[vdr] Re: Some ideas of memorycalculation

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Torsten Kunkel wrote:
> 
> Hi,
> 
> first, don't hurt me if I've mixed something up :)
> A few days ago, two vdr-runners were eating and discussing about the
> possibilities of vdr, and this idea was born:
> 
> The problem for high-res-osd is the ram of the dvb-card, this ram is
> limited (I'm using an imaginary number of 12 "blocks" for better
> visualisation in this post).

In fact the av7110 based FF DVB cards have only 7 such "block" (which are
called "windows").

> With this memory, you could make an display like:
> 
> ####
> ####
> ####
> 
> but also
> 
> ######
> ######
> 
> or even
> 
> ###########
> 
> but there is never the possibility to get the osd greater than 3x4.
> 
> But what about splitting this limited memory?
> 
> +---------+
> |#       #|
> |# ## ## #|
> |#       #|
> +---------+
> This are 10 Blocks, together less than the avayable memory, so the
> other 2 blocks could be used for addressing where this blocks should
> start.

You can place the 7 available windows at any positions.
However, the area between them will just be whatever the video
signal is currently showing.

Note, though, that beginning with VDR 1.3.7 these can no longer
overlap or be stacked. VDR 1.3.7 will see the OSD area as one big,
32 bpp area by default, and a particular implementation of the
OSD and "skin" can split the total area into several smaller areas
with different bpp and color palettes.

> The question for us is, if such an fragmentation is possible.
> The advantage would be great, you could use small icons of
> highres-areas and huge areas of for example 2bit-color.
> With this mix, you could fill the complete tv-screen with icons, the
> user would think, the osd has grown, but in real, the osd is just
> splitted.
> 
> Does anyone know if this theory is possible?

Well, the total amount of OSD memory on the FF DVB cards is about 80KB.
There's not too much "hires" stuff you can do if you want to cover
the entire screen...

Klaus


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