[H-GEN] dvds

[Paul Gearon]

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Mike Andrew wrote:
> On Thu, 13 Jan 2000, staeci at yahoo.com wrote:
> > >%_me is wanting to buy dvd drive to replace my aging 4x cdrom in my
> > linux box
> 
> there are NO problems directly replacing an IDE cd rom of any speed with a
> dvd. Linux treats it as an atapi-cdrom drive. Music and files (from cd's)
> work as before.
> 
> linux kernel 2.4 series due for release witll support dvd and my memory is
> that the  dev kernel s2.3.43+ ?? supports it (or is that usb)

Actually Jens Axboe has a 2.2.13 patch as well.  Check out 
http://www.kernel.dk

There's probably also a 2.2.14 patch, but I've been away on holidays, so
I haven't had a chance to check that yet.

> But, the issue for you is 4x. In my world that means it's connected to a
> sound card port. There, you have problems. No true ide device will work
> on that psuedo ide port, it's butchered.

That's an issue for an individual's machine.  Standard IDE works fine.

> The long answer for you is check first that your machine can accept another
> 'slave' device on your primary or secondary ide channels. If you have a
> 486, forget the whole excercise. That cpu will never have enough scrunch to
> process the mp3 and other signals from a dvd - rom.

The rule of thumb is that you require a minimum of a PII 350 to do
software DVD playback.

> There are of course, hardware dvd solutions to playing film and sound from
> them, involving the addition of a pci-card,  but you will get caught in a
> muddle as to whether linux will support that specific card.

As of yet there are NO hardware DVD playback options under Linux.  A
couple of companies have programmers trying to do it, but the biggest
problem they keep running up against is legal issues.  :o(  It's
progressing though.

As for software playback... the news is both good and bad.

<skip this if you aren't really into DVDs>

We have SOME playback capability now.  Unfortunately, it's mostly been
done for Matrox hardware (good for me of course, but not for others). 
There is some work for other video cards, but it's very limited.  Of
course, this sort of thing requires direct access to the hardware
framebuffers, so each card has to be coded for to get effective
playback.  Alan Cox and others are working on it though, so don't
despair!  :o)

As of 2nd Jan (I haven't had the opportunity to check since then), it is
possible to playback the first 20 minutes of a DVD with synchronised
sound.  There are VFS issues with going beyond that point, but it's
being worked on.

Someone's doing the "main menu" stuff in GTK, and ac3 sound decoding is
being improved all the time.  A lot of sound cards only handle 44KHz,
while DVDs have 48kHz.  We've been debating the best way to handle it,
as nobody has yet been willing to bite the bullet and do the full
oversampling/filtering code.  :-)

Now for the bad news.  The DVD consortium is currently dragging the
whole thing through the courts in California.  They really aren't happy
about DeCCS.  Personally their whole legal argument doesn't make sense,
but a good American laywer can get a court to announce that black is
white if there's money in it.  As a result, it may possibly be made
illegal to play a DVD under Linux.  (at least with Open Sourced code)

Fingers crossed.

-- 
Regards,
Paul

Paul Gearon
gearon at computer.org

Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum
immane
mittam.
(Translation from latin: "I have a catapult. Give me all the money, or I
will
fling an enormous rock at your head.")

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