[Herman.Chen]

I guess RK3066 has/uses 2D accelerator (such as overlay and scaler) to show decoded frame on screen, correct?
I can see some references for /dev/rga and /dev/rk29-ipp in some libraries.

Yes, you are right. We use hardware rga to composite to final framebuffer directly and ipp is for deinterlace.

Hi Chen having this interface for XBMC like in RKPlayer and Direct to Display instead of memcpy would be indeed much more efficient, hope we can get to that point while still rendering Subtitles and GUI on top
I guess these strange rendering and kernel crashes @ 1080p in XBMC we are experiencing currently are coming from the GPU driver then, though why does it work to disable 1 core and get more stable playback (without any rendering issues, though still occasional crashes) ?

I guess nothing has changed for the now released RK3188 in terms of this GPU output buffer Limitation ?

PS: It's nice to see Rockchip being interested in helping out reaching a broader audience with their Hardware and filling demands

Mutual help and cooperation is good for each other Thanks for reply.
in RK libstagefright when Subtitles is required we use rga to make a copy of video frame and draw subtitles on it by cpu. Then the rga composite the video frame directly to linux framebuffer. These part of code is in hardware composer (hwc). GUI is another surface layer.
About the GPU driver we make some change to support video format GPU rendering. I am not familiar with this part, sorry.
RK3188 and RK3066 use the same GPU so they have a same output buffer limitaion.