Snapshotting frames from a playbin instance

[James Felix Black]

Will do.

thanks!

On Wed, Aug 19, 2015, at 16:40, Thiago Santos wrote:
> On 08/19/2015 05:35 PM, James Felix
      Black wrote:
>> I ran at DEBUG 2 and didn't get much interesting info., but I
        also just wrote something to read the raw RGBA frame sample data
        and now I can point OpenCV at that.
> Well, it would be nice to debug your case as well to understand what
    was wrong as it seems like it should work. Can you please get a
    GST_DEBUG=6 and attach to a bug in bugzilla.gnome.org under
    GStreamer?
>
>
    Thanks!
>>
>> Cheers.
>>
>>
>> On Wed, Aug 19, 2015, at 16:19, Thiago Santos wrote:
>>> On 08/19/2015 03:46 PM, James Felix Black wrote:
>>>> On Wed, Aug 19, 2015, at 13:52, Thiago Santos wrote:
>>>>> On 08/19/2015 02:42 PM, James Felix Black wrote:
>>>>>> Linux ARM (nVidia Jetson TK1), gstreamer-1.5.2, Qt
                5.5, qt-streamer 1.2.0
>>>>>>
>>>>>> 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:
>>>>>>
>>>>>> QGlib::Value val =
                  pipeline->property("sample");
>>>>>> GstSample * v = (GstSample
                  *)g_value_get_boxed(val);
>>>>>>
>>>>>> // write the contents of v's memory buffer to
                  disk ....
>>>>>>
>>>>>> What I get is a raw file of 4bytes * 1920 * 1080.
                  That's cool! But what I want to do is:
>>>>>>
>>>>>> GstCaps * jpegCaps =
                  gst_caps_new_simple("image/jpeg", "width", G_TYPE_INT,
                  640, NULL);
>>>>>> GError * err;  GstSample * jpeg = gst_video_convert_sample(v,
                  jpegCaps, 100, &err);
>>>>>>
>>>>>> ... and then write the contents of *that* sample to
                  disk, instead. However, if I do that conversion, jpeg
                  is null and the error is:
>>>>>>
>>>>>> "Cannot find any image encoder for caps image/jpeg"
>>>>>>
>>>>>> OK, that seems fair. But my pipeline (again see the
                  example code at [1]) is constructed as such:
>>>>>>
>>>>>> m_pipeline =
QGst::ElementFactory::make("playbin").dynamicCast<QGst::Pipeline>();
>>>>>>
>>>>>> 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?
>>>>>>
>>>>>> Any light anyone can shed would be most welcome.
>>>>>
>>>>> 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.
>>>>>
>>>>
>>>> I was missing jpegenc; thanks. Having installed it, I now
            get an "Internal data flow error".
>>>> default convertframe.c:325:gst_video_convert_sample:
              Could not convert video frame: Internal data flow error.


>>>> This is using a one-second timeout on the frame
            conversion (GST_SECOND). Hmmm. Any pointers here?
>>> I'd recommend using GST_DEBUG to get some log and check
          what exactly was the error.
>>>
>>>
>>>>
>>>>
>>>> _______________________________________________
gstreamer-devel mailing list
>>>> gstreamer-devel at lists.freedesktop.org
>>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>
>>>
>>> --
Thiago Sousa Santos Senior Multimedia Engineer, Open Source Group
Samsung Research America - Silicon Valley
>>> _________________________________________________
>>> gstreamer-devel mailing list gstreamer-devel at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>
>>
>>
>> _______________________________________________
gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
> --
Thiago Sousa Santos Senior Multimedia Engineer, Open Source Group
Samsung Research America - Silicon Valley
> _________________________________________________
> gstreamer-devel mailing list gstreamer-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
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