[vdr] Re: Re : Bitmap-format of OSD?

[Andreas Schultz <aschultz@cs.uni-magdeburg.de>]

On Monday 10 June 2002 09:58, Markus Schorer wrote:
> hi,
>
> > i do have the code for that, as i was playing with dxr3 support for vdr
> > myself. However, it is not that easy! SPU's have only 4 colors and vdr's
> > main menu needs more. I belive that the best way to go for the dxr3 cards
> > is to implement the main menu not as overlay, but to encode it in MPEG1
> > with a static background and use OSD (SPU in that case) only for the osd
> > parts (channel display, progress bar).
>
> but as far as i know, even vdr has the 4-color limitation on it's menu.
> it does use multiple windows with different color-spaces to display
> more colors though. this should be possible with multiple spu-streams
> with different color-luts too.

The DVB card can have multiple OSD windows with independant color tables. 
SPU's are a different story, there can only be one active SPU at any time! 
thera are two color table, one for the normal SPU and one for a rectangle 
highlight area within that SPU. The highlight area is not a seperate bitmap, 
it's just a set of four differen colors for the area. Tricks like overlaying 
multiple windows to get the desired effect are therefor not possible. Also, 
using a highligh area for the more colorfull spots is very limited, due the 
color scheme used by vdr (e.g. there are four button == 4 color -- plus you 
need one color for the text within the button, and background does count for 
one color)

> i once had another idea:
> get the iframes from the currently playing video stream and overlay
> the osd data on these images (and display this as i-frames only).
> i think this should result in a quite similar effect to the way
> it is displayed now, without using too much cpu.

You would first have to decode the full frame, overlay it and reencode the 
frame as MPEG (1 or 2). This certainly takes more CPU power that desirable. 
It certainly is a possibility for fast systems, but we need a fallback 
solution for low end systems.

Have fun

   Andreas

-- 
Andreas Schultz <aschultz@cs.uni-magdeburg.de>
Student of computer science

"In accordance with plans for Linux OS world domination
      infiltration of governments is vital (:-))."