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

[borisRobson]

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


                        




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