A minimalist Myth box

suzyj · Post by **suzyj** » Thu Jun 19, 2008 2:44 pm

Here's the first photo of the mythtv machine I'm putting together:

It's based on a Via EN15000G motherboard, with fan removed. I'm using a Hitachi 500GB 2.5" SATA drive for storage, and a Hauppauge Nova-T-500 dual DVB tuner card, on a riser to keep the height down. Power is via a PicoPSU, using an XP Power ACS60US12 60W open-frame SMPS for the 12V. Power consumption is around 27W idle (at the wall) and 32-35W when simultaneously watching and recording video.

I'm cooling the whole thing with a single 80mm Nexus fan. The lid (which is yet to be made) will have vent holes in the right hand side, so air will have to pass through the motherboard heatsink before escaping the box. The case is home-made, from 1.6mm aluminium sheet. There's space for a second 2.5" hard drive under the tuner card, and I've put mounting points for a larger power supply should I want to run a thirstier motherboard in the future.

The whole thing is 430mm wide (standard hifi gear width), by 260mm deep, by 50mm tall.

On the to do list:

Boards for the power push button and front USB socket.
A fan controller.
A lid.
Feet.
A front panel.
Grommets for the hard drive (it's the noisiest 2.5" drive I've ever heard, but still a lot quieter than a 3.5")

MoJo · Post by **MoJo** » Thu Jun 19, 2008 4:25 pm

I'd love to know if you can get H.264 decoding to work on this board. It's supposed to support it, but there is no software support at all for Windows and only an old hacked version of mplayer for Linux.

matt_garman · Post by **matt_garman** » Fri Jun 20, 2008 4:52 am

MoJo wrote:I'd love to know if you can get H.264 decoding to work on this board. It's supposed to support it, but there is no software support at all for Windows and only an old hacked version of mplayer for Linux.

Seconded. I'd like to know more about the software side of things in general. Does it record/play HD TV? Or just SD?

That's a really nice looking build (more pics please

). If you can get acceptable HD and h.264 performance from that board/CPU for such little power draw, I say awesome.

Monkeh16 · Post by **Monkeh16** » Fri Jun 20, 2008 9:35 am

matt_garman wrote:
MoJo wrote:I'd love to know if you can get H.264 decoding to work on this board. It's supposed to support it, but there is no software support at all for Windows and only an old hacked version of mplayer for Linux.
Seconded. I'd like to know more about the software side of things in general. Does it record/play HD TV? Or just SD?

With hardware support, the software can handle HD (or at least, it damn well should be able to.. but I recall issues with relatively low quality SD streams not so long ago. myth isn't too well written). I'm not sure if there are any HD streams a Nova card can pick up.

MoJo · Post by **MoJo** » Fri Jun 20, 2008 11:50 am

The issue is that there is no support for the hardware except that old hacked version of mplayer. No drivers, no codecs, nothing. Apparently MythTV can use the old version of mplayer but it's not much of a solution, especially for those of us who don't run Linux.

suzyj · Post by **suzyj** » Fri Jun 20, 2008 2:45 pm

I've been unable to get the openchrome drivers to work, so all the decoding's done by the CPU. It can keep up fine with MPEG2 SD. I don't transcode SD content - just dump it to disk as MPEG2. The Nova card uses practically no CPU resources, so I can capture two HD streams easily. The issue with HD is playing them. There's very little HD content that's not available in SD, so I plan run a transcoding job on them as a low priority process to get HD content. The board can't do that in real time though.

I've tried to make the box reasonably flexible, so that when the new atom motherboards come out, I can swap the Via for an atom.

That said, the only reason I can see for playing HD is being able to brag about it. SD is perfectly good enough for me. The box does SD quite well, and with wonderfully low power draw.

MoJo · Post by **MoJo** » Sat Jun 21, 2008 7:39 am

An XBOX with 750MHz Celeron can do Xvid up to about 1024x960 without problems. Some H.264 at SD resolution is okay, but most of the stuff available for download is not.

Maybe the new EPIA boards with PCI-e could be okay with a Radeon 38xx but the older ones only have PCI

suzyj · Post by **suzyj** » Tue Jul 01, 2008 6:04 pm

Some more photos.

The overall layout. I swapped the 80mm Nexus for a Noctua case fan. The hard drive under the tuner card is a 160GB 2.5" SATA, which holds the OS and my FLACs. The other hard drive is a 500GB 2.5" SATA, which is just for video.

The power supply (bottom left) is a 12V 60W open-frame switcher. I use a PicoPSU 120 to convert that to 5V and 3V3.

I've left some space at the back for a better DAC. There's space next to the fan for a fan controller as well.

I added some heatsinking to the bottom of the board, which helps dissipate heat a little. Basically I stuck an aluminium block to the bottom of the case with thermally conductive paste, then stuck a Bergquist Gap Pad conformable gap filling thermal pad to the underside of the PCB, beneath the CPU and Northbridge.

Here's the air inlet. The Noctua fan pressurises the case. It's mounted with a silicon gasket, so it doesn't transfer vibrations to the case.

The exhaust vent is in the lid, arranged so that air must flow through the motherboard heatsink and past the PicoPSU to escape. It works quite well. With the fan running at 5V, the CPU temperature comes up to 42 degrees C.

I also added sound deadening material to the underside of the lid. It's very quiet, but not totally silent. The noise from the crappy onboard DAC is at about the same level (once it's made it through my HiFi system) as the noise from the fan and hard drives).

Here's a view from the front. It'll have a proper front panel, with properly mounted power pushbutton and front USB port when it's finished.

Here it is in-situ, as it were. Once the front panel is made, it'll look boring, just like the amplifier it's sitting on.

that Linux guy · Post by **that Linux guy** » Tue Jul 01, 2008 7:04 pm

Your new mini rig looks really, really nice. Tell me about that case though... did you make that yourself, or is it a stripped down case from something else? So you haven't had any issues running Linux on it? I've been looking at building a set up a bit like yours, and I can't get enough of seeing how others have built their own MiniITX Myth boxes. No issues with software or performance?

suzyj · Post by **suzyj** » Tue Jul 01, 2008 10:26 pm

The case is home-made. I folded it from 1.6mm aluminium sheet. I guess you could adapt a rack mount case to house stuff, but by the time you've cut all that metal, you really might as well start with a clean sheet. The advantage with doing it from scratch is that all the holes can be easily punched before folding.

Getting Ubuntu and mythtv to work properly on the Via board has been challenging, but not impossible by any means.

I'm yet to get the openchrome drivers to work properly, so the mpeg2 decode is currently being done in software (about 20-30% cpu utilisation for SD content). I haven't given up on that yet.

My main push software-wise at the moment is to get it to automatically shutdown and wakeup to record programs. I think by doing that I can get the average power consumption down from 27 odd Watts to around 10-12, or better if I can improve the shutdown consumption.

that Linux guy · Post by **that Linux guy** » Wed Jul 02, 2008 12:42 am

suzyj wrote:The case is home-made. I folded it from 1.6mm aluminium sheet. I guess you could adapt a rack mount case to house stuff, but by the time you've cut all that metal, you really might as well start with a clean sheet. The advantage with doing it from scratch is that all the holes can be easily punched before folding.

Getting Ubuntu and mythtv to work properly on the Via board has been challenging, but not impossible by any means.

I'm yet to get the openchrome drivers to work properly, so the mpeg2 decode is currently being done in software (about 20-30% cpu utilisation for SD content). I haven't given up on that yet.

My main push software-wise at the moment is to get it to automatically shutdown and wakeup to record programs. I think by doing that I can get the average power consumption down from 27 odd Watts to around 10-12, or better if I can improve the shutdown consumption.

Awesome job with the case. I've been wanting to try something like this myself, someday. The grocery business isn't the mose lucritive thing. I assume you spot welded the tabs together for the main floor and walls, right? I couldn't quite tell by the pics. I know the lid was simply a U shaped piece, secured with screws...

As for Ubuntu and MythTV, what version of Ubuntu are you using? Do you need a full desktop environment (Gnome with all the fixin's)? You could probably run a base install of Debian etch, and only set up Xserver, Gstreamer plugins, and MythTV. It wouldn't be too difficult, at least not in theory. I haven't tried such a project myself, as the girlfriend doesn't go so well for a PC in the Living room, no matter how much like stereo equiptment I make it appear. (SHHH. I'll just sneak one in

)

I've heard a lot of people complaining about Openchrome drivers giving problems on these Via EPIA boards. Have you read <a href="https://help.ubuntu.com/community/OpenChrome">this</a>?

How deep are you trying to get it to shutdown? You can't have it completely shutdown, but I'm sure if you mess with some /etc/init.d/rc file and change some init settings, you can get it to go into a deep sleep until your favorite show <cough>Dexter</cough> comes on.

I have a Mountain Dew here, so I raise it to your new rig. It looks awesome and I can't wait to hear more about it. Keep us updated, as I'm sure I'm not the only one who's really diggin' what you're doing.

-Andrew