Xavier tegra_multimedia_api opencv

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
1

hi，
I want to know how to get the image data frome tegra_multimedia_api samples ,and convert the image date to opencv Mat.

// Acquire a frame.
            UniqueObj<Frame> frame(iFrameConsumers[i]->acquireFrame());
            IFrame *iFrame = interface_cast<IFrame>(frame);
            if (!iFrame)
                break;

            // Get the IImageNativeBuffer extension interface.
            NV::IImageNativeBuffer *iNativeBuffer =
                interface_cast<NV::IImageNativeBuffer>(iFrame->getImage());
            if (!iNativeBuffer)
                ORIGINATE_ERROR("IImageNativeBuffer not supported by Image.");

thess are the code to get the image ,but how to get the format and size of the image ,then conver to opencv Mat?

2

Hi,
Please refer to this patch

3

hi,
ok, thank you !

4

hi，
I have patched the file 09_camera_jpeg_capture.txt,but get the error below,then I manually modify the code.

cat main.cpp.rej
--- samples/09_camera_jpeg_capture/main.cpp
+++ samples/09_camera_jpeg_capture/main.cpp
@@ -144,8 +146,8 @@ bool ConsumerThread::threadExecute()
         if (m_dmabuf == -1)
         {
             m_dmabuf = iNativeBuffer->createNvBuffer(iStream->getResolution(),
-                                                     NvBufferColorFormat_YUV420,
-                                                     NvBufferLayout_BlockLinear);
+                                                     NvBufferColorFormat_ABGR32,
+                                                     NvBufferLayout_Pitch);
             if (m_dmabuf == -1)
                 CONSUMER_PRINT("\tFailed to create NvBuffer\n");
         }
@@ -350,7 +355,6 @@ static bool execute(NvEglRenderer *renderer)
         ORIGINATE_ERROR("Failed to get IOutputStreamSettings interface");

     iStreamSettings->setPixelFormat(PIXEL_FMT_YCbCr_420_888);
-    iStreamSettings->setEGLDisplay(renderer->getEGLDisplay());
     iStreamSettings->setResolution(PREVIEW_SIZE);
     UniqueObj<OutputStream> previewStream(iCaptureSession->createOutputStream(streamSettings.get()));
     if (DO_JPEG_ENCODE) {

when I execute the program ，it will occur the error below

nvidia@nvidia-desktop:/usr/src/tegra_multimedia_api/samples/09_camera_jpeg_capture$ ./camera_jpeg_capture
nvbuf_utils: Could not get EGL display connection
PRODUCER: Creating output stream
PRODUCER: Launching consumer thread
CONSUMER: Waiting until producer is connected...
CONSUMER: Waiting until producer is connected...
PRODUCER: Available Sensor modes :
PRODUCER: [0] W=1928 H=1208
PRODUCER: Starting repeat capture requests.
CONSUMER: Producer has connected; continuing.
CONSUMER: Producer has connected; continuing.
Segmentation fault (core dumped)
5

Hi,
Please run with ‘–disable-jpg’.
The JPEG encoder does not expect RGBA buffers so you need to disable it.
Also please try ‘export DISPLAY=:1’ and check if you can get information via ‘xrandr’.