HowTo: Mac Mini '09 + MythTV as Media Center, DVR

(I am reposting this from an entry on my website).

Signal Source: HDHomeRun

For signal, I bought a DB-4 antenna from Antennas Direct and an HDHomeRun. I installed the antenna in my attic, and since my house is already wired with Cat5E just dropped the antenna wire through the wall next to the ethernet jack, where I could put the HDHomeRun. Once I had it on the network, I tested it with the HDHomeRun-config-gui.app that they supply.

Computer Hardware: Mac Mini and Upgrades

I started with a base model 2009 Mac Mini (1GB/80GB) with a bluetooth keyboard and mouse. I bought a 320GB 7200 RPM drive (Seagate ST9320421AS) that has good reviews, plus a 2GB DDR3 RAM stick from Crucial.

I followed online instructions for opening up the Mini for the install. They were mostly good, but missed out on telling you about a few things
A high-quality (sharp-edged) plastic spatula can crack open the outer case while leaving absolutely no marks. Doing this is time-consuming and difficult but possible.
Once you have the outer case off, the tape off, and the antennas unmounted, it is very easy to accidentally unplug the bluetooth antenna cable when lifting the drive frame up off the motherboard. The antenna wire is easily reconnected but takes a surprising amount of force to get the connector back on that little coax mount.
When you replace the old HD you will have to unstick the temperature sensor and a couple of sound dampers. There's enough glue on them that they'll stick right back on to the new drive. **Remember where (on the old drive) these items were so that you can replace them on the new drive!
You can test run your mini with the outer case still off. That way you can tell if anything is loose or whatever before risking having to crack it again.

Computer Configuration

Once the new hard drive was installed, I hooked up a monitor and booted the system from the install disks (this is slightly easier using a USB rather than bluetooth keyboard and mouse by the way). First, I went to the system diagnostics (About This Mac...) to check that the RAM had been found. Then I started Disk Utility, and partitioned the drive into 80GB for the OS and 220GB for PVR recordings and other big files. The point of partitioning is twofold:
Make sure I can never hose the system by having recordings eat all available space
Keep stuff that requires no backups all in one place.

Though I have a NAS (ReadyNAS NV+) I did not want to use it to store recordings, since its throughput is unlikely to match the local 7200RPM drive.
Software Setup

Once the drive was partitioned, I put the original drive in a USB enclosure, and used Disk Utility to restore from the old drive onto the 80GB partition. Doing this is much faster than making and restoring from a Time Machine backup. I could then boot the machine, and run Software Update to get everything up to date. Then I told iTunes where to find music on my NAS, and copied some favorite photos into iPhoto.
Power Management

I configured the computer to never sleep, and never sleep the display or hard drive either. I also set it up to restart after a power failure.
DVR Software: MythTV

Backend

Next, it was time to install the MythTV backend. Though MythTV is mostly a Linux project, it does work on OSX with a few quirks. The main resource for this is the wiki page, and I had already experimented somewhat using my Mac Pro. Using the pointers on that page, I downloaded the latest SVN nightly build from Sniderpad.com (I haven't actually noticed big differences between this and the 0.21-fixes release). I downloaded the backend and frontend then unpacked the Myth* executables into my Applications folder.
MythTV Prerequisite: MySQL

I downloaded the OSX package for MySQL 5.0.77 and then I installed MySQL. It comes with a Preference Pane to turn it off and on, and can be set to automatically start up, which is what you want.
Partitioning and Files

On the Recordings partition, I created a folder named MythTV, with 4 subfolders entitled LiveTV, Groups, Default and Backups. I also created an account at SchedulesDirect to get TV listings. I created directory for mythtv logfiles, as /var/log/myth and I changed ownership of this directory to the GUI user rather than root so that Myth could write to it.
To set up the backend, I launched Terminal.app and ran the database commands from the wiki page. First I chose a password (mythtv is a good choice if you are not worried about security). Then I ran MythTV-Setup.app.

A quick note on running the Myth* apps: when you are first starting out, it is best to run these from the command line (in Terminal.app) rather than by double-clicking the icons. That way, you can see any useful error messages that would otherwise just disappear from sight. The way to do this is to start a new Terminal window, then run, for example,
/Applications/MythBackend/MythTV-Setup.app/Contents/MacOS/MythTV-Setup

I ran through the setup application, telling it what my database password was and that I have an HDHomeRun (no need to specify the IP unless you have more than one unit). For each of the HDHomeRun's 2 tuners, I had to tell the setup program about my SchedulesDirect account. I also had to let it scan for channels, but that was necessary to do on only one tuner. (As a side note, channel scanning seemed fine on the Mini but it choked on the Mac Pro, probably due to threading issues. I put a note on the wiki page about that).

I told setup to go ahead and mark commercials during recording. I also told it which directories to put files in (the ones on the Recordings partition), and that mythfilldatabase should log to a file in /var/log/myth.

Once setup was done, I could run mythfilldatabase (which I again elected to do from the command line) and then start the backend.
Frontend

Now I could set up the frontend. I started the front end and told it the database password in the setup menu, and that I wanted it to automatically skip commercials. I tested LiveTV and recordings. I did not bother to set up any of the other features or plugins since I planned to get all that from Plex.

Automatic Startup

Once I was happy with MythTV's workings (and it actually took a few iterations -- you're getting the cleaned up version here), I made a launchd configuration file to automatically start mythbackend on boot, or at any time the backend crashes. You only want to do this after everything is really truly working because otherwise launchd may eat half your CPU just restarting mythbackend over and over, and it is fairly complicated to stop that behavior without a reboot. To enforce autostartup, I put a file named MythBackend.plist in /Library/LaunchDaemons, with the following content:





Disabled

KeepAlive

Label
MythBackend
ProgramArguments

/Applications/MythBackend/MythBackend.app/Contents/MacOS/MythBackend
-l
/var/log/myth/MythBackend

UserName
dvr


Please note that the UserName variable should be set to the GUI user name.
Plex

Now I could do the easy part -- set up Plex. I downloaded the latest version, installed it, and set up MythFrontend as an available external app. I also told it where to find movies, photos and home videos on my NAS and installed a couple of plugins. I cannot say enough about how awesome Plex is, so I'll let you discover it for yourself. I set up the user account so that it would automatically start Plex at login. Then I unplugged the Mini and brought it to my AV system, plugging it into a 100MB/sec segment of my network.

Final Connections

Using a mini-DVI to HDMI adapter I bought at Monoprice, I connected my Samsung PN-63B550 plasma display using HDMI input #2, and used a TOSLink optical cable to connect from the dual-use output jack of the Mini to an optical input of my Onkyo DS-777 AV receiver. Booting the Mini got me a nice display on the plasma right away. The Mac autodetected the plasma and set its video appropriately, choosing to overscan by default. The overscan is a little too much and hides the top menubar but I don't mind since I'm usually using Plex or Myth. You can turn off overscan in System Preferences->Display. Does anyone know if this Samsung has a "Just scan" option?

Monitoring

The best way to monitor the MythTV backend is by using Console.app. It's provided by Apple, and is lightweight with a nice interface. Just point it at the appropriate files in /var/log/myth.
Results

Both sound and video are smooth and good-looking to my untrained ear and eye. When MythBackend is recording and marking commercials, CPU usage is about 100-125% and MythFrontend playback gets untolerably jumpy in 1080i (720p is acceptable). However, full-res Plex playback is still just fine while MythBackend is working this hard (obviously because Plex is using CoreVideo and the GPU).
Plex's slideshows are nice (they launch as a screensaver), along with its ability to play iTunes playlists with the visualizer. I'm thrilled with the Myth ability to autoskip commercials. As a computer monitor the Samsung is acceptable for short periods but it would give you eyestrain to try to use it for a whole day.
To Do:

Remote Buddy (maybe using a Wii controller?)
Try to set up commercial flagging on the Mac Pro without making it have to stay on all the time

Problems:

At one point after an upgrade, MythBackend could not see the MySQL database. Since launchd was eating 70% CPU by launching it over and over, I had to remove MythBackend.plist, reboot, launch mythbackend manually, quit mythbackend, restore MythBackend.plist, and reboot again. The problem disappeared.
With the Apple Remote, MythFrontend views each button press as two presses. This makes it impossible to select half the items on any list with an even number of choices.
This revision: April 8, 2009
Contact: htpc(at)boonstra.org

I use the frontend for watching TV -- I have it set up as an "Application" in Plex. But for everything else Plex is much nicer. So MythTV is exclusively for watching broadcast TV (delayed or live), and Plex runs the rest of the media center.

By the way, the forum software here ate the formatting and links on the guide, so you might find it more readable on the original website. (I'm not shilling here -- I don't make any money off it, not even google ads).

Thanks for the comments.

To clarify, I run both the frontend and backend on the Mac Mini -- the Mac Pro is not a practical place to run anything that needs high availability. I prototyped on it, and also would like to have Myth find it for flagging at those times it happens to be available. But that's the extent to which I can allow the Pro to be involved.



Good advice. The upgrade was not to Myth but rather to the OS. I'm still occasionally running afoul of this startup issue -- clearly an opportunity to practice my launchd-fu. I did consider setting up yet another box as you advise, solely to run the Backend, but for now I don't see the need, nor do I want to pay the electric bills.


Plex seems to actually exit and set itself to restart after MythFrontend is finished -- a neat trick. So it's not taking any cpu cycles at all. MythBackend and the flagging are, of course, eating plenty of cycles when necessary. This doesn't really bug me since I can just watch something else via Plex when this is happening.

I had set options so that commercial flagging of shows could begin immediately. Last night I watched the box do this (having recorded Office and 30 Rock in succession). It went to 200% CPU (100% on each) which makes me think that the recording process is probably contending with the flagging so much that it could be missing frames.

Based on this, I would not recommend setting instant flagging start on a Mac Mini. I'm going to keep looking for how I might set up flagging servers on other CPUs without them having to be available 24/7. Does anyone have hints?

I jumped straight to Plex and Myth. I really, really love Plex so FrontRow was right out. Also I'm kind of an open source guy, with decent database, sysadmin and programming chops, so I wasn't terribly afraid of the notorious Myth complexity. My brother-in-law may try the EyeTV route...I'll relay his impressions if he does.

I will say that if you are willing to dedicate a (MythBuntu) Linux machine somewhere to being your backend, then MythTV setup is fairly easy.

I'll check on the job count -- that's a good idea. Does the job count affect flagging only? I still want to be able to record two programs simultaneously.

I hadn't considered this but you remind me that I do think MythFillDatabase was running as well. I'm actually a little mystified (mythtified?) why it chose to run in the evening rather than at 4AM or something. I could swear that the XML from SD tells it to do the next grab at a low-traffic hour.

If commflagging is nicing itself, then that would explain why 200% CPU usage didn't seem to be crushing the usability of the machine at the time. So maybe I can let it continue, at least if ensure the right nice level.

I should probably test it....my assumption is that commercial skipping won't work if I do this.

I tried this out, but had no success. Plex managed to find the uPnP server from my readyNAS, but could not find one from Myth. I tried just forcing the URL but then Plex just said it couldn't see the server.

Does Myth automatically start its uPnP server and publish recorded shows? The documentation is very sketchy on this topic.

Yes, I went through the backend setup, and did not find any kind of enabling flag. I don't have the firewall on, so I'm a little lost as to why Plex can't see Myth. Given I want the skipping (and, like you, don't trust flagging 100%) it's probably not something I'll pursue any further.

Right now, I'm still fighting with the launchd-based autolaunch of the backend. It appears to happen in some way that keeps it from finding the Mysql DB, even as launchd tries to start it over and over.

I might move the launchd plist from the system over to the GUI user.

Update: I just upgraded to MythTV 0.22. To do this, I decided to work with a development snapshot. I built my own -- the osxpackager.pl works very well -- but I see that thesniderpad.com now has these available as well.

Once I upgraded, I turned off the old backend using

since I have the backend running from launchd with a KeepAlive directive. I saved all the old executables in a backup directory, and moved the new executables into their place.


After that, I did some backups of the database and such, which are obviously optional, and then ran MythTV-Setup.app. For this purpose,

is very easy to use.


MythTV-Setup upgrades the database automatically for you. I also went ahead and downloaded channel icons, something I had never done before when the app was uglier and more confusing. Then I added some requested directories to the Storage Groups.

Once that was done, I ran the frontend, which asked to do few more automatic database upgrades. I let it do that, ad then checked that everything works. It all seems great (and finally works properly with my Apple Remote!). The new UI is gorgeous.

I didn't even know about this AC3 passthrough feature, so no - I don't know if it is fixed. Is it something that is desirable for North American TV shows? Please let us all know what you find out.

I'm with you on that. Apparently there was some effort in this direction, as seen in this ticket but nothing has been done for years.

That's interesting. I had hoped that CoreVideo would be automatically offloading to the GPU, at least eventually. Is that not the case?