[SDL] How to accelerate

[Gabriele Greco]

wgkun at mailst.xjtu.edu.cn wrote:
> Hello!
> I have to program for a video system under linux
> which gathers video data from CCD camera and displays.I
> have completed the driver for gathering card. But because
>  I'm a newbie to video programming, I have some difficults.
> The system needs display 25-50 frames per second.Each frame can be
> 1024*1024 or 512*512 with 8 bits per pixel.The video data
> are all grayscale.A friend introduced SDL to me.And I have
> made a test.Everything is ok but the display speed.
> Following are my main test codes:

Why not to draw directly to the video surface or make the video surface 
a sw surface and let SDL_UpdateRects() do the blit?

I think that having a video surface that is a HW surface and blitting a 
SW surface to it is always slower of both the previous solutions.

As pointed out is also a MUST that your full screen resolution is 8bit 
depth as your source datas. Maybe to get this to work correcly on X you 
should log as root and do export SDL_VIDEODRIVER=dga.

50fps should be quite easy to reach on 8bit depth 1024x1024 buffers on 
non-prehistoric hardware, just make sure there are no conversions, 8 -> 
16 and 8 -> 32 conversions are very expensive!

Bye,
  Gabry