformed %" GST_PTR_FORMAT, caps);
gst_caps_unref (temp);
if (caps == NULL)
goto done;
/* and filter against the template again */
templ = gst_pad_get_pad_template_caps (pad);
GST_DEBUG ("our template %" GST_PTR_FORMAT, templ);
temp = gst_caps_intersect (caps, templ);
GST_DEBUG ("intersected %" GST_PTR_FORMAT, temp);
gst_caps_unref (caps);
/* this is what we can do */
caps = temp;
} else {
/* no peer, our padtemplate is enough then */
caps = gst_caps_copy (gst_pad_get_pad_template_caps (pad));
}
done:
GST_DEBUG ("returning %" GST_PTR_FORMAT, caps);
return caps;
}
static gboolean
gst_base_transform_configure_caps (GstBaseTransform * trans, GstCaps * in,
GstCaps * out)
{
gboolean ret = TRUE;
GstBaseTransformClass *klass;
klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
/* no configure the element with the caps */
if (klass->set_caps) {
ret = klass->set_caps (trans, in, out);
}
/* if all goes well, get the size of the output buffer */
if (ret) {
trans->out_size = gst_base_transform_get_size (trans);
GST_DEBUG ("output buffer size %d", trans->out_size);
}
return ret;
}
static gboolean
gst_base_transform_setcaps (GstPad * pad, GstCaps * caps)
{
GstBaseTransform *trans;
GstBaseTransformClass *klass;
GstPad *otherpad, *otherpeer;
GstCaps *othercaps = NULL;
gboolean ret = TRUE;
trans = GST_BASE_TRANSFORM (GST_PAD_PARENT (pad));
klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
otherpad = (pad == trans->srcpad) ? trans->sinkpad : trans->srcpad;
otherpeer = gst_pad_get_peer (otherpad);
if (GST_PAD_IS_IN_SETCAPS (otherpad)) {
ret = TRUE;
goto done;
}
/* see how we can transform the input caps */
othercaps = gst_base_transform_transform_caps (trans, pad, caps);
/* check if transform is empty */
if (!othercaps || gst_caps_is_empty (othercaps))
goto no_transform;
if (!gst_caps_is_fixed (othercaps)) {
GstCaps *temp;
GST_DEBUG ("transform returned non fixed %" GST_PTR_FORMAT, othercaps);
temp = gst_caps_intersect (othercaps, caps);
GST_DEBUG ("intersect returned %" GST_PTR_FORMAT, temp);
if (temp) {
if (!gst_caps_is_empty (temp) && otherpeer) {
GST_DEBUG ("try passthrough with %" GST_PTR_FORMAT, caps);
/* try passthrough. we know it's fixed, because caps is fixed */
if (gst_pad_accept_caps (otherpeer, caps)) {
GST_DEBUG ("peer accepted %" GST_PTR_FORMAT, caps);
gst_caps_unref (othercaps);
othercaps = gst_caps_ref (caps);
/* will fall though. calls accept_caps again, should fix that. */
} else {
GST_DEBUG ("peer did not accept %" GST_PTR_FORMAT, caps);
}
}
gst_caps_unref (temp);
}
}
if (!gst_caps_is_fixed (othercaps) && otherpeer) {
/* intersect against what the peer can do */
GstCaps *peercaps;
GstCaps *intersect;
GST_DEBUG ("othercaps now %" GST_PTR_FORMAT, othercaps);
peercaps = gst_pad_get_caps (otherpeer);
intersect = gst_caps_intersect (peercaps, othercaps);
gst_caps_unref (peercaps);
gst_caps_unref (othercaps);
othercaps = intersect;
GST_DEBUG ("filtering against peer yields %" GST_PTR_FORMAT, othercaps);
}
if (!gst_caps_is_fixed (othercaps)) {
GstCaps *temp;
GST_DEBUG ("othercaps now, trying to fixate %" GST_PTR_FORMAT, othercaps);
/* take first possibility and fixate if necessary */
temp = gst_caps_copy_nth (othercaps, 0);
gst_caps_unref (othercaps);
othercaps = temp;
gst_pad_fixate_caps (otherpad, othercaps);
GST_DEBUG ("after fixating %" GST_PTR_FORMAT, othercaps);
}
/* caps should be fixed now */
if (!gst_caps_is_fixed (othercaps))
goto could_not_fixate;
/* and peer should accept */
if (otherpeer && !gst_pad_accept_caps (otherpeer, othercaps))
goto peer_no_accept;
GST_DEBUG ("got final caps %" GST_PTR_FORMAT, othercaps);
/* we know this will work, we implement the setcaps */
gst_pad_set_caps (otherpad, othercaps);
trans->in_place = gst_caps_is_equal (caps, othercaps);
GST_DEBUG ("in_place: %d", trans->in_place);
/* see if we have to configure the element now */
if (!trans->delay_configure) {
if (pad == trans->sinkpad)
ret = gst_base_transform_configure_caps (trans, caps, othercaps);
else
ret = gst_base_transform_configure_caps (trans, othercaps, caps);
}
done:
if (otherpeer)
gst_object_unref (otherpeer);
if (othercaps)
gst_caps_unref (othercaps);
return ret;
/* ERRORS */
no_transform:
{
GST_DEBUG ("transform returned useless %" GST_PTR_FORMAT, othercaps);
ret = FALSE;
goto done;
}
could_not_fixate:
{
GST_DEBUG ("FAILED to fixate %" GST_PTR_FORMAT, othercaps);
ret = FALSE;
goto done;
}
peer_no_accept:
{
GST_DEBUG ("FAILED to get peer of %" GST_PTR_FORMAT
" to accept %" GST_PTR_FORMAT, otherpad, othercaps);
ret = FALSE;
goto done;
}
}
static guint
gst_base_transform_get_size (GstBaseTransform * trans)
{
guint res = -1;
GstBaseTransformClass *bclass;
bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
if (bclass->get_size) {
res = bclass->get_size (trans);
GST_DEBUG ("get size function returned %d", res);
}
return res;
}
static GstFlowReturn
gst_base_transform_buffer_alloc (GstPad * pad, guint64 offset, guint size,
GstCaps * caps, GstBuffer ** buf)
{
GstBaseTransform *trans;
GstFlowReturn res;
trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
if (trans->in_place) {
/* we can only proxy the bufferpool if we do in_place transforms */
res = gst_pad_alloc_buffer (trans->srcpad, offset, size, caps, buf);
} else {
/* else let the default alloc function allocate a buffer */
*buf = NULL;
res = GST_FLOW_OK;
}
gst_object_unref (trans);
return res;
}
static gboolean
gst_base_transform_event (GstPad * pad, GstEvent * event)
{
GstBaseTransform *trans;
GstBaseTransformClass *bclass;
gboolean ret = FALSE;
gboolean unlock;
trans = GST_BASE_TRANSFORM (GST_PAD_PARENT (pad));
bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
if (bclass->event)
bclass->event (trans, event);
unlock = FALSE;
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_FLUSH:
if (GST_EVENT_FLUSH_DONE (event)) {
GST_STREAM_LOCK (pad);
unlock = TRUE;
}
break;
case GST_EVENT_EOS:
GST_STREAM_LOCK (pad);
unlock = TRUE;
break;
default:
break;
}
ret = gst_pad_event_default (pad, event);
if (unlock)
GST_STREAM_UNLOCK (pad);
return ret;
}
static GstFlowReturn
gst_base_transform_handle_buffer (GstBaseTransform * trans, GstBuffer * inbuf,
GstBuffer ** outbuf)
{
GstBaseTransformClass *bclass;
GstFlowReturn ret = GST_FLOW_OK;
bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
if (trans->in_place) {
if (bclass->transform_ip) {
gst_buffer_ref (inbuf);
/* in place transform and subclass supports method */
ret = bclass->transform_ip (trans, inbuf);
*outbuf = inbuf;
} else {
/* in place transform and subclass does not support method */
if (bclass->transform) {
/* make a copy of the buffer */
*outbuf = inbuf;
inbuf = gst_buffer_copy (inbuf);
ret = bclass->transform (trans, inbuf, *outbuf);
} else {
ret = GST_FLOW_NOT_SUPPORTED;
}
}
} else {
/* figure out the output size */
if (trans->out_size == -1) {
/* ask subclass */
if ((trans->out_size = gst_base_transform_get_size (trans)) == -1)
/* else we have an error */
goto no_size;
}
/* we cannot reconfigure the element yet as we are still processing
* the old buffer. We will therefore delay the reconfiguration of the
* element until we have processed this last buffer. */
trans->delay_configure = TRUE;
/* no in place transform, get buffer, this might renegotiate. */
ret = gst_pad_alloc_buffer (trans->srcpad,
GST_BUFFER_OFFSET (inbuf), trans->out_size,
GST_PAD_CAPS (trans->srcpad), outbuf);
trans->delay_configure = FALSE;
if (ret != GST_FLOW_OK)
goto no_buffer;
gst_buffer_stamp (*outbuf, inbuf);
if (bclass->transform)
ret = bclass->transform (trans, inbuf, *outbuf);
else
ret = GST_FLOW_NOT_SUPPORTED;
if (ret)
ret =
gst_base_transform_configure_caps (trans,
GST_PAD_CAPS (trans->sinkpad), GST_PAD_CAPS (trans->srcpad));
}
gst_buffer_unref (inbuf);
return ret;
/* ERRORS */
no_size:
{
gst_buffer_unref (inbuf);
GST_ELEMENT_ERROR (trans, STREAM, NOT_IMPLEMENTED,
("subclass did not specify output size"),
("subclass did not specify output size"));
return GST_FLOW_ERROR;
}
no_buffer:
{
gst_buffer_unref (inbuf);
GST_DEBUG ("could not get buffer from pool");
return ret;
}
}
static GstFlowReturn
gst_base_transform_getrange (GstPad * pad, guint64 offset,
guint length, GstBuffer ** buffer)
{
GstBaseTransform *trans;
GstFlowReturn ret;
GstBuffer *inbuf;
trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
ret = gst_pad_pull_range (trans->sinkpad, offset, length, &inbuf);
if (ret == GST_FLOW_OK) {
ret = gst_base_transform_handle_buffer (trans, inbuf, buffer);
}
gst_object_unref (trans);
return ret;
}
static GstFlowReturn
gst_base_transform_chain (GstPad * pad, GstBuffer * buffer)
{
GstBaseTransform *trans;
GstFlowReturn ret;
GstBuffer *outbuf;
trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
ret = gst_base_transform_handle_buffer (trans, buffer, &outbuf);
if (ret == GST_FLOW_OK) {
ret = gst_pad_push (trans->srcpad, outbuf);
}
gst_object_unref (trans);
return ret;
}
static void
gst_base_transform_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstBaseTransform *trans;
trans = GST_BASE_TRANSFORM (object);
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_base_transform_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstBaseTransform *trans;
trans = GST_BASE_TRANSFORM (object);
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_base_transform_sink_activate_push (GstPad * pad, gboolean active)
{
gboolean result = TRUE;
GstBaseTransform *trans;
GstBaseTransformClass *bclass;
trans = GST_BASE_TRANSFORM (GST_OBJECT_PARENT (pad));
bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
if (active) {
if (bclass->start)
result = bclass->start (trans);
}
return result;
}
static gboolean
gst_base_transform_src_activate_pull (GstPad * pad, gboolean active)
{
gboolean result = FALSE;
GstBaseTransform *trans;
GstBaseTransformClass *bclass;
trans = GST_BASE_TRANSFORM (GST_OBJECT_PARENT (pad));
bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
result = gst_pad_activate_pull (trans->sinkpad, active);
if (active) {
if (result && bclass->start)
result &= bclass->start (trans);
}
return result;
}
static GstElementStateReturn
gst_base_transform_change_state (GstElement * element)
{
GstBaseTransform *trans;
GstBaseTransformClass *bclass;
GstElementState transition;
GstElementStateReturn result;
trans = GST_BASE_TRANSFORM (element);
bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
transition = GST_STATE_TRANSITION (element);
switch (transition) {
case GST_STATE_NULL_TO_READY:
break;
case GST_STATE_READY_TO_PAUSED:
GST_LOCK (trans);
trans->in_place = trans->passthrough;
trans->out_size = -1;
GST_UNLOCK (trans);
break;
case GST_STATE_PAUSED_TO_PLAYING:
break;
default:
break;
}
result = GST_ELEMENT_CLASS (parent_class)->change_state (element);
switch (transition) {
case GST_STATE_PLAYING_TO_PAUSED:
break;
case GST_STATE_PAUSED_TO_READY:
if (bclass->stop)
result = bclass->stop (trans);
break;
case GST_STATE_READY_TO_NULL:
break;
default:
break;
}
return result;
}
/**
* gst_base_transform_set_passthrough:
* @trans: the #GstBaseTransform to set
* @passthrough: boolean indicating passthrough mode.
*
* Set passthrough mode for this filter by default. This is mostly
* usefull for filters that do not care about negotiation.
*
* MT safe.
*/
void
gst_base_transform_set_passthrough (GstBaseTransform * trans,
gboolean passthrough)
{
g_return_if_fail (trans != NULL);
GST_LOCK (trans);
trans->passthrough = passthrough;
GST_UNLOCK (trans);
}
/**
* gst_base_transform_is_passthrough:
* @trans: the #GstBaseTransform to query
*
* See if @trans is configured as a passthrough transform.
*
* Returns: TRUE is the transform is configured in passthrough mode.
*
* MT safe.
*/
gboolean
gst_base_transform_is_passthrough (GstBaseTransform * trans)
{
gboolean result;
g_return_val_if_fail (trans != NULL, FALSE);
GST_LOCK (trans);
result = trans->passthrough;
GST_UNLOCK (trans);
return result;
}