Debian on Digimatrix

2004-Oct-27

Introduction

We have a Digimatrix hooked up to our high-definition television. We use it for a number of things:

MythTV and Freevo vs. KDE

This sounds like a MythTV box, right? I tried MythTV, and Freevo, and while I was impressed with how pretty they were, I just couldn’t get them working quite right.

MythTV gave a blank screen trying to watch or record TV, with no useful error messages, and try as I might I just couldn’t figure out what the problem was. After spending three days on it I gave up.

Freevo had its own problems; I don’t remember exactly what they were now. I do remember feeling like Freevo was held together with bailing wire and chewing gum, while MythTV had a much more polished and easy-to-use feel to it.

Neither of them worked well out of the box with the Digimatrix remote control.

In the end, I decided it’d be easier for everybody if we just used KDE. It lets me bind actions to the key sequences the remote control sends out, and for most TV-type activities the remote does enough to move around in Xine and Konqueror. The x2x program allows us to use our laptops to control things over the wireless network, when the remote doesn’t suffice. The Unix at utility and a little shell script lets us schedule TV recordings with more ease than a VCR.

Best of all, there’s no meta-information filed away in some obscure database layout. Everything is a file somewhere and can be manipulated with Konqueror or the shell.

This turns out to be a very workable setup.

Installing the base system

I had to install the testing (etch) installation CD for it to have a driver for the SiS 900 10/100 network card. Installation went smoothly enough. Everything is detected at boot time except:

I installed the following additional packages to help me administer the machine:

# apt-get install less zile screen ssh strace sudo ntp ntpdate

Web server

Waldorf needed to run a web server to host photo albums.

# apt-get install mathopd stunnel4 php4-cgi rssh
# apt-get install netpbm jhead exiftran libjpeg-mmx-progs libjpeg-progs

I won’t detail my web server configuration here, since that’s unique to me.

X

# apt-get install x-window-system

To my surprise this brought in x.org. I run an HDTV over DVI, so to get full screen, I had to change the configuration as follows:

Section "Device"
        Identifier      "Generic Video Card"
        Driver          "sis"
        Option          "ForceCRT1Type" "DVI-D"
EndSection

Section "Monitor"
        Identifier      "Generic Monitor"
        Option          "DPMS"
        HorizSync       30-65
        VertRefresh     30-60
        ModeLine "720p" 74.160 1280 1352 1392 1648 697 725 730 750 
EndSection

I also had to add “720p” to the Modes of the Display subsection of Screen.

You may notice I only have 697 pixels vertically. That’s because my TV puts about 23 lines in the “overscan”, preventing me from seeing my KDE toolbar. I haven’t yet found a way to recenter the screen, this just chops off the bottom. As a hack, I put empty KDE toolbars on the top, left, and right borders. This keeps windows inside the viewable area.

KDE

I like KDE. I’ve tried MythTV and Freevo and found it’s just easier to run KDE and occasionally use a mouse and keyboard. The only thing we don’t get is a snazzy interface to recording TV shows, but we don’t tend to want to do that very often. I may work on a web interface to XML-TV listings later on.

# apt-get install kde kdm

I don’t know if this is typical or not, but Debian’s KDE went on without asking me a single question. Kudos to the packagers.

Sound

# apt-get install alsa-base alsa-utils

We use the Digimatrix’s S/PDIF output (isn’t it lame that it comes out the front?). I know from a previous installation that if you just use the defaults, you need to reboot between playing 2-channel audio and using Xine’s pass-through option to play a 7.1-channel DVD. I’m sure it has something to do with the sound card resetting something or other. The solution seems to be having ALSA multiplex audio, and while I don’t get why this works, work it does.

I put the following into /etc/asound.conf:

pcm.asus-hw {
    type hw
    card 0
}

pcm.!default {
    type plug
    slave.pcm "asus"
}

pcm.asus {
    type dmix
    ipc_key 1234
    slave {
        pcm "hw:0,0"
        period_time 0
        period_size 1024
        buffer_size 4096
        rate 48000
    }
}

ctl.asus-hw {
    type hw
    card 0
}

A decent desktop

At this point I was able to browse the web and play music using KDE’s “JuK”:http://developer.kde.org/~wheeler/juk.html, so I took a break to dance around the living room with my 1-year-old daughter as ABBA sang to us.

Playing DVDs

I like kaffeine, mostly because it’s part of KDE and I’m a purist. It can play all sorts of movies and even has a nice startup screen that allows you to type in numbers for various actions (play from playlist, play DVD, etc.).

# apt-get install kaffeine

DVD drive speed

Linux does not use DMA on IDE devices when it boots up, you have to turn that on yourself. I’m not sure what the reason is for this, probably compatibility with some ancient thing that blows up if you attempt DMA. In any case, turning on DMA will allows your DVD drive to keep up with the data on the DVD.

# apt-get install hdparm

To turn on DMA, I put the following at the end of /etc/hdparm.conf. While I was at it, I turned ot DMA for the hard drive too.

/dev/dvd {
	dma = on
}

/dev/hda {
	dma = on
}

Try a DVD

At this point I was able to watch DVDs, so I did. I watched the first DVD of the first season of Buffy, which turned out to be a terrible idea since it’s pretty dark and not very high quality. I played around with the gamma settings in the KDE configuration tool, and set my gamma at 1.25. Then I adjusted the brightness, contrast, and saturation of Kaffeine, and got what I think is a pretty nice-looking configuration.

The remote control

What good is a home theater system if you have to get up off your butt to press buttons? This is America, man! I want to be able to eat cheez-doodles and watch porn all night without having my feet hit the floor, ever.

The keyboard thingy

My Digimatrix came with this IR receiver thingy that goes in between the keyboard and the keyboard port on the Digimatrix. It synthesizes keypresses in response to your remote. Pretty slick! This is good enough for most things, and for a long time I just bound remote keystrokes to do certain things in KDE applications, and to certain actions in Xine.

lirc

lirc is the Linux Infra-Red Control system. It provides a standard interface to various IR recievers and remote controls, and supplies events to whatever wants to listen to it. KDE has a module to listen to it, so I figured I’d give it a go.

# apt-get install kdelirc

Unfortunately, lirc 0.7 (the version in debian testing and unstable) does not compile on Linux 2.6.12 and newer, so I had to install from source code.