Re: Video overlay on sabresd

[Marco Trillo <martri@arantia.com>]

Hi,

On 05/25/2015 11:27 AM, Nikolay Dimitrov wrote:
> Exactly. Regarding the MXCFB_SET_OVERLAY_POS - I was thinking this
> ioctl is related to X/Y position of the layer and not about the layers'
> Z-order (at least this is the impression I have looking at the mxcfb
> driver and imx lib code). Please correct me if I'm wrong, but I thing
> the Z-order of the BG/FG IPU layers is not programmable.

Issuing the MXCFB_SET_GBL_ALPHA or MXCFB_SET_LOC_ALPHA ioctls() at 
/dev/fb0 should cause the `fb0' layer to display atop the `fb1' or video 
layer, mixed according to the global or per-pixel alpha value. This is 
what the docs say (which is a bit confusing):

3.2.2 DP global alpha combination
To enable DP global alpha combination feature, we need to use fb ioctl 
MXCFB_SET_LOC_ALPHA [sic]. [...] By default, /dev/fb0 stands for the 
background frame buffer and /dev/fb2 stands for the foreground frame 
buffer [...] If the open file descriptor of /dev/fb0 is passed to this 
ioctl, the graphics plane of DP is set to the background plane, 
otherwise, the graphics plane is set to the foreground plane.
(from Freescale's "Image Processing Unit V3 (IPUV3) Library User's Guide")

After configuring the DP via these ioctls, you can then use the 
MXCFB_SET_CLR_KEY if you need to use color keying.

Kind regards
Marco