title: gstreamer "Internal data flow error" for videotestsrc
body: <p>I am working on an app using  gstreamer svgoverlay plugin. My hardware platform is AM335x starter kit and OS is Arago linux (ti provided). The gstreamer which is part of the root-fs  does not have the svgoverlay plugin. So I replaced the gstreamer with packages from <a href="http://feeds.angstrom-distribution.org/feeds/unstable/ipk/glibc/armv7a/gstreamer/" rel="nofollow noreferrer">this</a> repo.</p>
  
  <p>A test pipline ("gst-launch-0.10 -v videotestsrc !   fbdevsink") worked without any issue in the original gstreamer. But with the new gstreamer, it fails with  "Internal data flow error". This is the relevant section of the gstreamer debug output :</p>
  
  <pre><code>    0 [36mDEBUG  [00m [00;04m             default gstsegment.c:455:gst_segment_set_newsegment_full:[00m old segment was: 0xdcc00
      0:00:01.737060548 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00m            basesink gstbasesink.c:1455:gst_base_sink_configure_segment:&lt;fbdevsink0&gt;[00m configured NEWSEGMENT update 0, rate 1.000000, applied rate 1.000000, format GST_FORMAT_TIME, 0:00:00.000000000 -- 99:99:99.999999999, time 0:00:00.000000000, accum 0:00:00.000000000
      0:00:01.737182618 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00m            basesink gstbasesink.c:3120:gst_base_sink_queue_object_unlocked:&lt;fbdevsink0&gt;[00m now 0 prerolled items
      0:00:01.737243653 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00m            basesink gstbasesink.c:3173:gst_base_sink_queue_object_unlocked:&lt;fbdevsink0&gt;[00m need more preroll data 0 &lt;= 0
      0:00:01.737335206 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01;31;41m            GST_PADS gstpad.c:5370:gst_pad_send_event:&lt;fbdevsink0:sink&gt;[00m sent event, result 1
      0:00:01.737396241 [336m 1751[00m    0xadf30 [37mLOG    [00m [00;01;31;41m            GST_PADS gstpad.c:5221:gst_pad_push_event:&lt;videotestsrc0:src&gt;[00m sent event to peerpad 0xd30d8, result 1
      0:00:01.737548829 [336m 1751[00m    0xadf30 [37mLOG    [00m [00;01;31;41m            GST_PADS gstpad.c:4683:gst_pad_push:&lt;videotestsrc0:src&gt;[00m Taking slow path
      0:00:01.737640382 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01;31;41m            GST_PADS gstpad.c:4207:gst_pad_chain_data_unchecked:&lt;fbdevsink0:sink&gt;[00m caps changed to 0xcd360 0xcd360
      0:00:01.737762452 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01;34m            GST_CAPS gstpad.c:2761:gst_pad_configure_sink:&lt;fbdevsink0:sink&gt;[00m caps 0xcd360 not accepted
      0:00:01.737854005 [336m 1751[00m    0xadf30 [37mLOG    [00m [00;01;42m          GST_BUFFER gstbuffer.c:195:gst_buffer_finalize:[00m finalize 0xdd270
      0:00:01.738067628 [336m 1751[00m    0xadf30 [37mLOG    [00m [00;01;35m      GST_SCHEDULING gstpad.c:4313:gst_pad_chain_data_unchecked:&lt;fbdevsink0:sink&gt;[00m pushing data but pad did not accept
      0:00:01.738159181 [336m 1751[00m    0xadf30 [32;01mINFO   [00m [00m             basesrc gstbasesrc.c:2511:gst_base_src_loop:&lt;videotestsrc0&gt;[00m pausing after gst_pad_push() = not-negotiated
      0:00:01.738220216 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00m             basesrc gstbasesrc.c:2537:gst_base_src_loop:&lt;videotestsrc0&gt;[00m pausing task, reason not-negotiated
      0:00:01.738281251 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01;31;41m            GST_PADS gstpad.c:5586:gst_pad_pause_task:&lt;videotestsrc0:src&gt;[00m pause task
      0:00:01.738342286 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00m                task gsttask.c:683:gst_task_set_state:&lt;videotestsrc0:src&gt;[00m Changing task 0xe1830 to state 2
      0:00:01.738464357 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01;34m           GST_EVENT gstevent.c:270:gst_event_new:[00m creating new event 0xe0600 eos 86
      0:00:01.738586427 [336m 1751[00m    0xadf30 [33;01mWARN   [00m [00m             basesrc gstbasesrc.c:2574:gst_base_src_loop:&lt;videotestsrc0&gt;[00m error: Internal data flow error.
      0:00:01.738647462 [336m 1751[00m    0xadf30 [33;01mWARN   [00m [00m             basesrc gstbasesrc.c:2574:gst_base_src_loop:&lt;videotestsrc0&gt;[00m error: streaming task paused, reason not-negotiated (-4)
      0:00:01.738739015 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01;37;41m         GST_MESSAGE gstelement.c:1834:gst_element_message_full:&lt;videotestsrc0&gt;[00m start
      0:00:01.738891603 [336m 1751[00m    0xadf30 [32;01mINFO   [00m [00;01;31;47m    GST_ERROR_SYSTEM gstelement.c:1865:gst_element_message_full:&lt;videotestsrc0&gt;[00m posting message: Internal data flow error.
      0:00:01.739044190 [336m 1751[00m    0xadf30 [37mLOG    [00m [00;01;37;41m         GST_MESSAGE gstmessage.c:184:gst_message_init:[00m new message 0x99588
      0:00:01.739105226 [336m 1751[00m    0xadf30 [37mLOG    [00m [00;01;37;41m         GST_MESSAGE gstmessage.c:270:gst_message_new_custom:[00m source videotestsrc0: creating new message 0x99588 error
      0:00:01.739196778 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;43m             GST_BUS gstbus.c:307:gst_bus_post:&lt;bus0&gt;[00m [msg 0x99588] posting on bus, type error, 0xc8848 from source 0xda140
      0:00:01.739288331 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01m                 bin gstbin.c:3091:gst_bin_handle_message_func:&lt;pipeline0&gt;[00m [msg 0x99588] handling child videotestsrc0 message of type error
      0:00:01.739349366 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01m                 bin gstbin.c:3098:gst_bin_handle_message_func:&lt;pipeline0&gt;[00m got ERROR message, unlocking state change
      0:00:01.739440919 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;01m                 bin gstbin.c:3381:gst_bin_handle_message_func:&lt;pipeline0&gt;[00m posting message upward
      0:00:01.739501954 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;43m             GST_BUS gstbus.c:307:gst_bus_post:&lt;bus1&gt;[00m [msg 0x99588] posting on bus, type error, 0xc8848 from source 0xda140
      0:00:01.739562989 [336m 1751[00m    0xadf30 [36mDEBUG  [00m [00;43m             GST_BUS gstbus.c:337:gst_bus_post:&lt;bus1&gt;[00m [msg 0x99588] pushing on async queue
      0:00:01.739898683 [336m 1751[00m    0x16050 [37mLOG    [00m [00;43m             GST_BUS gstbus.c:494:gst_bus_timed_pop_filtered:&lt;bus1&gt;[00m have 2 messages
      0:00:01.740051270 [336m 1751[00m    0x16050 [36mDEBUG  [00m [00;43m             GST_BUS gstbus.c:498:gst_bus_timed_pop_filtered:&lt;bus1&gt;[00m got message 0x99340, state-changed, type mask is 4294967295
      0:00:01.740142823 [336m 1751[00m    0x16050 [36mDEBUG  [00m [00;43m             GST_BUS gstbus.c:759:gst_bus_source_dispatch:&lt;bus1&gt;[00m source 0xadef0 calling dispatch with 0x99340
      0:00:01.740264894 [336m 1751[00m    0x16050 [36mDEBUG  [00m [00;43m             GST_BUS gstbus.c:951:poll_func:[00m mainloop 0x85538 quit
  </code></pre>
  
  <p>I am new to gstreamer, so I am not sure what this error means. Can someone help me out. </p>
  
  <p>NB: I need to use "fbdevsink" because of <a href="https://stackoverflow.com/questions/21990111/why-qt-can-run-without-x-server-and-gtk-cant">this</a>.</p>