NVBuffer (FD) to opencv Mat

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
6

Hi,
We don’t observe the issue by applying following patch to 13_multi_camera:

diff --git a/multimedia_api/ll_samples/samples/13_multi_camera/main.cpp b/multimedia_api/ll_samples/samples/13_multi_camera/main.cpp
index 49a9ab8..0613f0b 100644
--- a/multimedia_api/ll_samples/samples/13_multi_camera/main.cpp
+++ b/multimedia_api/ll_samples/samples/13_multi_camera/main.cpp
@@ -39,6 +39,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <opencv2/opencv.hpp>
+
 using namespace Argus;
 using namespace EGLStream;
 
@@ -259,7 +261,7 @@ bool ConsumerThread::threadInitialize()
     input_params.width = STREAM_SIZE.width();
     input_params.height = STREAM_SIZE.height();
     input_params.layout = NvBufferLayout_Pitch;
-    input_params.colorFormat = NvBufferColorFormat_NV12;
+    input_params.colorFormat = NvBufferColorFormat_ABGR32;
     input_params.nvbuf_tag = NvBufferTag_VIDEO_CONVERT;
 
     NvBufferCreateEx (&m_compositedFrame, &input_params);
@@ -333,8 +335,8 @@ bool ConsumerThread::threadExecute()
             if (!m_dmabufs[i])
             {
                 m_dmabufs[i] = iNativeBuffer->createNvBuffer(iEglOutputStreams[i]->getResolution(),
-                                                          NvBufferColorFormat_YUV420,
-                                                          NvBufferLayout_BlockLinear);
+                                                          NvBufferColorFormat_ABGR32,
+                                                          NvBufferLayout_Pitch);
                 if (!m_dmabufs[i])
                     CONSUMER_PRINT("\tFailed to create NvBuffer\n");
             }
@@ -349,7 +351,21 @@ bool ConsumerThread::threadExecute()
         {
             // Composite multiple input to one frame
             NvBufferComposite(m_dmabufs, m_compositedFrame, &m_compositeParam);
-            g_renderer->render(m_compositedFrame);
+            void *pdata = NULL;
+
+            NvBufferMemMap(m_compositedFrame, 0, NvBufferMem_Read, &pdata);
+            NvBufferMemSyncForCpu(m_compositedFrame, 0, &pdata);
+
+            cv::Mat imgbuf = cv::Mat(STREAM_SIZE.height(),
+                                     STREAM_SIZE.width(),
+                                     CV_8UC4, pdata);
+            cv::Mat display_img;
+            cvtColor(imgbuf, display_img, CV_RGBA2BGR);
+
+            NvBufferMemUnMap(m_compositedFrame, 0, &pdata);
+
+            cv::imshow("img", display_img);
+            cv::waitKey(1);
         }
         else
             g_renderer->render(m_dmabufs[0]);

Makefile:

+CPPFLAGS+=`pkg-config --cflags opencv`
+LDFLAGS+=`pkg-config --libs opencv`

Maybe certain parameters in NvBufferCompositeParams are not well configured in your implementation?

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