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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Yes, do both.
<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> gstreamer-devel [mailto:gstreamer-devel-bounces@lists.freedesktop.org]
<b>Im Auftrag von </b>Jorge Fernandez Monteagudo<br>
<b>Gesendet:</b> Dienstag, 4. April 2017 14:35<br>
<b>An:</b> Discussion of the development of and with GStreamer <gstreamer-devel@lists.freedesktop.org><br>
<b>Betreff:</b> Re: gst_element_set_state question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p><span style="color:black">Hi!<o:p></o:p></span></p>
<p><span style="color:black"><o:p> </o:p></span></p>
<p><span style="color:black">Thanks for your answer! And is there any way to check if the state change has hit an error? Maybe capturing the<o:p></o:p></span></p>
<p><span style="color:black">'GST_MESSAGE_ERROR' event? I supposse I have to wait until the pipeline has change its state, isn't it?<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">De:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"> gstreamer-devel <<a href="mailto:gstreamer-devel-bounces@lists.freedesktop.org">gstreamer-devel-bounces@lists.freedesktop.org</a>>
en nombre de Thornton, Keith <<a href="mailto:keith.thornton@zeiss.com">keith.thornton@zeiss.com</a>><br>
<b>Enviado:</b> martes, 4 de abril de 2017 14:30:31<br>
<b>Para:</b> Discussion of the development of and with GStreamer<br>
<b>Asunto:</b> AW: gst_element_set_state question</span> <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif">Hi, you should create a listener for the message bus. Every element posts its state changed message on the bus. When complete, the pipeline also posts a state changed
message on the bus. There are examples in the user manual<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> gstreamer-devel [<a href="mailto:gstreamer-devel-bounces@lists.freedesktop.org">mailto:gstreamer-devel-bounces@lists.freedesktop.org</a>]
<b>Im Auftrag von </b>Jorge Fernandez Monteagudo<br>
<b>Gesendet:</b> Dienstag, 4. April 2017 12:59<br>
<b>An:</b> <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a><br>
<b>Betreff:</b> gst_element_set_state question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p><span style="font-family:"Calibri",sans-serif;color:black">Hi all!<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">I would like to know what the correct way to wait for a state change in gstreamer.<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">I'm using a typical code doing a polling after the 'gst_element_set_state' call but<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">sometimes, with the machine under a heavy load, I get a timeout but gstreamer<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">is still working and finally changes the state.<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">Is there a better way? Is it possible to wait without timeout and look for some<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">error trying to change the state? What timeout is considered safe?<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">The code waiting for a state change with a 10 seconds timeout<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">bool poll_for_state_change( GstState new_state )<br>
{<br>
GTimeVal tfthen, tfnow;<br>
GstClockTimeDiff diff;<br>
GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;<br>
GstState current;<br>
gint32 timeescap = 0;<br>
<br>
gst_element_get_state( pipeline, ¤t, NULL, GST_SECOND );<br>
printf( "%s - change state from %s to %s\n",<br>
__FUNCTION__, gst_element_state_get_name( current ),<br>
gst_element_state_get_name( new_state ) );<br>
if( current == new_state )<br>
return true;<br>
<br>
g_get_current_time( &tfthen );<br>
result = gst_element_set_state( pipeline, new_state );<br>
if( result == GST_STATE_CHANGE_FAILURE )<br>
return false;<br>
<br>
while( 1 ) {<br>
gst_element_get_state( pipeline, ¤t, NULL, GST_SECOND );<br>
g_get_current_time( &tfnow );<br>
diff = GST_TIMEVAL_TO_TIME( tfnow ) - GST_TIMEVAL_TO_TIME( tfthen );<br>
diff /= (1000 * 1000);<br>
timeescap = (unsigned int) diff;<br>
<br>
if( new_state == current )<br>
break;<br>
<br>
if( timeescap > 10000 ) {<br>
printf( "%s - Time out in state transferring from %s to %s\n",<br>
__FUNCTION__, gst_element_state_get_name( current ),<br>
gst_element_state_get_name( new_state ) );<br>
return false;<br>
}<br>
}<br>
<br>
return true;<br>
}<o:p></o:p></span></p>
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<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">Thanks!<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black">Jorge<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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