[vdr] Re: XServer (was: Games & etc on DVB)

[Matthias Biel <Matthias.Biel@web.de>]

Hi,

I agree with you, applications that need to transfer uncompressed image 
data in real time are not possible with the dvb-card. But this is 
different in the case of an X-Server. There is no need to transfer the 
complete frame buffer each time the image changes. Instead it's enough 
to transfer the rectangle containing the changed area and write it to a 
specific location of the dvb-cards framebuffer (in 8k chunks).

just my two cents,

Matthias

Matthias Mueller wrote:

>Hi,
>
>On Thu, Sep 19, 2002 at 06:15:54PM +0200, Martin Hoffmann wrote:
>  
>
>>>It would be too slow. Why not write driectly into the framebuffer of the
>>>dvb-card??
>>>      
>>>
>>Of course yes - but afaik the current driver (or maybe the hardware itself) 
>>does not allow to directly acces the buffer of the card !
>>    
>>
>According to a mail to the dvb-mailinglist, it's not possible:
>
>  
>
>>Peter Seyringer writes:
>>    
>>
>>>Is it posible with the new firmware to write direct in the framebuffer
>>>memory of the mpeg encoder. This would be a great future to implement
>>>some programs without any complicat algols (like converting them into 
>>>MPEG1 oder MPEG2). That makes it also posible to implement a WEB browser
>>>oder same games on the dvb-s card :).
>>>      
>>>
>
>  
>
>>No, sorry, nothing regarding this was improved in the new firmware.
>>
>>You are talking about 720x576x2x25 or about 20 MByte/s which 
>>you would need for transfering complete pictures in real-time.
>>I don't know how high we could really get. Right now we are happy
>>about 20 MBit/s.
>>It would also create over 5000 Interrupt/s on the PC side even 
>>if you use the full 8K dual ported RAM with buffer switching 
>>for transfers. 
>>
>>Ralp
>>    
>>
>
>Even if you could use 352x288, that would still need ~40MBit/s. I don't
>think this will be possible...
>
>Ciao,
>Matthias
>  
>