Hi, i don't know if this is your problem, but when having multiple udpsinks or even one sink (audio/video) + a udpsink, if you don't set the async propertie of the udpsink to false the pipeline will stay blocked on prerroling. hope this helps :-). Best regards, Tiago Katcipis <div class="gmail_quote">On Fri, Aug 6, 2010 at 9:55 AM, 刘兴民 <<a href="mailto:xflxmin17@163.com">xflxmin17@163.com</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi,All Now, I have a problem puzzled me several days. I want to transmit the video and audio to the other computer by 'gstrtpbin'. The pipeline, I used, as the following. diagram 1: +------+ +--------------------+ +------------+ +-------------+ +----> |queue |--->|ffmpegcolorspace |--->| videoscale |--->|autovideosink| / +------+ +---------------------+ +------------+ +-------------+ +----------------+ +---------+ / | |-----> | tee | |+---------------------------------------------------------------------------------------------------> will link for transmit video | | +---------+ \ | +----------------------------+ | | \ +---->| | | | | | | uridecodebin | | transmit bin | | | | | | | /+----> | | | | / | +----------------------------+ | | +----------+ |+------------------------------------------------------------------------------------------------------>will link for transmit audio | |----->| tee | +--------------+ +----------+ \ \ +------+ +-------------+ +-------------+ +---->|queue |--->|audioconvert |--->|autoaudiosink| +------+ +-------------+ +-------------+ diagram 2 (transmit bin): +------------------------------------------------------------------------------------------------------------------------------------------------------------+ | | | +------+ +----------------+ +--------+ +----------+ +-----+ +---------+ +-------+ | | |queue |--->|ffmpegcolorspace|-->|x264enc |-->|rtph264pay|-->|queue|--+ | | -->|udpsink| rtp for video | | +------+ +----------------+ +--------+ +----------+ +-----+ \ | | +-------+ | |--+ / \ +--> |gstrtpbin| +-------+ | | | / | | --> |udpsink| rtcp for video| | |<-+ ghost pad "video_sink" +------+ | | +-------+ | | | rtcp for video |udpsrc|---------------> | | | |--+ +------+ | | | | | | | |--+ +------+ | | +-------+ | | | rtcp for audio |udpsrc|---------------> | |--->|udpsink| rtp for audio | | |<-+ ghost pad "audio_sink" +------+ | | +-------+ | | | \ +------> | | +-------+ | |--+ \ / | |--->|udpsink| rtcp for audio | | +-----+ +------------+ +----+ +--------------+ +-----+ / | | +-------+ | | |queue|-->|audioconvert|-->|faac|-->|rtpmp4apay |-->|queue|-----------+ +----------+ | | +-----+ +------------+ +----+ +---------------+ +-----+ | | | +--------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1)I create a pipeline to playback the media for previewing. As diagram 1. But it hasn't contain the transmit bin. 2)I hang the transmit bin to the pipeline which is in the running state. In order to add the transmit bin dynamicly, I do several steps. 1.add transmit bin to the running pipeline. 2.block video tee element's sink pad, and request a src pad. 3.block audio tee element's sink pad, and request a src pad. 4.link video tee's source pad to transmit bin's "video_sink" ghost pad. 5.link audio tee's source pad to transmit bin's "audio_sink" ghost pad. 6.change the transmit bin's state to running. 7.unblock the double tee's sink pad. In order to receive the media in the recevier end, I need the video and audio's caps.So I set up a signal handle to the 'udpsink'. I can get the video's caps correctly, but I can't get the audio's caps. Note that, the pipeline can playback the video and audio very well. I guess the probem may be in the blocking pad section. I change the blocking order, sometimes I can get the audio caps, but the video caps not . if( !gst_pad_set_blocked(tee0_pad_sink, TRUE) && !gst_pad_set_blocked(tee1_pad_sink, TRUE) ) { g_printerr("pad block failed"); } if( GST_PAD_LINK_FAILED( gst_pad_link(tee0_pad_src1, transmit_bin_video_sink) ) && GST_PAD_LINK_FAILED( gst_pad_link(tee1_pad_src1, transmit_bin_audio_sink) ) ) { g_printerr("tee1 pad link transmit_bin's video/audio sink failed\n"); } gst_element_set_state(transmit_bin, GST_STATE_PLAYING); if( !gst_pad_set_blocked(tee0_pad_sink, FALSE) && !gst_pad_set_blocked(tee1_pad_sink, FALSE) ) { g_printerr("pad unblock failed"); } Please help me. Thanks in advance. ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge <a href="http://p.sf.net/sfu/RIM-dev2dev" target="_blank">http://p.sf.net/sfu/RIM-dev2dev</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> -- <a href="http://www.getgnulinux.org/windows">http://www.getgnulinux.org/windows</a>