title: GStreamer shmsrc and x264enc do not work together
body: <p>I am trying to forward a video between two GStreamer pipelines by using shmsink/shmsrc, and make the receiving side to encode the video. </p>
  
  <p>The following is a command line for the sending side:</p>
  
  <pre><code>gst-launch-0.10 -v videotestsrc \
    ! 'video/x-raw-yuv, format=(fourcc)"I420", framerate=30/1, width=1280, height=720' \
    ! shmsink socket-path=/tmp/xxx shm-size=10000000 wait-for-connection=0 sync=false
  </code></pre>
  
  <p>The following is a command line for the receiving side:</p>
  
  <pre><code>gst-launch-0.10 -v shmsrc socket-path=/tmp/xxx \
    ! 'video/x-raw-yuv, format=(fourcc)"I420", framerate=30/1, width=1280, height=720' \
    ! x264enc
    ! filesink location=/tmp/yyy
  </code></pre>
  
  <p>A problem is that nothing is recorded. It seems that the pipeline is not rolling. The below shows the output message:</p>
  
  <pre><code>Setting pipeline to PAUSED ...
  Pipeline is PREROLLING ...
  /GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = video/x-raw-yuv, format=(fourcc)I420, framerate=(fraction)30/1, width=(int)1280, height=(int)720
  /GstPipeline:pipeline0/GstX264Enc:x264enc0.GstPad:src: caps = video/x-h264, width=(int)1280, height=(int)720, framerate=(fraction)30/1, pixel-aspect-ratio=(fraction)1/1, codec_data=(buffer)014d401fffe10018674d401feca02802dd8088000003000bb9aca00078c18cb001000468ebecb2, stream-format=(string)avc, alignment=(string)au, level=(string)3.1, profile=(string)main
  /GstPipeline:pipeline0/GstX264Enc:x264enc0.GstPad:sink: caps = video/x-raw-yuv, format=(fourcc)I420, framerate=(fraction)30/1, width=(int)1280, height=(int)720
  </code></pre>
  
  <p>When I remove x264enc as below, the pipeline is rolling and the output file, /tmp/yyy is increasing.</p>
  
  <pre><code>gst-launch-0.10 -v shmsrc socket-path=/tmp/xxx \
    ! 'video/x-raw-yuv, format=(fourcc)"I420", framerate=30/1, width=1280, height=720' \
    ! filesink location=/tmp/yyy
  </code></pre>
  
  <p>Interestingly the output message below shows "New clock: GstSytemclock" which was not shown previously.</p>
  
  <pre><code>Setting pipeline to PAUSED ...
  Pipeline is PREROLLING ...
  /GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = video/x-raw-yuv, format=(fourcc)I420, framerate=(fraction)30/1, width=(int)1280, height=(int)720
  /GstPipeline:pipeline0/GstFileSink:filesink0.GstPad:sink: caps = video/x-raw-yuv, format=(fourcc)I420, framerate=(fraction)30/1, width=(int)1280, height=(int)720
  Pipeline is PREROLLED ...
  Setting pipeline to PLAYING ...
  New clock: GstSystemClock
  </code></pre>
  
  <p>I have no idea why the pipeline does not work with x264enc. Any help will be really appreciated.</p>