I.MX6 Framebuffer Overlay

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i.MX6 offers hardware composition of 2 framebuffers for video output. Here are the instructions on how to use it.

Note: These instructions are only available on APF6 with 3.14 Freescale kernel (apf6legacy_defconfig)

Tools

• you will need to compile following tools:

$ cd target/demos/fb_alpha
$ ../../../buildroot/output/host/usr/bin/arm-linux-gnueabihf-gcc -o fb_alpha fb_alpha.c

• install fb_alpha on your board's rootfs

Instructions

• Display something on main Framebuffer (/dev/fb0), here the stream from an analog camera:

# modprobe adv7280_tvin
# modprobe mxc_v4l2_capture
# gst-launch-1.0 imxv4l2videosrc ! imxg2dvideosink &

• Then activate auxiliary Framebuffer (/dev/fb1):

# echo 0 > /sys/class/graphics/fb1/blank

• and put it some stuff on it:

# fb-test -f 1 &

• then you can set alpha/overlay parameters with fb_alpha tool:
  • here we move overlay to (200,200):

    # ./fb_alpha -x 200 -y 200

  • same but with no transparency:

    # ./fb_alpha -x 200 -y 200 -g 1 -a 255