Intel GMA graphics - any good for hi-def? 1920 x 1080 @ 50/60hz

[Keith Packard]

On Wed, 2007-02-21 at 06:31 +0000, Stroller wrote:
> Hi there,
> 
> I'm about to start putting together a MythTV system which I'd like to  
> be capable of playing back hi-def (1080i/p) video, and I'd prefer to  
> use an Intel graphics card (but I'll settle for Intel on-board  
> graphics hardware;) because of the open nature of their drivers.

The X3000 doesn't have built-in component video outputs, so you'll need
to drive the screen with DVI (which you probably want to do anyway). For
this, you'll either want to buy a BTX mother board that has the DVI
built-in, or get an ADD2 DVI output card (for about USD 20-30). I'm
fairly happy with the BTX boards we've gotten; the large external CPU
fan means they're much quieter than any ATX system I have here, but of
course BTX cases are not exactly commonplace.

> Unfortunately, nVidia graphics cards are very popular on the MythTV  
> mailing list, and I haven't encountered any users there who are  
> happily using Intel graphics. I think I've read posts by people who  
> had trouble using older Intel graphics chipsets, but not many who've  
> tried and not the latest generation of Intel graphics chips, so I'm  
> not really able to get the best feedback from that list.

For media purposes, the current drivers aren't taking full advantage of
the hardware yet. It does provide Xv, but not the XvMC addition which
moves motion compensation from CPU to graphics processor. A fast
processor can keep up with the motion compentation computation, but
doing that in the graphics processor would be preferred.

From what I've heard, H.264 video is not compatible with XvMC
acceleration; if this is true, then some HD content won't be accelerated
in this fashion on nVidia cards either. I'm still learning what all of
the various HD distribution mechanisms are using for compression
schemes, perhaps XvMC is useful for enough of them to remain important.

A few people are also looking at what it would take to do H.264
acceleration, perhaps at a slightly higher point in the video decoding
stack as well; the X3000 can perform effectively all of H.264, so we
should be able to easily add iDCT and maybe even huffman decoding to
reduce the load on the CPU even further.

If XvMC support would make the X3000 more usable for lots of people, it
would be quite reasonable to add it to the driver. I haven't estimated
how hard it would be, I would certainly encourage people interested in
doing this to go explore the current driver to see what might be
possible.

> I believe that the X3000 can do hardware graphics acceleration, but  
> I'm not clear what the driver support is like for that?

As this hardware is brand new, the driver remains in active development,
and it is supported actively both by Intel and other developers. I'd
certainly like to add support for pretty much any generally useful
feature, but there's only so much time in a day and everyone has their
own list of things they're working on. XvMC is on several of our lists;
I don't know when someone will pick it up and implement it.

> Can anyone give me some feel-good vibes about buying this hardware?
> 
> I'm presently struggling to find a board that features the X3000 & an  
> onboard DVI port (not to mention the 6 x SATA, 3 x PCI, 3 x PCIe that  
> I'd prefer).

Intel makes ATX boards without DVI and BTX boards with DVI. However, you
can add DVI to an ATX board with an ADD2 card that pipes video over the
wires that make up the PCI-E bus and then out a DVI connector. I've used
both styles and they work fine.

Note that to drive 1920x1080 over the DVI connector will require either
the modesetting branch of the intel driver or 915resolution to reprogram
the modeline appropriately.

-- 
keith.packard at intel.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
URL: <http://lists.x.org/archives/xorg/attachments/20070220/e65121bc/attachment.pgp>