[linux-dvb] Re: HDTV & DVB / VDR (dscaler ..)

[Emil Naepflein <Emil.Naepflein@philosys.de>]

On Thu, 10 Jan 2002 15:23:31 +0100 (CET), <mocm@convergence.de> wrote:

> I think people are not aware that the DVB-s card also has a
> video4linux device that can give you the decoded video output via DMA.
> You can scale the picture, change the brightness etc. .
> How do you think xawtv displays the picture?
> So, why would you need a bt848/878 card?
> Or what do you want to do? What do you mean by descaler?

Does the MPEG stream transmitted bei DVB contain the interlace flag
identifying fields that belong together just like on DVD?

For film this normally helps to combine the both interlaced fields that
belong together into one non-interlaced frame. For video you have to use
some more intelligent algorithm to avoid the zick-zack lines, because
her the source is really interlaced.

I assume the video4linux device just places the interlaced image into
the frame buffer. This looks just awfull with programs like kvdr on a
large screen (I have a beamer). Currently the image from the S-video
feed through my scaler, which scales it to 1024x768 anamorph, looks much
better then any progressive image from the graphic card, even the scaler
cannot do 2:2 pulldown. The scaling to a higher resolution smooth the
edges at the cost of sharpness. 

BTW, the Reply-To: line in the header is wrong again.

Emil


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