As mentioned in the past I got a new TV this year. It's an LG 32LCD2DB
with a native panel resolution of 1366x768. As well as the usual
SCART/component inputs it has VGA and HDMI. Currently my homebrew PVR
outputs to the TV via a full featured DVB card with onboard MPEG2
decoder, but this limits me to 720x576 output and a basic OSD. My
current box is a PIII-800 with a basic onboard SiS graphics chipset, so
it's not got the grunt to drive the TV directly itself. I'm thus on the
lookout for an upgrade.
Let's start with my constraints. I have a Silverstone LC-02 case. I'd
previously planned to upgrade to something bigger, but the discovery
that
LinITX can provide a variety of riser
cards to suit PCI-E/PCI as needed means I don't have to. The LC-02 will
take a MicroATX board and provide me with 2 slots, one of which is taken
up by the PCI DVB card. This box lives in my living room, so it needs to
be quiet - the current incarnation is a bit too loud but I believe
that's mainly due to using a standard heatsink+fan assembly, so I'm
hoping that something specifically designed to be quiet will be better.
An
lirc dongle and wireless keyboard/mouse are
already sorted.
I'd like to expand the use of the PVR to be a more general PC as well;
up until now it's just been a PVR, but being able to check email/IRC
would be nice, as would the ability to play games. Up until now I've run
VDR, which takes full advantage of the
MPEG2 decoder, but I'd like to give
MythTV a
decent try. All of this points to wanting more than just a HD hardware
MPEG2/MPEG4 decoder.
First lets start with the graphics chipset options. The contenders seem
to be ATI, Intel, nVidia and Via. From my reading ATI lack any form of
XvMC support in both
their Free and binary blob drivers, so we can discount them. nVidia have
support, but only in their binary drivers. The
Nouveau project have support
on their TODO list, but I can't see any sign of it yet. I'd really
rather avoid non-free drivers, so that leaves us with just Intel and
Via.
I really like the look of the
Intel
G965/X3000.
They've opened up their driver development and it seems to be quite
active from reading the Xorg mailing lists. However they don't have any
XvMC support;
Keith Packard on the xorg list
in February says "For media purposes, the current drivers aren't taking
full advantage of the hardware yet", though later on does say "XvMC is
on several of our lists; I don't know when someone will pick it up and
implement it". Unfortunately I get the feeling it's not a high priority;
I've seen/heard several comments about the fact that any processor
that'll get hooked up to this chipset will be more than fast enough to
cope without the assistance. That may be true, but I don't want my CPU
to be spending all its time trying to decode MPEG2 or MPEG4 at
1920x1080i while the GPU sits mostly unused. I'd much rather the GPU was
used to the full giving me spare CPU cycles, or perhaps the ability to
clock it a bit slower for common use cases, reducing power and heat.
I'm keeping Intel on my list because I hope they do get round to proper
support sooner rather than later. They've also talked about the fact the
GPU is programmable which would make it perfectly possible to add MPEG4
acceleration to the chipset; that would be pretty sweet.
It's a bit odd to end up with
Via on the list.
I mainly think of them as associated with MiniITX boards, but they do
also produce various motherboards for Intel/AMD CPUs with integrated
graphics. They managed to shoot themselves in the foot for a period of
time by limiting the maximum accelerated resolution to 1024x1024, but
recently they've released the
CX700M
/
P4M900
chipsets which appear to do 2048x2048. The
OpenChrome project have these up and
running to a basic level from what I can tell, but work on XvMC
support appears to be progressing with various patches and reports
flying about on
the list.
So currently it looks like Via has the best option (albeit through the
Free software community, rather than a concerted effort on their part),
while Intel has something that could be very appealing if the driver was
more complete.
The other factor is the CPU. 3 contenders this time;
AMD Intel and Via. My current PIII-800 is rated at
20.8W TDP. Modern processors are in general a lot hotter, but I need to
keep in mind that I'm looking for a quiet machine, and that the case
doesn't have a huge amount of room for big cooling systems. AMD's dual
core chips all start at 89W or more, though some of their single core
lower end CPUs are more like 67W. Of course the Intel graphics won't
work with it and I'm not 100% sure Via has a suitable Athlon chipset at
present either (the 2 I found were for Intel/Via). Intel's P4 offerings
aren't much better for power consumption, with many of the highest end
chips being over 100W. Core 2 Duo looks promising; 65W, so more than the
current CPU, but a lot more grunt. Via come out tops here; 20W for their
2GHz top end processor. However this is only single core and compares
poorly to the equivalent clock speed of Core 2 Duo.
A MiniITX board with a 2GHz C7 and a CX700M would probably make a fine
PVR, but I'm not convinced about there being enough grunt for anything
else. The Via chipsets appear to have more active in-progress support
for media acceleration, which suggests a P4M900 + Core 2 Duo. That's
contrasted with what looks to be the more powerful X3000, that actually
has a manufacturer who seems to want to get full Free support out there.
I'm probably a couple of months off actually making a decision; partly
because I want to watch how it all plays out in the hope that the Intel
chipset will get some more support, or that the Via chipset will be
proven to be reliable in operation. And assuming I do make a video
chipset/CPU decision I then get the joys of trying to find a motherboard
with DVI + SP/DIF. I know the G965 can do DVI out with an ADD2 card in
the PCI-E slot, but I don't know if the P4M900 supports the same thing.
I can't see an Intel MicroATX 965 board with SP/DIF out - there's an HD
audio header, but this doesn't seem to be a direct mapping. Can I get a
converter?
Try this patch: