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GstVideoConnector: make sure downstream filter is in correct state.

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When requesting a buffer from downstream filter,
check if downstream element is in NULL state,
and wait for up to 1 second for it to switch.
Otherwise gst_pad_alloc_buffer returns GST_FLOW_WRONG_STATE and
pipeline stalls.

Change-Id: Ic0539c41638ab3bfb548a30043ebe925675b0b6f
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>
This commit is contained in:
Lev Zelenskiy
2012-04-13 17:34:13 +10:00
committed by Qt by Nokia
parent e24f4fed53
commit 1b94f984c9
1 changed files with 37 additions and 0 deletions
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37
src/plugins/gstreamer/gstvideoconnector.c
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@@ -40,6 +40,7 @@
****************************************************************************/
#include "gstvideoconnector.h"
#include <unistd.h>
/* signals */
enum
@@ -185,6 +186,8 @@ gst_video_connector_dispose (GObject * object)
G_OBJECT_CLASS (parent_class)->dispose (object);
}
// "When this function returns anything else than GST_FLOW_OK,
// the buffer allocation failed and buf does not contain valid data."
static GstFlowReturn
gst_video_connector_buffer_alloc (GstPad * pad, guint64 offset, guint size,
GstCaps * caps, GstBuffer ** buf)
@@ -201,11 +204,45 @@ gst_video_connector_buffer_alloc (GstPad * pad, guint64 offset, guint size,
gst_object_ref(element->srcpad);
GST_OBJECT_UNLOCK (element);
// Check if downstream element is in NULL state
// and wait for up to 1 second for it to switch.
GstPad *peerPad = gst_pad_get_peer(element->srcpad);
if (peerPad) {
GstElement *parent = gst_pad_get_parent_element(peerPad);
gst_object_unref (peerPad);
if (parent) {
GstState state;
GstState pending;
int totalTimeout = 0;
// This seems to sleep for about 10ms usually.
while (totalTimeout < 1000000) {
gst_element_get_state(parent, &state, &pending, 0);
if (state != GST_STATE_NULL)
break;
usleep(5000);
totalTimeout += 5000;
}
gst_object_unref (parent);
if (state == GST_STATE_NULL) {
GST_DEBUG_OBJECT (element, "Downstream element is in NULL state");
// Downstream filter seems to be in the wrong state
return GST_FLOW_UNEXPECTED;
}
}
}
res = gst_pad_alloc_buffer(element->srcpad, offset, size, caps, buf);
gst_object_unref (element->srcpad);
GST_DEBUG_OBJECT (element, "buffer alloc finished: %s", gst_flow_get_name (res));
if (res == GST_FLOW_WRONG_STATE) {
// Just in case downstream filter is still somehow in the wrong state.
// Pipeline stalls if we report GST_FLOW_WRONG_STATE.
return GST_FLOW_UNEXPECTED;
}
return res;
}