Hi, My topic is heavly based on this post I’m currently trying to directly map a NvBuffer to a Opencv::GpuMat with NvBufferMemMap and NvBufferMemSyncForDevice on a Jetson TX2i. I took the main from the samples available in /usr/src/jetson_multimedia_api/ and took precisely the number 07. (Video c…

Hi. Thank you for your answer. I will verify if i can map a RGBA NvBuffer to a GpuMat. But for the cv::Mat part it’s working with only one plane (Y). So actually NvBuffer can map to a cv::Mat with YUV420 format. Why does GpuMat cannot do the same operation as cv::Mat ? ~S.

Hi, This would need other users to share experience. For OpenCV we are also learning from public posts. It looks like RGBA is a suitable format for hooking NvBuffer and OpenCV.

For NV12 format to GpuMat, you may have a look to this post: [image] Real-time CLAHE processing of video, framerate issue. Gstreamer + nvivafilter + OpenCV Jetson AGX Xavier I think I got it… Seems there is 256 bytes stride. This should be better (so far, not tested so muc…

Hi, Following up my recent post, i’ve successfully mapped a ABGR32 NvBuffer to a cv::Mat. But i still struggle to map my NvBuffer to a cv::cuda::GpuMat. It looks like my HW Buffer is not allocated on the device, i’m kinda flabbergasted ysyyork managed to download it to a Cpu mat. My question are s…

Hi, Thank you for your answer. I’m not trying or using anything related to the NV12 format. It looks like your solution is coming from a EGLImage produced by NvEGLImageFromFd. I cannot use this specific library. Still thank you for your time. ~S.

Hi, You would need to check why NvEGLImageFromFd() does not work properly in your environment. For mapping NvBuffer to cv::cuda::GpuMat, it is a must-call function.

Hi, Thank you for your answer. I’m currently working in a monitorless environnement. If i can recall correctly NvEGLImageFromFd() needs to be used with an egl_display if set to NULL the default egl_display is used. I also don’t have mesa-utils in my system. Do you know how can i work around with…

Hi, You may try to run this sample: Opencv gpu mat into GStreamer without downloading to cpu - #15 by DaneLLL If it can be run successfully, it should be fine to call the function in monitorless environment: egl_display = eglGetDisplay(EGL_DEFAULT_DISPLAY); eglInitialize(egl_display, NUL…

Hi, Thank you for your answer. I’m sorry to disappoint again, but here’s what i’m returning with commands from EGL library. /* Get default EGL display */ EGLDisplay egl_display; egl_display = eglGetDisplay(EGL_DEFAULT_DISPLAY); if (egl_display == EGL_NO_DISPLAY) printf("Failed to get EGL displa…

NvBuffer to OpenCV GpuMat. Does memory is directly accessible to the device?

Robotics & Edge Computing Jetson Systems Jetson TX2

DaneLLL September 7, 2022, 10:06am 3

Hi,
Only NvBuffer in RGBA format can be mapped to cv::Mat or cv::gpuMat. Please refer to the patches:
LibArgus EGLStream to nvivafilter - #14 by DaneLLL
NVBuffer (FD) to opencv Mat - #6 by DaneLLL

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NvBuffer to OpenCV GpuMat. Does memory is directly accessible to the device?

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