How to acquire frames out of EGLStreamKHR and map to NvBuffer for use in NvVideoEncoder

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
1

Hi,

I have a CUDA-based EGLStream producer that needs to connect to a consumer based on NvVideoEncoder. The CUDA producer connects to a EGLStreamKHR that will be provided to the encoder consumer for it to also connect to, but I cannot figure out how to acquire frames out of the EGLStreamKHR stream, and map them to an NvBuffer.

The only examples showing consumers using a EGLStreamKHR are based on GL textures, which seems to have specific calls for mapping EGL frames from the stream to GL and acquiring them, e.g. eglStreamConsumerGLTextureExternalKHR() and eglStreamConsumerAcquireKHR().

The “EGL_KHR_stream - Khronos Group” spec mentions acquiring frames via eglStreamConsumerAcquireAttribKHR(), but is not clear on how to get the actual pointer to the frame. The 10_camera_recording example is helpful, but only covers how to map between Argus::Buffer and NvBuffer, while I am looking for a more generic solution that deals with EGLStreamKHR directly.

Please note that I realize that I can use Gstreamer via nveglstreamsrc to consume the frames, however I would prefer to use NvVideoEncoder directly. Can anyone please explain how to acquire a frame out of an EGLStreamKHR stream and map it to an NvBuffer, so it can be encoded by NvVideoEncoder?

2

Hi,
It is impossible to map the buffer directly. Need one memcpy through CUDA.
You need to create NvBuffer and get CUDA pointer of destination by calling:

NvEGLImageFromFd();
cuGraphicsEGLRegisterImage();
cuGraphicsResourceGetMappedEglFrame();

,use CUDA consumer APIs to get CUDA pointer of source:

cuEGLStreamConsumerAcquireFrame();
cuGraphicsResourceGetMappedEglFrame();

, and copy source(CUDA consumer) to destination(NvBuffer).