On Sat, Sep 21, 2002 at 08:05:45PM +0100, Mike wrote:
> Hi all,

Hello,

> I am putting together a set top box running
> linux for movies / web usage

Join the (big) crowd.

> and would
> like to hear what TV Out cards you have seen
> best results from under Linux.

Well, this is a contentious subject.  The reason being is that most
(all?) of the producers of TV-Out capable hardware are not providing
(all of) the programming specs on how to do TV-Out with their cards.

My conspiricy theory on this is that the producers of such hardware
want also want to be able to write DVD-playing software, as a sell for
their hardware.  In order to (manufacture and) sell these things in
the US, these producers are being hog-tied by the "Copyright
Consortium" (spearheaded by such organizations as the MPAA, RIAA,
etc.) into licensing the "DVD-decrypto-magic".  I suspect that such a
license carries a clause that the hardware producer will not do
anything to allow the easy copying of content and providing
programming specs for these TV-Out capable cards does just that.

> I have tried TV out using a low end Geforce 4
> with the nvidia binary drivers but there are some
> strange effects when watching movies through
> the TV Out (in scenes where there is a lot of
> action there is a split in the middle of the screen
> running horizontally, the upper half of the screen
> updates just before the bottom half and its very
> annoying!)

[ note the use of the word frame here is loose and not meant to
differentiate between frames and fields ]

It's called "tearing".  The reason is that the software/hardware is
not waiting until the vsync to update what is being displayed on the
television.  If the software/hardware waits until a frame is fully
displayed to the TV before changing it you do not see this effect.  If
it changes the frame while it is "half-drawn" to the TV, you end up
getting part of one frame and part of the following frame.

For the record, I am using a Matrox G400.  They are hard to come by
these days as they are no longer in production, and to the best of my
knowlege, Matrox are not producing drivers, nor publishing specs for
any of their newer cards.  They are also a bit expensive to just
display a video signal on a TV.

b.

-- 
Brian J. Murrell

Attachment: msg08972/pgp00000.pgp
Description: PGP signature

Reply via email to