Thank you! I run the command GST_DEBUG="rademux:4,real*:4" gst-launch playbin uri=file:///home/ruanwen/Desktop/media/04.rmvb [ruanwen@localhost ~]$ GST_DEBUG="rademux:4,real*:4" gst-launch playbin uri=file:///home/ruanwen/Desktop/media/04.rmvb Setting pipeline to PAUSED ... Pipeline is PREROLLING ... 0:00:00.609076891  3349 0x9e14590 DEBUG         realaudiodec gstrealaudiodec.c:365:gst_real_audio_dec_setcaps:<realaudiodec0> Cannot handle version 10. 0:00:00.609383308  3349 0x9e18118 DEBUG         realvideodec gstrealvideodec.c:409:open_library:<realvideodec0> Attempting to open shared library for real video version 4 ERROR: from element /playbin0/decodebin0/rmdemux0: GStreamer encountered a general stream error. Additional debug info: rmdemux.c(943): gst_rmdemux_loop (): /playbin0/decodebin0/rmdemux0: stream stopped, reason not-negotiated ERROR: pipeline doesn't want to preroll. Setting pipeline to NULL ... 0:00:00.692914772  3349 0x9e18118 DEBUG         realvideodec gstrealvideodec.c:115:gst_real_video_dec_chain:<realvideodec0> got buffer of size 1658, timestamp 0:00:00.000000000 0:00:00.692974268  3349 0x9e18118 DEBUG         realvideodec gstrealvideodec.c:217:gst_real_video_dec_chain:<realvideodec0> buffer alloc failed: wrong-state FREEING pipeline ... The debug shows that it can't handle audio version 10. But how to support the real audio version 10? I have added the codec such as amrn.so amrw.so  atrc.so  colorcvt.so  cook.so  drv1.so  drv2.so  drvc.so  raac.so  ralf.so  rv10.so  rv20.so  rv30.so  rv40.so  sipr.so to the /usr/lib/codec and it seem not to work as before. <div class="gmail_quote">2008/5/13 Stefan Kost <<a href="mailto:ensonic@hora-obscura.de">ensonic@hora-obscura.de</a>>: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hi, Ruan Wen schrieb:<div><div></div><div class="Wj3C7c"> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Hi I have installed the latest gstreamer ,gst-plugins-good,gst-plugins-bad,gst-plugins-ugly.Also the document on the website <a href="http://gstreamer.freedesktop.org/documentation/plugins.html" target="_blank">http://gstreamer.freedesktop.org/documentation/plugins.html</a> shows that the latest versions support the realmedia. I can use the gst-launch to play some rmvb files but not to other rmvb files; For example,i run the next command on the terminal [ruanwen@localhost ~]$ gst-launch playbin uri=file:///home/ruanwen/Desktop/media/04.rmvb Setting pipeline to PAUSED ... Pipeline is PREROLLING ... ERROR: from element /playbin0/decodebin0/rmdemux0: GStreamer encountered a general stream error. Additional debug info: rmdemux.c(943): gst_rmdemux_loop (): /playbin0/decodebin0/rmdemux0: stream stopped, reason not-negotiated ERROR: pipeline doesn't want to preroll. Setting pipeline to NULL ... FREEING pipeline ... If i add some options to the command , it output: [ruanwen@localhost ~]$ gst-launch -m playbin uri=file:///home/ruanwen/Desktop/media/04.rmvb ................ <skip> ................ Got Message from element "rmdemux0" (tag): taglist, audio-codec=(string)"Real\ Audio\ 10\ $AAC$"; Got Message from element "rmdemux0" (tag): taglist, video-codec=(string)"Real\ Video\ 4.0"; Got Message from element "fakesink" (state-changed): GstMessageState, old-state=(GstState)GST_STATE_PLAYING, new-state=(GstState)GST_STATE_PAUSED, pending-state=(GstState)GST_STATE_READY; Got Message from element "decodebin0" (state-changed): GstMessageState, old-state=(GstState)GST_STATE_READY, new-state=(GstState)GST_STATE_PAUSED, pending-state=(GstState)GST_STATE_VOID_PENDING; Got Message from element "fakesink" (state-changed): GstMessageState, old-state=(GstState)GST_STATE_READY, new-state=(GstState)GST_STATE_READY, pending-state=(GstState)GST_STATE_NULL; Got Message from element "fakesink" (state-changed): GstMessageState, old-state=(GstState)GST_STATE_READY, new-state=(GstState)GST_STATE_NULL, pending-state=(GstState)GST_STATE_VOID_PENDING; Got Message from element "rmdemux0" (error): GstMessageError, gerror=(GstGError)(NULL), debug=(string)"rmdemux.c$943$:\ gst_rmdemux_loop\ :\ /playbin0/decodebin0/rmdemux0:\012stream\ stopped\,\ reason\ not-negotiated"; ERROR: from element /playbin0/decodebin0/rmdemux0: GStreamer encountered a general stream error. Additional debug info: rmdemux.c(943): gst_rmdemux_loop (): /playbin0/decodebin0/rmdemux0: stream stopped, reason not-negotiated ERROR: pipeline doesn't want to preroll. Setting pipeline to NULL ... FREEING pipeline ... It seem that the gstreamer can't support the RealAudio 10, because the audio codec of other files which can be played normally is RealAudio8 or 9. How can i diagnose the problem and determine which cause the playing failure? </blockquote> </div></div> GST_DEBUG="rademux:4,real*:4" gst-launch playbin uri=file:///home/ruanwen/Desktop/media/04.rmvb Stefan </blockquote></div>