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Re: apple dvd pccard

On Wed, 2005-04-20 at 09:20 -0500, vinai wrote:
> On Wed, 20 Apr 2005, Dean Hamstead wrote:
> > sadly the mpeg decoder on the ati cards in imac dv's
> > (and my ibook dual usb) are unsupported
> >
> > thats the sole reason my old imac dv runs osx
> >
> > man id be willing to throw cash at someone to
> > reverse engineer it. pity ben is a busy man as
> > it is. someone clone him.
> Well, that's a little bit of a different situation.  On the older Mac
> Powerbooks, with 64-bit ATI graphics chips, there was a dedicated
> MPEG-2 hardware decoder, either a PCMCIA card, or a chip on the laptop
> motherboard.  I don't know if the 64-bit chip lacked the horsepower,
> or just basicfunctionality, to play MPEG-2 streams at the appropriate
> frame rate, but additional hardware was needed.

Yah, and it's not simple to make it work because you need both to have a
driver for that chip, and to have a proper capture/overlay driver for
the mach64 as the output of that decoder is a digital video stream
(4:2:2 afaik) that is routed to the input of the mach64 chip.

> On your macs, you most likely have at least 128-bit graphics hardware
> (the lombard was the last laptop to have 64-bit, and either the old
> Beige G3 tower or Blue and White G3 tower was the last desktop to come
> with 64-bit).  In 128-bit chips and above, MPEG-2 decoding is done in
> the video card hardware.  I don't think ATI ever published info about
> this function for any of their cards, which is why you need a machine
> with enough CPU power to decompress DVDs.
> However, when I did have my lombard (G3 400), I thought either Xine,
> mplayer, or VideoLan (most likely the last one, as that's what I've
> been using the most) would play DVDs _JUST_ at the level of
> "watchability" (i.e. if there was a lot of rapid action or scene
> changes, video would stutter.  But for a less variable scene, it'd
> be fine).  And that was quite a few years ago, on OS X...
> Having a G4 helps, as I think the writers of some of these packages
> have been able to utilize Altivec to assist with the MPEG-2 decoding.
> But this is where things stand (AFAIK ;-)
> cheers
> vinai
Benjamin Herrenschmidt <benh@kernel.crashing.org>

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