Try using the playbin or decodebin elements with -v option. You can know the elements required to play your file. <div class="gmail_quote">On Tue, May 26, 2009 at 9:20 AM, Arnab Samanta <<a href="mailto:arnabsamanta@tataelxsi.co.in">arnabsamanta@tataelxsi.co.in</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> <div> Hello developes, I am trying to play a .mp4 file through a pipeline and the pipleine structure is as follows gst-launch filesrc location=/root/mpeg4.mp4 ! ffdemux_mov_mp4_m4a_3gp_3g2_mj2 ! ffdec_msmpeg4 ! queue ! sdlvideosink The error message is as follows Setting pipeline to PAUSED ... Pipeline is PREROLLING ... ERROR: from element /pipeline0/ffdemux_mov_mp4_m4a_3gp_3g2_mj20: GStreamer encountered a general supporting library error. Additional debug info: gstffmpegdemux.c(1126): gst_ffmpegdemux_open (): /pipeline0/ffdemux_mov_mp4_m4a_3gp_3g2_mj20: Unhandled error code received ERROR: pipeline doesn't want to preroll. Setting pipeline to NULL ... FREEING pipeline ... I am using ffmpeg-0.10.5. Can any body please tell me what "library" i need to install ? Or do i need to use any other plugin before the demux ? In case it can be done by some other ways, kindly suggest. Thanks in advance Regards, ~Arnab <pre>The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments contained in it. </pre></div> ------------------------------------------------------------------------------ Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers & brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, & iPhoneDevCamp asthey present alongside digital heavyweights like Barbarian Group, R/GA, & Big Spaceship. <a href="http://www.creativitycat.com" target="_blank">http://www.creativitycat.com</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>