OpenCv Mat to GstBuffer -> appsrc, possible buffer underflow?

[Mailing List SVR]

Hi,

you can use the gstreamer dewarp plugin available in git master

https://cgit.freedesktop.org/gstreamer/gst-plugins-bad/tree/ext/opencv/gstdewarp.cpp

please report here if you have any issues with your fisheye image,

Nicola


Il 03/02/2017 14:06, borisRobson ha scritto:
> Hi all
>
> I have a project which aims to de-warp a fisheye camera, using two gstreamer
> pipelines with opencv processing in between:
> |   input-pipe                              |   OpenCV processing
> |  output-pipe
> |  rtsprc -> decodebin -> appsink  |   gst-buf -> cvMat -> gstbuf |  appsrc
> -> videoparse -> videoconvert ->
> xvimagesink
>
> I can save the image from the cvMat and the result is as I expect, however
> the image shown in xvimagesink is grayscale and constantly shifting upwards
> and to the left. (Best I could do on description there)
>
> <http://gstreamer-devel.966125.n4.nabble.com/file/n4681701/xvimagesink.png>
> <http://gstreamer-devel.966125.n4.nabble.com/file/n4681701/dewarped.png>
>
> The code where I suspect the problem is:
> (conv is the Mat shown in the attached image)
> //get outputize & allocate mem block
> 	gint outSize = conv.cols * conv.rows * inBpp;
> 	GstMemory *outMem = gst_allocator_alloc(NULL, outSize, NULL);	
>
> 	//assign frame data to mem
> 	GstMapInfo outMap;
> 	if(!gst_memory_map(outMem, &outMap, GST_MAP_WRITE))
> 	{
> 		g_printerr("could not map outMem\n");
> 		return;
> 	}
>
> 	memcpy(outMap.data, conv.data, outMap.size);
>
> 	gst_memory_unmap(outMem, &outMap);
>
> 	GstBuffer *outbuf;
> 	outbuf = gst_buffer_new();
>
> 	gst_buffer_insert_memory(outbuf, -1,outMem);
>
> 	GstVideoMeta *outmeta = new GstVideoMeta();
> 	outmeta = gst_buffer_add_video_meta(outbuf,GST_VIDEO_FRAME_FLAG_NONE,
> GST_VIDEO_FORMAT_RGB, conv.cols, conv.rows );
>
> 	//set timestamp values
> 	GST_BUFFER_DURATION(outbuf) = (GstClockTime)40000000;
> 	GST_BUFFER_DTS(outbuf) = GST_CLOCK_TIME_NONE;
> 	GST_BUFFER_PTS(outbuf) = timestamp;
> 	timestamp += GST_BUFFER_DURATION(outbuf);
>
> 	GST_BUFFER_FLAG_SET(outbuf, GST_BUFFER_FLAG_LIVE);
>
> 	//ref buffer to give copy to appsrc
> 	gst_buffer_ref(outbuf);
>
> 	GstFlowReturn ret;
> 	ret = gst_app_src_push_buffer((GstAppSrc*)asrc, outbuf);
> 	if(ret != GST_FLOW_OK)
> 	{
> 		g_printerr("could not push buffer\n");
> 		g_printerr("ret enum: %i\n", ret);
> 	}
>
> 	//dec. ref count so that we can edit data on next run
> 	gst_buffer_unref(outbuf);
>
>
> I have tried adding extra conversion stages in my out-pipe but to no effect.
> Has anyone had experience with this before or is able to spot some rookie
> error I'm making?
> Thanks
> Brandon
>
>
>                          
>
>
>
>
> --
> View this message in context: http://gstreamer-devel.966125.n4.nabble.com/OpenCv-Mat-to-GstBuffer-appsrc-possible-buffer-underflow-tp4681701.html
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