Actually i am not very sure where to do it in such elements .  <div class="gmail_quote">2009/8/20 Chen, Weian <<a href="mailto:weian.chen@intel.com">weian.chen@intel.com</a>> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"> <div lang="ZH-CN" vlink="blue" link="blue"> <div>   Take V4l2src as an example, it read data from camera.       <div> thanks, Weian</div> <div> <div style="TEXT-ALIGN: center" align="center"> <hr align="center" width="100%" size="2"> </div> From: sudarshan bisht [mailto:<a href="mailto:bisht.sudarshan@gmail.com" target="_blank">bisht.sudarshan@gmail.com</a>] Sent: 2009年8月20日 13:56 <div> <div></div> <div class="h5"> To: Discussion of the development of GStreamer Subject: Re: [gst-devel] How to send data to next elemnet before calling _chain()</div> </div> </div> <div> <div></div> <div class="h5">   <div>   what is the source element ?  what it reads ? without pushing data how it will stream buffers to next element ? </div> <div>  </div> <div> 2009/8/20 Chen, Weian <<a href="mailto:weian.chen@intel.com" target="_blank">weian.chen@intel.com</a>> <div vlink="blue" link="blue"> <div>   Sorry, actually I should do it in the source element.   So the problem is different, because maybe the source element will not call gst_pad_push at all.   Could you give me some hints?   <div> thanks, Weian</div> <div> <div style="TEXT-ALIGN: center" align="center"> <hr align="center" width="100%" size="2"> </div> From: sudarshan bisht [mailto:<a href="mailto:bisht.sudarshan@gmail.com" target="_blank">bisht.sudarshan@gmail.com</a>] Sent: 2009年8月20日 13:37 <div> <div> To: Discussion of the development of GStreamer Subject: Re: [gst-devel] How to send data to next elemnet before calling _chain() </div></div></div> <div> <div>   <div>    Do it as soon as you get extradata , before calling gst_pad_push .  </div> <div>  </div> <div>  </div> <div> 2009/8/20 Chen, Weian <<a href="mailto:weian.chen@intel.com" target="_blank">weian.chen@intel.com</a>> <div vlink="blue" link="blue"> <div>   Thanks a lot for your help.   Then in demuxer side, where (or which function) these code should put?   <div> thanks, Weian</div> <div> <div style="TEXT-ALIGN: center" align="center"> <hr align="center" width="100%" size="2"> </div> From: sudarshan bisht [mailto:<a href="mailto:bisht.sudarshan@gmail.com" target="_blank">bisht.sudarshan@gmail.com</a>] Sent: 2009年8月20日 12:32 <div> <div> To: Discussion of the development of GStreamer Subject: Re: [gst-devel] How to send data to next elemnet before calling _chain() </div></div></div> <div> <div>   <div>       Hi  ,</div> <div>              I think you can send such extradata using caps .                   </div> <div> So on demuxer side do :---</div> <div>  </div> <div>            GstBuffer *=buf;</div> <div>             buf = gst_buffer_new_and_alloc (size);             memcpy (GST_BUFFER_DATA (buf), the data u want to pass as an extradata (should be guint8*) , size);            gst_caps_set_simple (stream->caps,"codec_data", GST_TYPE_BUFFER, buf, NULL);            gst_buffer_unref (buf);</div> <div>  On Decoder side in _setcaps function u can do :----</div> <div>  </div> <div>  </div> <div>         GstBuffer    *codec_data = NULL;      </div> <div>          guint8* extradata =NULL;</div> <div>         capStruct = gst_caps_get_structure(caps,0);        /* Read extra data passed via demuxer. */         value = gst_structure_get_value(capStruct, "codec_data");     </div> <div>         codec_data = gst_value_get_buffer(value); </div> <div>        </div> <div>         extradata =GST_BUFFER_DATA(codec_data);</div> <div>  </div> <div>         // now u can parse extradata to get your fields .</div> <div>  </div> <div>  </div> <div> 2009/8/20 Chen, Weian <<a href="mailto:weian.chen@intel.com" target="_blank">weian.chen@intel.com</a>> The data I want to send is couple of bytes (some information of current element)  which will be used in next element's _setcap() funct. So we could not wait the gst_pad_push() function to send. thanks, Weian <div> <div> -----Original Message----- From: Michael Smith [mailto:<a href="mailto:msmith@xiph.org" target="_blank">msmith@xiph.org</a>] Sent: 2009年8月20日 1:35 To: Discussion of the development of GStreamer Subject: Re: [gst-devel] How to send data to next elemnet before calling _chain() On Wed, Aug 19, 2009 at 4:41 AM, Chen, Weian<<a href="mailto:weian.chen@intel.com" target="_blank">weian.chen@intel.com</a>> wrote: > Hi All, > > I need to send some data to the next element before calling the _chain > function (such as send the data from src element to encoder element), does > it possible? Can you explain in a bit more detail what you want to do? You normally should call gst_pad_push() to send data to the next element in your pipeline - but that calls the chain function in that next element, so it sounds like you're asking for something different? What data do you want to send? Why do you want to avoid calling the chain function when sending this data? Mike ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now.  <a href="http://p.sf.net/sfu/bobj-july" target="_blank">http://p.sf.net/sfu/bobj-july</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net" target="_blank">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now.  <a href="http://p.sf.net/sfu/bobj-july" target="_blank">http://p.sf.net/sfu/bobj-july</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net" target="_blank">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> </div></div></div> -- Regards, Sudarshan Bisht</div></div></div></div> ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now.  <a href="http://p.sf.net/sfu/bobj-july" target="_blank">http://p.sf.net/sfu/bobj-july</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net" target="_blank">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> </div> -- Regards, Sudarshan Bisht</div></div></div></div> ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now.  <a href="http://p.sf.net/sfu/bobj-july" target="_blank">http://p.sf.net/sfu/bobj-july</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net" target="_blank">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> </div> -- Regards, Sudarshan Bisht</div></div></div></div> ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now.  <a href="http://p.sf.net/sfu/bobj-july" target="_blank">http://p.sf.net/sfu/bobj-july</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> </blockquote></div> <div></div> -- Regards, Sudarshan Bisht