How to get access to the raw pixel data just before it's sent to the LVDS?

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How to get access to the raw pixel data just before it's sent to the LVDS?

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erictheis
Contributor I

We are using a Sabre board with an IMX.6dq. Apologies in advance: I'm a kernel guy but video is new to me.

We want to copy/capture the Android display contents in near real time, and copy/DMA them to our development device

(which is not a display). Similarly we want to be able to pull raw display images from our device and display them on the

Android display screen. We need to do this fast enough that we could run, say, a game on one device, transfer the screen

images using our device to a separate Andriod system, and display them there. We need to grab the frames fast enough/

display them fast enough that there's no obvious latency (to the degreee possible).

We have demo code which reads from the Android frame buffer /dev/fb0. However

1) it's pretty slow, and

2) it captures 'Android UI' graphics, but doesn't seem to see the game screen at all.

The idea is that we could:

- Discover the address of the IPU's output frame buffer,

- Hack the driver to DMA its active framebuffer contents to a buffer allocated for our device (or vice versa)

- Hack in some way to notify our driver when a framebuffer is made 'active' (is ready to display).

I'm thinking of adding an ioctl where we would pass the address of our device's buffer(s),

and possibly a callback so we could get notified when a buffer is made 'active' (being displayed).

I've been rummaging around in the code a good bit, but I'm pretty lost.

Suggestions? Pointers?

This is for a demo, so this doesn't need to be an industrial-strength solution. That's later.

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alejandrolozan1
NXP Employee
NXP Employee

Hi Eric,

Can you provide more details about the development device?

I will delve into this, but I need as much information as possible.

Best Regards,

Alejandro

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Wlodek_D_
Senior Contributor II

Dear Eric Theis,

Thank you for your post, however please consider moving it to the right community place (e.g. i.MX Community ) for better visibility.

For details please see general advice https://community.freescale.com/docs/DOC-99909

Thank you for using Freescale Community.

Regards,

Wlodek_D.

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