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Hey Dev's,<br>
<br>
I've been throwing myself at this problem for a few days without any
significant progress. Hopefully someone can tell me what painfully
obvious part I've overlooked.<br>
<br>
Essentially what I'm trying to do is just grab some frames of video
during playback from an appsink, but it seems my simple pipeline is
missing something vital, because when I get to changing the state to
'paused' or 'playing' the GstStateChangeReturn I recieve is
'GST_STATE_CHANGE_ASYNC (2)'. The debug log doesn't yield any error
output, so I'm a bit unsure of what to look closer at?<br>
<br>
Have I perhaps not hooked something up correctly? What am I missing
here?<br>
<br>
Below is my simple code for trying to hook up this simple pipeline
and grab some frames.<br>
<br>
---------<br>
<br>
std::string launchString = "uridecodebin uri=" + mVideoFileName
+ " ! appsink name=sink";<br>
<br>
mGstPipeline = gst_parse_launch( launchString.c_str(),
&pstGErr1 );<br>
printErrorToConsole( pstGErr1 != nullptr, "GStreamer Error:
Could not construct pipeline", pstGErr1 );<br>
<br>
<br>
GstElement *mPipeline_AppSink;<br>
mPipeline_AppSink = gst_bin_get_by_name( GST_BIN( mGstPipeline
), "sink" );<br>
<br>
//////////////////////////////////////////////////////////////////////////
VIDEO SINK<br>
// Config Video Sink<br>
gst_base_sink_set_sync( GST_BASE_SINK( mPipeline_AppSink ), true
);<br>
gst_app_sink_set_max_buffers( GST_APP_SINK( mPipeline_AppSink ),
8 );<br>
gst_app_sink_set_drop( GST_APP_SINK( mPipeline_AppSink ), true
);<br>
gst_base_sink_set_max_lateness( GST_BASE_SINK( mPipeline_AppSink
), -1 );<br>
<br>
// Set some fix caps for the video sink<br>
// It would seem that GStreamer then tries to transform any
incoming video stream according to these caps<br>
GstCaps* caps = gst_caps_new_simple( "video/x-raw-rgb",<br>
"bpp", G_TYPE_INT, 24,<br>
"depth", G_TYPE_INT, 24,<br>
"endianness", G_TYPE_INT, 4321,<br>
"red_mask", G_TYPE_INT, 0xff0000,<br>
"green_mask", G_TYPE_INT, 0x00ff00,<br>
"blue_mask", G_TYPE_INT, 0x0000ff,<br>
"alpha_mask", G_TYPE_INT, 0x000000ff,<br>
NULL );<br>
<br>
gst_app_sink_set_caps( GST_APP_SINK( mPipeline_AppSink ), caps
);<br>
gst_caps_unref( caps );<br>
<br>
// Set the configured video appsink to the main pipeline<br>
//g_object_set( m_GstPipeline, "video-sink", m_GstVideoSink,
(void*) NULL );<br>
<br>
// Tell the video appsink that it should not emit signals as the
buffer retrieving is handled via callback methods<br>
g_object_set( mPipeline_AppSink, "emit-signals", false, "sync",
true, (void*) NULL );<br>
<br>
GstAppSinkCallbacks cbs; // Does this need to be kept alive?<br>
<br>
// Set Video Sink callback methods<br>
cbs.eos = &GSCinderApp::onEosFromVideoSource;<br>
cbs.new_preroll = &GSCinderApp::onNewPrerollFromVideoSource;<br>
cbs.new_sample = &GSCinderApp::onNewBufferFromVideoSource;<br>
gst_app_sink_set_callbacks( GST_APP_SINK( mPipeline_AppSink ),
&cbs, this, NULL );<br>
<br>
<br>
//////////////////////////////////////////////////////////////////////////
BUS<br>
// Set GstBus<br>
//m_GstBus = gst_pipeline_get_bus( GST_PIPELINE( m_GstPipeline )
);<br>
<br>
if ( mGstPipeline != NULL )<br>
{<br>
// We need to stream the file a little bit in order to be
able to retrieve information from it<br>
GstStateChangeReturn nStateChgRet;<br>
<br>
nStateChgRet = gst_element_set_state( mGstPipeline,
GST_STATE_READY );<br>
printErrorToConsole( nStateChgRet ==
GST_STATE_CHANGE_FAILURE, "GStreamer Error: State Change Failure 1"
);<br>
<br>
nStateChgRet = gst_element_set_state( mGstPipeline,
GST_STATE_PAUSED );<br>
printErrorToConsole( nStateChgRet ==
GST_STATE_CHANGE_FAILURE, "GStreamer Error: State Change Failure 1"
);<br>
<br>
// For some reason this is needed in order to gather video
information such as size, framerate etc ...<br>
GstState state;<br>
gst_element_get_state( mGstPipeline, &state, NULL, 2 *
GST_SECOND ); // Erm... Why get state?<br>
<br>
}<br>
else {<br>
printErrorToConsole( true, "GStreamer Error: Pipeline
Empty?!" );<br>
}<br>
<br>
// Retrieve and store all relevant Media Information<br>
//retrieveVideoInfo();<br>
<br>
// Check if we actually end up playing?<br>
if ( mGstPipeline != NULL )<br>
{<br>
GstStateChangeReturn nStateChgRet;<br>
nStateChgRet = gst_element_set_state( mGstPipeline,
GST_STATE_PAUSED );<br>
printErrorToConsole( nStateChgRet ==
GST_STATE_CHANGE_FAILURE, "GStreamer Error: State Change Failure 3"
);<br>
<br>
}<br>
else {<br>
printErrorToConsole( true, "GStreamer Error: Pipeline
Empty?!" );<br>
}<br>
<br>
----------------<br>
<br>
Regards,<br>
Lasse<br>
<br>
<div class="moz-signature">-- <br>
Lasse Farnung Laursen<br>
Post.doc at the University of Tokyo<br>
<a href="http://www.lasselaursen.com">www.lasselaursen.com</a><br>
FB: <a href="https://www.facebook.com/lasse.laursen">lasse.laursen
</a><br>
Twitter: <a href="https://twitter.com/PMP_J">@PMP_J</a></div>
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