The Mac mini as a digital video recorder

This text describes how I turned a Mac mini into a digital video recorder. Actually, the same procedure could easily be adapted to any other Linux-capable computer — the only Mac mini-specific parts are the prerequisites below, and the configuring of the Mac mini remote control.

The prerequisites are:

Slackware on the Mac mini. Other distros will work just as well, but you'll have to improvise some steps since my assumptions are based on the installation and boot procedures for Slackware/Slamd64.
TV Output on a Linux Mac mini. Describes how you configure the analog TV-out capabilities of the Mac mini in Xorg 7.3. Only PAL is covered so far, some adjustments of the video geometry and timing signals will be necessary for NTSC.

You don't of course need TV Output in order to just record video, but the rest of this text will assume that the Mac mini will also be used for viewing video in full-screen mode on some TV-like device.

Install video capturing hardware and Linux driver

I use a several years old version of a Hauppauge WinTV-PVR-USB2 device, which is a TV tuner and MPEG2 encoder that is connected via the USB bus. Before my Mac mini came along, the same device was attached to a Microsoft Xbox running Linux, which had the Hauppauge device encoding all the time (even while nothing is being recorded) because of driver issues in the primitive userspace driver I was using. As of April 2008 the device has been encoding constantly for more than four years, with occasional breaks only a few times per year for rebooting the Xbox. So this Hauppauge hardware has been very reliable.
Until August 3, 2008, when a thunderstorm zapped it, together with the Mac mini. Both are now replaced, and the new PVR-USB2 device is faster, less expensive, and brews better coffee than the old one. And it has an IR Blaster! Note: Hauppauge pays me way too little for plugging their product like this...

If you have some other capturing device, you're on your own for now, but you might want to skim through the rest of this page anyway since it also contains some general tips that may be useful.

The driver to use for the PVR-USB2 device under a 2.6+ kernel is Mike Isely's pvrusb2 driver, which is included in the official Linux kernel source. To get it working, do the following:

Install the firmware. Follow the instructions under the label Firmware extraction and installation on the web page http://www.isely.net/pvrusb2/setup.html. It is also a very good idea to read all the information on that page before you plunge ahead. Hopefully you won't need it all because things should Just Work™ really. But it's a good idea anyway. Note: Slackware looks for firmware in /lib/firmware.
Do modprobe pvrusb2 with the device connected. The device /dev/video0 should appear. If you are attaching more than one video capturing device, the first one will be called video0, the second one video1, etc. If you don't find any devices, go back to the previous step and read all the information on the driver setup page.
Add yourself to the group "video" in /etc/group so you can access the video device, and then place the following script in /lib/udev so that the sysfs interface will be available for everyone in the group "video":
```
#!/bin/sh
GROUP=video
CLASSDIR=/sys/class/pvrusb2
if [ "$ACTION" = "add" -a -d $CLASSDIR ]; then
    GLOB=$CLASSDIR/*/
    chgrp -R $GROUP $GLOB
    find $GLOB -perm -u+w -print | xargs chmod g+w
fi
```
The above script can also be downloaded as rc.video. Activate it by appending , RUN+="rc.video" to the line for v4l/video in the file /etc/udev/rules.d/40-video.rules (don't forget that initial little comma).

Install and configure LIRC

LIRC is the de-facto Linux standard interface for infrared and other types of remote controls. I have never been able to get along very well with LIRC, and in fact I think LIRC sucks really bad for several reasons. But until something better replaces LIRC, it's still the most portable option for remote controls in Linux.

Ideally, you should download and install the latest stable LIRC release from http://www.lirc.org. However, when I tried lirc-0.8.3 it didn't compile due to incompatibilites with the 2.6.26 kernel, so a more successful approach is to download from CVS: http://www.lirc.org/cvs.html. Then do ./autogen.sh to create the configure script for the CVS version.

For the Apple IR remote, configure like this:

./configure --with-moduledir=/lib/modules/`uname -r`/misc --with-x --with-driver=macmini --with-major=61 --with-port=none --with-irq=none

For the Hauppauge remote, configure like this:

./configure --with-moduledir=/lib/modules/`uname -r`/misc --with-x --with-driver=hauppauge --with-major=61 --with-port=none --with-irq=none

You want both? Sorry, not possible unless you choose all available drivers, including a bunch that won't compile unless you reconfigure your kernel.

Before you compile, you may want to apply my LIRC disksaver patch which makes lircd terminate when it gets a read error whenever the device is disconnected. The LIRC default behaviour is to loop uncontrollably and fill up the entire disk with repetitions of the same error message.
```
patch -p0 < lircd-disksaver.patch
```
Then compile and install:
```
make
make install
  
```

Configure the device and start the daemon:

Copy one of the files lircd.conf-APPLEIR, lircd.conf-HAUPPAUGE34 or lircd.conf-HAUPPAUGE45 to /etc/lircd.conf. The HAUPPAUGE remote is recommended if you want to use GLOTV as your DVR software (see below). The two versions of the HAUPPAUGE lircd.conf correspond to the 34-button and the 45-button versions of the remote control. Click on one of the pictures to the right to download the corresponding HAUPPAUGE lircd.conf. APPLEIR is not yet supported by GLOTV since it has too few buttons.

Change permissions on the LIRC socket:

chgrp video /dev/lircd
chmod g+w /dev/lircd

Put the following in your /etc/rc.d/rc.local:

if [ -x /usr/local/sbin/lircd ]; then
  modprobe lirc_dev
  modprobe lirc_i2c
  /usr/local/sbin/lircd
fi

If you have one of the latest pvrusb2 devices (the ones with the IR Blaster) you will get two lirc devices: /dev/lirc0 and /dev/lirc1. One of them works, the other one is an emulated device that only works with earlier hardware. To avoid confusion, you can disable the non-working device by inserting the following in /etc/modprobe.d/dvr:
```
options pvrusb2 ir_mode=0
```
See this explanation by Mike Isely for further details.

A replacement for LIRC would be a blessing. I am seriously tempted to write a simple and easy remote control reader myself, but that will have to wait for a bit.

Install DVR software

Install GLOTV, my own lightweight DVR system. Other possible choices are MythTV or Freevo.

Enable autologin for runlevel 4

Replace the Slackware script for runlevel 4, /etc/rc.d/rc.4, with the autologin script that is available here. Edit the script and change the definition of $X11USER to the user that you want autologin for. But first, make sure the user exists and has a useful ~/.xinitrc.
Make LILO boot into runlevel 4 by default. Leave the Slackware inittab default alone (it's runlevel 3). Instead add the boot option "4" to the default LILO image in /etc/lilo.conf. Look here for such a lilo.conf. After boot, use the commands telinit 3 and telinit 4 to switch between runlevels 3 and 4 when needed, i.e. for maintenance work and debugging.