I run this in response to user input:<div><br></div><div><div>void display_pipeline_in_chrome(GstElement *pipeline) {</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>const char* temp_filename = "gst_bin_graph_tmp";</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>char dot_command[1024];</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>char chrome_command[1024];</div><div><br></div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>const char* DIR = getenv("GST_DEBUG_DUMP_DOT_DIR");</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>//GstDebugGraphDetails output_flags = GstDebugGraphDetails(GST_DEBUG_GRAPH_SHOW_MEDIA_TYPE | GST_DEBUG_GRAPH_SHOW_STATES | GST_DEBUG_GRAPH_SHOW_NON_DEFAULT_PARAMS);</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>GstDebugGraphDetails output_flags = GstDebugGraphDetails(GST_DEBUG_GRAPH_SHOW_ALL);</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(pipeline), output_flags, temp_filename);</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>snprintf(dot_command, sizeof(dot_command), "dot -Tpng %s/%s.dot -o %s/%s.png", DIR, temp_filename, DIR, temp_filename);</div><div>
<span class="Apple-tab-span" style="white-space:pre"> </span>snprintf(chrome_command, sizeof(chrome_command), "google-chrome %s/%s.png", DIR, temp_filename);</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>system(dot_command);</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>system(chrome_command);</div><div>}</div><div><br></div><div>It displays the whole pipeline as an image in Chrome, using the Gstreamer debug output from graphviz.</div>
<div><br></div><div>However, that usually isn't enough to tell what's wrong. For example, I recently had a pipeline along these lines:</div><div><br></div><div>appsrc ! ffmpegcolorspace ! theoraenc ! rtptheorapay ! udpsink</div>
<div><br></div><div>This pipeline looked fine in the graph output, so to debug it I used the GST_DEBUG environment variable on each element in the pipeline, starting at the top:</div><div><br></div><div>GST_DEBUG=appsrc:5</div>
<div>--kill and restart</div><div>GST_DEBUG=ffmpegcolorspace:5</div><div>--kill and restart</div><div>GST_DEBUG=theoraenc:5</div><div>--ahhh theoraenc is dropping buffers...</div><div><br></div><div>Doing this one step at a time let me discover which element was blocking. It turns out the problem was I wasn't timestamping the appsrc buffers, and therefore theoraenc was just dropping them.</div>
<br><div class="gmail_quote">On Thu, Aug 9, 2012 at 12:38 PM, Eric Montellese <span dir="ltr"><<a href="mailto:eric.montellese@videon-central.com" target="_blank">eric.montellese@videon-central.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Folks, in development I've run into various malformed or buggy pipelines that give this output:<div><br></div><div>
<div>gst-launch launch ! a ! pipeline</div><div>Setting pipeline to PAUSED ...</div><div>Pipeline is PREROLLING ...</div>
</div><div><br></div><div>Generally I have debugged these issues through a mixture of brute force and intuition (looking for common sorts of problems, etc).</div><div><br></div><div>But perhaps there is a better way to determine which element has held up the pipeline? Some swanky debug command I'm totally unaware of that shows the buffers in-flight perhaps?</div>
<div><br></div><div>Any advice?</div><div><br></div><div>Thanks,</div><div>Eric</div>
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