[gst-devel] Very simple rtsp pipeline exit with error: Could not find a compatible pad to link

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Sat May 23 09:00:40 CEST 2009


Hi,

here is a simple gst-lauch pipeline:

gst-launch-0.10 rtspsrc location=rtsp://<rtspip> latency=100 ! udpsink host=<destinationhost> port=5000

this pipeline works just fine so I decided to assemble it as python code, here is the relevant portion:

self.pipeline = gst.Pipeline("rtsp-pipeline")
source=gst.element_factory_make("rtspsrc","rtsp-source")
source.set_property("location","rtsp://<rtspip>")
source.set_property("latency",100)
destination=gst.element_factory_make("udpsink")
destination.set_property("host","<destinationhost>")
destination.set_property("port",5000)
self.pipeline.add(source,destination)
gst.element_link_many(source,destination)

but this code does't work, there is an error in linking source with destination:

gst.LinkError: failed to link rtsp-source with udpsink0

the relevant log seems:

Could not find a compatible pad to link to udpsink0:sink  

what this means? Any hint to solve?

here is a more detailed log:

0:00:00.000074241  4469       0xb4cfd0 INFO              GST_INIT gst.c:611:init_pre: Initializing GStreamer Core Library version 0.10.23                                                               
0:00:00.000138006  4469       0xb4cfd0 INFO              GST_INIT gst.c:612:init_pre: Using library installed in /usr/lib                                                                               
0:00:00.000154140  4469       0xb4cfd0 INFO              GST_INIT gst.c:622:init_pre: Linux e6500 2.6.29-ARCH #1 SMP PREEMPT Wed May 20 06:42:43 UTC 2009 x86_64                                        
0:00:00.000221746  4469       0xb4cfd0 INFO              GST_INIT gstquery.c:105:_gst_query_initialize: init queries                                                                                    
0:00:00.000869315  4469       0xb4cfd0 INFO              GST_INIT gstmessage.c:73:_gst_message_initialize: init messages                                                                                
0:00:00.003262356  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:261:_gst_plugin_initialize: registering 0 static plugins                                                                  
0:00:00.003410559  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:246:gst_plugin_register_static: registered static plugin "staticelements"                                                 
0:00:00.003426832  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:248:gst_plugin_register_static: added static plugin "staticelements", result: 1                                           
0:00:00.003602064  4469       0xb4cfd0 INFO              GST_INIT gst.c:923:ensure_current_registry: reading registry cache: /home/nicola/.gstreamer-0.10/registry.x86_64.bin                           
0:00:00.015661839  4469       0xb4cfd0 INFO          GST_REGISTRY gstregistrybinary.c:1285:gst_registry_binary_read_cache: loaded /home/nicola/.gstreamer-0.10/registry.x86_64.bin in 0,012036 seconds  
0:00:00.016030181  4470       0xb4cfd0 INFO              GST_INIT gst.c:674:scan_and_update_registry: Validating registry cache: /home/nicola/.gstreamer-0.10/registry.x86_64.bin                       
0:00:00.017439230  4470       0xb4cfd0 INFO              GST_INIT gst.c:759:scan_and_update_registry: Registry cache has not changed                                                                    
0:00:00.017725718  4469       0xb4cfd0 INFO              GST_INIT gst.c:970:ensure_current_registry: registry reading and updating done, result = 1                                                     
0:00:00.017755680  4469       0xb4cfd0 INFO              GST_INIT gst.c:446:gst_init_check: initialized GStreamer successfully                                                                          
0:00:00.028410946  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:567:gst_plugin_load_file: plugin "/usr/lib/gstreamer-0.10/libgstrtsp.so" loaded                                           
0:00:00.028453269  4469       0xb4cfd0 INFO   GST_ELEMENT_FACTORY gstelementfactory.c:377:gst_element_factory_create: creating element "rtspsrc" named "rtsp-source"                                    
0:00:00.029210558  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:567:gst_plugin_load_file: plugin "/usr/lib/gstreamer-0.10/libgstrmdemux.so" loaded                                        
0:00:00.029235701  4469       0xb4cfd0 INFO   GST_ELEMENT_FACTORY gstelementfactory.c:379:gst_element_factory_create: creating element "rtspreal"                                                       
0:00:00.030095866  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:567:gst_plugin_load_file: plugin "/usr/lib/gstreamer-0.10/libgstasf.so" loaded                                            
0:00:00.030122615  4469       0xb4cfd0 INFO   GST_ELEMENT_FACTORY gstelementfactory.c:379:gst_element_factory_create: creating element "rtspwms"                                                        
0:00:00.030903092  4469       0xb4cfd0 INFO    GST_PLUGIN_LOADING gstplugin.c:567:gst_plugin_load_file: plugin "/usr/lib/gstreamer-0.10/libgstudp.so" loaded                                            
0:00:00.030926070  4469       0xb4cfd0 INFO   GST_ELEMENT_FACTORY gstelementfactory.c:379:gst_element_factory_create: creating element "udpsink"                                                        
0:00:00.031001080  4469       0xb4cfd0 INFO      GST_ELEMENT_PADS gstelement.c:641:gst_element_add_pad:<GstBaseSink at 0xdf8110> adding pad 'sink'                                                         
0:00:00.031422013  4469       0xb4cfd0 INFO      GST_ELEMENT_PADS gstutils.c:1338:gst_element_link_pads: trying to link element rtsp-source:(any) to element udpsink0:(any)                             
0:00:00.031473626  4469       0xb4cfd0 INFO      GST_ELEMENT_PADS gstelement.c:884:gst_element_get_static_pad: no such pad 'stream%d' in element "rtsp-source"                                          
0:00:00.031490038  4469       0xb4cfd0 INFO      GST_ELEMENT_PADS gstutils.c:959:gst_element_get_compatible_pad:<rtsp-source> Could not find a compatible pad to link to udpsink0:sink                  
Traceback (most recent call last):                                                                  
  File "test.py", line 59, in <module>                                                        
    s=SimpleTest()                                                                              
  File "test.py", line 10, in __init__                                                        
    self.basePipeline()                                                                             
  File "test.py", line 33, in basePipeline                                                    
    gst.element_link_many(source,destination)                                                       
gst.LinkError: failed to link rtsp-source with udpsink0                                             
0:00:00.034014102  4469       0xb4cfd0 INFO         GST_PARENTAGE gstbin.c:1311:gst_bin_remove_func:<rtsp-pipeline> removed child "udpsink0"                                                            
0:00:00.034044134  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2723:gst_element_dispose:<udpsink0> dispose                                                                              
0:00:00.034057544  4469       0xb4cfd0 INFO      GST_ELEMENT_PADS gstelement.c:759:gst_element_remove_pad:<udpsink0> removing pad 'sink'                                                                
0:00:00.034078775  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2747:gst_element_dispose:<udpsink0> parent class dispose                                                                 
0:00:00.034096864  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2770:gst_element_finalize:<udpsink0> finalize                                                                            
0:00:00.034111321  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2781:gst_element_finalize:<udpsink0> finalize parent                                                                     
0:00:00.034126198  4469       0xb4cfd0 INFO         GST_PARENTAGE gstbin.c:1311:gst_bin_remove_func:<rtsp-pipeline> removed child "rtsp-source"                                                         
0:00:00.034147150  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2723:gst_element_dispose:<rtsp-source> dispose                                                                           
0:00:00.034159023  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2747:gst_element_dispose:<rtsp-source> parent class dispose                                                              
0:00:00.034171804  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2723:gst_element_dispose:<rtspwms0> dispose                                                                              
0:00:00.034183188  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2747:gst_element_dispose:<rtspwms0> parent class dispose                                                                 
0:00:00.034200718  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2770:gst_element_finalize:<rtspwms0> finalize                                                                            
0:00:00.034212242  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2781:gst_element_finalize:<rtspwms0> finalize parent                                                                     
0:00:00.034224464  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2723:gst_element_dispose:<rtspreal0> dispose
0:00:00.034235569  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2747:gst_element_dispose:<rtspreal0> parent class dispose
0:00:00.034248839  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2770:gst_element_finalize:<rtspreal0> finalize
0:00:00.034260363  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2781:gst_element_finalize:<rtspreal0> finalize parent
0:00:00.034279429  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2770:gst_element_finalize:<rtsp-source> finalize
0:00:00.034291093  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2781:gst_element_finalize:<rtsp-source> finalize parent
0:00:00.034303106  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2723:gst_element_dispose:<rtsp-pipeline> dispose
0:00:00.034316655  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2747:gst_element_dispose:<rtsp-pipeline> parent class dispose
0:00:00.034328528  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2770:gst_element_finalize:<rtsp-pipeline> finalize
0:00:00.034339633  4469       0xb4cfd0 INFO       GST_REFCOUNTING gstelement.c:2781:gst_element_finalize:<rtsp-pipeline> finalize parent


thanks
Nicola
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