[vdr] Re: [linux-dvb] OT: a rant regarding DVB-C cards

[Dennis Noordsij <dennis.noordsij@wiral.com>]

Hi Juha,

One possible argument in favour of full featured cards, is that you don't 
*have* to use the tv-out to still be able to use the mpeg2 decoding 
capabilities.

So you could set up a cheap video card with tv-out, and write a VDR driver 
which is not much more than an xvideo overlay window (fullscreen), grabbing 
decoded frames from the video4linux device (just as if it were grabbing video 
with a normal analogue capture card) and blit it to the xvideo window. 
Trivial to overlay the OSD, and you won't see the video corruption when 
having the OSD on because it is added afterwards and not by the ARM.

If you have 2 cards for example, you can have picture-in-picture by simply 
grabbing from 2 video4linux devices and blitting them in whichever way you 
want, requiring very little CPU. 

Then you are of course free to play games using the TV as well, and play divx 
or whatever movies without having to transcode. DVD's use the mpeg2 decoder 
of course. Picture-in-picture with nelonen in the corner while watching a DVD 
would be possible for example.

Some cards are very expensive (i.e. Hauppauge one at Verkkokauppa.com :-) and 
only offer composite, but the Siemens for example has composite, s-video and 
RGB. Depends on the card. 

CI modules is a tricky area, at this point it's easier to decide what you 
intend to watch, what you need, and then (if possible) conclude which card / 
driver will support that.

Not much choice in Finland unfortunately, I ordered mine from a friendly guy 
in Germany :-) 

By the way, these are Siemens cards, advertised as only able to do QAM-64, but 
with some undocumented (read, lucky :)) register values it will happily do 
QAM-128 also. The actual chip used for the decoding (ves1820) can do up to 
QAM-256, so I am not sure why Siemens decided to change their minds and not 
support > QAM-64. Mine work just fine with HTV. Needs finetuning though (of 
several values used by the cards hardware) which is pretty much 
trial-and-error. But at least it will work.

Cheers,
Dennis








-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe vdr" as subject.