[gst-devel] gstrtpbin and rtph264depay linking problem

Qin Chen eric.qin.chen at gmail.com
Mon Mar 1 18:55:25 CET 2010


Hi Tiago,

Thank you very much for your reply.

I didn't "request" the recv_rtp_src_%d_%d_%d pad. In my codes, I used
gst_element_link_many(gstrtpbin, rtpdec, vdec, vconv, vsink, NULL); and hope
that I can get the "dynamically" created pad. But according to the error
message, no such pad was created. Any idea? Thanks

Regards,

Qin



On Mon, Mar 1, 2010 at 7:20 AM, Tiago Katcipis <katcipis at inf.ufsc.br> wrote:

>
>
> On Mon, Mar 1, 2010 at 1:24 AM, Qin Chen <eric.qin.chen at gmail.com> wrote:
>
>> Hi experts,
>>
>> I am trying to write a pipeline for receiving and decoding H.264 RTP
>> packets. Please see the C codes below. It is basically equivalent to
>> following pipeline.
>>
>> gst-launch -v gstrtpbin name=rtpbin                                          \
>>     udpsrc caps="application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264" \
>>
>>
>>             port=5000 ! rtpbin.recv_rtp_sink_0                                \
>>         rtpbin. ! rtph264depay ! ffdec_h264 ! xvimagesink                    \
>>
>>
>> But I couldn't link gstrtpbin and rtph264depay. The error message is as
>> follows:
>> 0:00:00.135605335  5934  0x95aa008 INFO        GST_ELEMENT_PADS
>> gstutils.c:1587:gst_element_link_pads: trying to link element
>> gst-rtp-bin:(any) to element rtp-decoder:(any)
>> 0:00:00.135657988  5934  0x95aa008 INFO        GST_ELEMENT_PADS
>> gstelement.c:970:gst_element_get_static_pad: no such pad
>> 'recv_rtp_src_%d_%d_%d' in element "gst-rtp-bin"
>> 0:00:00.135679108  5934  0x95aa008 INFO        GST_ELEMENT_PADS
>> gstutils.c:1208:gst_element_get_compatible_pad:<gst-rtp-bin> Could not find
>> a compatible pad to link to rtp-decoder:sink
>>
>> Could someone give me some hints? Why I have no "recv_rtp_src_%d_%d_%d"?
>
>
>
> http://www.gstreamer.net/data/doc/gstreamer/head/gst-plugins-good-plugins/html/gst-plugins-good-plugins-gstrtpbin.html
>
> as you can see the "recv_rtp_src_%d_%d_%d" pad is created dinamically, you
> cant get it.
>
> "To use GstRtpBin<http://gst-plugins-good-plugins-gstrtpbin.html#GstRtpBin> as
> an RTP receiver, request a recv_rtp_sink_%d pad. The session number must
> be specified in the pad name. Data received on the recv_rtp_sink_%d pad
> will be processed in the GstRtpSession<http://gst-plugins-good-plugins-gstrtpsession.html#GstRtpSession> manager
> and after being validated forwarded on GstRtpSsrcDemux<http://gst-plugins-good-plugins-gstrtpssrcdemux.html#GstRtpSsrcDemux> element.
> Each RTP stream is demuxed based on the SSRC and send to a
> GstRtpJitterBuffer<http://gst-plugins-good-plugins-gstrtpjitterbuffer.html#GstRtpJitterBuffer>.
> After the packets are released from the jitterbuffer, they will be forwarded
> to aGstRtpSsrcDemux<http://gst-plugins-good-plugins-gstrtpssrcdemux.html#GstRtpSsrcDemux> element.
> The GstRtpSsrcDemux<http://gst-plugins-good-plugins-gstrtpssrcdemux.html#GstRtpSsrcDemux> element
> will demux the packets based on the payload type and will create a unique
> pad recv_rtp_src_%d_%d_%d on gstrtpbin with the session number, SSRC and
> payload type respectively as the pad name."
>
>
>> Or could someone lead me to similar examples? Thanks in advance!
>>
>> Regards,
>>
>> Qin
>>
>>
>> static
>> GstElement* construct_receiver_pipeline(void){
>>     GstElement *pipeline, *gstrtpbin, *vdec, *rtpdec, *vsink;
>>     GstElement *jitterbuf, *vconv;
>>     GstElement *udpsrc_rtp;
>>     GstCaps *caps;
>>     GstPad  *pad;
>>     gboolean err;
>>     GstPadLinkReturn res;
>>
>>     //Create gstrtpbin
>>     gstrtpbin = gst_element_factory_make("gstrtpbin", "gst-rtp-bin");
>>     if ( !gstrtpbin ) {
>>         g_printerr("Failed to create gstrtpbin\n");
>>         return 0;
>>     }
>>     g_object_set(G_OBJECT (jitterbuf), "latency", jitter_latency, NULL);
>>
>>     //RTP ource initialization
>>     udpsrc_rtp = gst_element_factory_make("udpsrc", "udp-udpsrc_rtp");
>>     if ( !udpsrc_rtp ) {
>>         g_printerr("Failed to create udpsrc\n");
>>         return 0;
>>     }
>>     g_object_set(G_OBJECT (udpsrc_rtp), "port", rtp_port, NULL);
>>     //gst_caps_new_simple and gst_element_linked_filter don't work
>>     g_object_set(G_OBJECT (udpsrc_rtp), "caps",
>>             gst_caps_from_string("application/x-rtp, "
>>                     "clock-rate=(int)90000, "
>>                     "payload=(int)96, "
>>                     "media=(string)video, "
>>                     "encoding-name=(string)H264"), NULL);
>>
>>     //Create video decoder
>>     vdec = gst_element_factory_make(vdecoder, "video-decoder");
>>     if ( !vdec ) {
>>         g_printerr("Failed to create %s\n", vdecoder);
>>         return 0;
>>     }
>>
>>     //Choose RTP decoder according to video codec
>>     rtpdecoder = g_strdup(select_rtp_decoder(vdecoder));
>>     g_free(vdecoder);
>>
>>     //Create rtp decoder
>>     rtpdec = gst_element_factory_make(rtpdecoder, "rtp-decoder");
>>     if ( !rtpdec ) {
>>         g_printerr("Failed to create %s\n", rtpdecoder);
>>         return 0;
>>     }
>>
>>     //Create video converter
>>     vconv = gst_element_factory_make("ffmpegcolorspace",
>> "video-converter");
>>     if ( !vconv ) {
>>         g_printerr("Failed to create ffmpegcolorspace\n");
>>         return 0;
>>     }
>>
>>     //Create video sink
>>     vsink = gst_element_factory_make("xvimagesink", "video-sink");
>>     if ( !vsink ) {
>>         g_printerr("Failed to create xvimagesink\n");
>>         return 0;
>>     }
>>
>>     /* Set up the pipeline */
>>     gst_bin_add_many(GST_BIN (pipeline), udpsrc_rtp, gstrtpbin/*,
>> jitterbuf*/,
>>             rtpdec, vdec, vconv, vsink, NULL);
>>
>>     //link udpsrc_rtp to gstrtpbin
>>     pad = gst_element_get_request_pad(gstrtpbin, "recv_rtp_sink_%d");
>>     if ( !pad ) {
>>         g_printerr("Failed to create pad\n");
>>         return 0;
>>     }
>>     res = gst_pad_link(gst_element_get_pad(udpsrc_rtp, "src"), pad);
>>     gst_object_unref(GST_OBJECT (pad));
>>     if ( GST_PAD_LINK_FAILED(res)  ) {
>>         g_printerr("Failed to link pads\n");
>>         return 0;
>>     }
>>
>>     err = gst_element_link_many(gstrtpbin, rtpdec, vdec, vconv, vsink,
>> NULL);
>>     if ( err==FALSE ) {
>>         g_printerr("Failed to link elements\n");
>>         return 0;
>>     }
>>
>>     return pipeline;
>> }
>>
>>
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>>
>
>
> ------------------------------------------------------------------------------
> Download Intel&#174; Parallel Studio Eval
> Try the new software tools for yourself. Speed compiling, find bugs
> proactively, and fine-tune applications for parallel performance.
> See why Intel Parallel Studio got high marks during beta.
> http://p.sf.net/sfu/intel-sw-dev
> _______________________________________________
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> gstreamer-devel at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>
>
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