hdmi framebuffer blending with alpha channel.

Hi, there,

I currently look for a solution to do video blending on HDMI port, I am using the latest L4T r21.4, which is running Ubuntu 14.04, and Ubuntu take control the frame buffer '/dev/fb1", which should bind to HDMI output, and the gstreamer come with “nv_omx_hdmi_videosink” plugins which can output whatever and anywhere on top of hdmi, so my idea is to disable Ubuntu’s X server and take control of frame buffer of HDMI, and stream data from v4l2 camera device using that framebuffer, other than that, we also need an overlay which can do alpha blending on top of the frame buffer, is Jetson provide any display or graphic device which can do such thing? thank you


IMO it would be less headaches and more reliable to implement this as your own fullscreen OpenGL application.

Hi, dusty_nv
Thanks for your idea, so do you have any suggest on using opengl, since we get the video data from a v4l2 camera device, which the format is YUV422, then we will feed the data into 2d image texture, then how about the blending layer? and also for the display, using glut? since it was YUV422 data, it seems that also need shader to do YUV->RGB colorspace transfer, right? could you confirm this design, or any better idea, since I am still a newbie to opengl, thanks.

You can use gstreamer with v4l2, nvvidconv, and openGL to do accelerated colorspace conversion, blending, and rendering.

Unsure about taking control of the framebuffer.

Here are some examples using gstreamer: