title: WARNING: erroneous pipeline: could not link customsrc0 to mpegtsmux0
body: <p>I cannot create a pipeline with gstreamer and I don't know how I can debug it further. </p>
  
  <pre><code>gst-launch-1.0 --gst-debug=GST_CAPS:4 -v -e customsrc num-buffers=1000 ! video/x-h264,width=600,height=600,framerate=1/12,stream-format=byte-stream ! mpegtsmux ! udpsink host=10.92.7.2 port=5000
  WARNING: erroneous pipeline: could not link customsrc0 to mpegtsmux0
  </code></pre>
  
  <p>The capabilities of customsrc and mpegtsmux are matching. But obviously something is missing.</p>
  
  <p><strong>customsrc</strong></p>
  
  <pre><code>Pad Templates:
    SRC template: 'src'
      Availability: Always
      Capabilities:
        video/x-h264
                    width: [ 1, 2147483647 ]
                   height: [ 1, 2147483647 ]
                framerate: [ 1/2147483647, 2147483647/1 ]
            stream-format: avc
                alignment: au
  </code></pre>
  
  <p><strong>mpegtsmux</strong></p>
  
  <pre><code>Pad Templates:
    SINK template: 'sink_%d'
      Availability: On request
        Has request_new_pad() function: 0x76beca8c
      Capabilities:
        video/x-h264
            stream-format: byte-stream
                alignment: { au, nal }
  </code></pre>
  
  <p>What else can I do to figure out the mismatch?</p>