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<body><div>On Wed, Aug 19, 2015, at 13:52, Thiago Santos wrote:<br></div>
<blockquote type="cite"><div>On 08/19/2015 02:42 PM, James Felix
Black wrote:<br></div>
<blockquote type="cite" cite="mid:1440006164.2756501.360488729.41C9CF17@webmail.messagingengine.com"><div>Linux ARM (nVidia Jetson TK1), gstreamer-1.5.2, Qt 5.5,
qt-streamer 1.2.0<br></div>
<div> </div>
<div>I have a simple X11 application that I'm working, based for
now on the qt-gstreamer demo code [1] that plays a video to the
screen, and snapshots "interesting" frames to disk. I'm using Qt
and the qt-gstreamer package, and I am able to access sample
data directly off the pipeline (using the "sample" property at a
given time), and write the raw video to disk as such:<br></div>
<div> </div>
<div><div> QGlib::Value val = pipeline->property("sample");<br></div>
<div> GstSample * v = (GstSample *)g_value_get_boxed(val);<br></div>
<div> </div>
<div> // write the contents of v's memory buffer to disk ....<br></div>
<div> </div>
<div>What I get is a raw file of 4bytes * 1920 * 1080. That's
cool! But what I want to do is:<br></div>
<div> </div>
<div> GstCaps * jpegCaps = gst_caps_new_simple("image/jpeg",
"width", G_TYPE_INT, 640, NULL);<br></div>
<div> GError * err;<br></div>
<div> GstSample * jpeg = gst_video_convert_sample(v, jpegCaps,
100, &err);<br></div>
<div> </div>
<div>... and then write the contents of *that* sample to disk,
instead. However, if I do that conversion, jpeg is null and
the error is:<br></div>
<div> </div>
<div>"Cannot find any image encoder for caps image/jpeg"<br></div>
<div> </div>
<div>OK, that seems fair. But my pipeline (again see the example
code at [1]) is constructed as such:<br></div>
<div> </div>
<div> m_pipeline =
QGst::ElementFactory::make("playbin").dynamicCast<QGst::Pipeline>();<br></div>
<div> </div>
<div>My question then becomes: how should I approach this
problem? Should I modify the pipeline? I see that there's a
"convert-sample" signal on playbin; is that what I should be
using?<br></div>
<div> </div>
<div>Any light anyone can shed would be most welcome.<br></div>
</div>
</blockquote><div> </div>
<div>
Do you have jpegenc (or any other jpeg encoder) in your system?
gst-inspect-1.0 jpegenc should show it. Or gst-inspect-1.0 |grep
jpeg.<br></div>
<div> </div>
</blockquote><div> </div>
<div>I was missing jpegenc; thanks. Having installed it, I now get an "Internal data flow error". <br></div>
<p class="p1"><span class="s1">default convertframe.c:325:gst_video_convert_sample:</span><span class="s2"> Could not convert video frame: Internal data flow error.</span><br></p><div>This is using a one-second timeout on the frame conversion (GST_SECOND). Hmmm. Any pointers here?<br></div>
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