Jul 16, 2007

Separating the MythTV Frontend from the Backend

The services of MythTV are divided into two major groups; the frontend and the backend. The frontend is the GUI that one sees when you are watching the content and choosing what to watch. The frontend has themes that change the look of the interface. The frontend also renders the video that is displayed which is not insignificant when it comes to high definition content. Some MythTV plug-ins are also a part of the frontend that extend functionality such as browsing weather or playing music. On the other side the MythTV backend is the brains behind the scenes. It interfaces with the MySQL database and the capture cards to schedule and record the content. The backend sends the data that the frontend displays and provides the schedule information that it has received from the selected data services company. See Zap2it article

The frontend and the backend typically run on the same computer in most setups I have seen and used. This makes the setup straight forward. MythTV has an excellent network code that allows the very efficient communication between the frontend and backend even on separate computers. This is put to the test with high definition content with a very high bit-rate but performs admirably on wired gigabit ethernet. I know what you are thinking with wi-fi but this is too much bandwidth for A/B/G wireless LAN when it comes to HD. Standard definition does work with my wireless. There are reasons and advantages to separating the frontend from the backend. The most obvious reason is to divide and conquer the tasks. Commercial flagging and compression to Xvid on the backend will not make your HD content playback choppy if they are on different computers.

In my case I wanted to have a central server that was located in my office running the backend. This was most convenient for my cable drops in my house and it allowed me to use this computer as my main office computer as it was the most up to date computer. I wanted to watch the MythTV in my office so I also put a frontend on it but I also wanted to watch the content on my main TV in the living room. I made a frontend computer with relatively good components that were as silent as possible. I used an overclocked AMD FX-55 with an Artic Cooling CPU fan that was very quiet. I used a Nvidia 7600GS video card that was passively cooled for no noise. I used the bare minimum of hard drive capacity because nothing was recorded on this computer. I used an off brand case with large 120 mm fans to be as silent and efficient as possible. Finally I put a creative sound blaster Audigy sound card to have good sound. One other thing I did was to not plug in any of the blue LED's that would flash and turn on with the case because I did not want the distraction of these watching TV. The simple power on / off LED was all I needed to see. I could make all of these decisions based on the specialized function of the computer being a frontend only. One thing this really helped with was cable clutter. I could have a single power cord, audio cable, network cable, and video cable coming out of the frontend computer which helped make the system look very clean. No coax from the wall and splitters opon splitters to the multiple tuners etc.

The preparation for separating the frontend from the backend is making the MySQL database that MythTV uses accessible to the LAN.

sudo nano /etc/mysql/my.cnf

You need to comment out the bind-address line like so:

#bind-address =

Then you can restart your computer so that this new parameter is passed into the MySQL database as it initializes.

The frontend box is just a base install of Ubuntu 7.04 that has been fully updated. Instead of installing Mythtv from the application manager you search for mythtv-frontend. When you install this package all of the packages needed for just the frontend are installed.

Jul 7, 2007

Ultimate Mythtv Remote

I bought a Nokia N770 from the recent Woot.com offering. I had immediately envisioned a wireless remote scheduler for my Mythtv backend in the other room. Using Mythweb allows for one to schedule and manage the recordings on the Mythtv. If you have Mythtv just use the application manager in Ubuntu to search and install Mythweb. This install is insecure as in it allows anyone on the LAN to access and change your Mythtv recordings etc. Use on a private LAN or take some mesures to secure the accessibility.

Mythweb seems to be perfect for use with the Nokia's 800 x 480 native resolution. I just put the IP address of the computer with the \mythweb and load the webpage. This would presumably work just as well with Apple's new IPhone. I think the screen of the Nokia 770 is slightly more high resolution than the IPhone but it would work.

I also found an application that will stream video and audio to the Nokia 770 called GMyth

Jun 23, 2007

Making your PS3 into a HD Tivo

I have been doing some research on what else I can do with my HDHomerun and thought it would be perfect for use with the PS3 turning it into a HDTV recorder. Since the tuner lets you stream from the LAN without installing any drivers or PCI cards it will work with the PS3 as long as you have some software that will tune it. I got the idea from this blog PS3 USB Tuner where the person got some drivers for a USB capture device and used them to turn his PS3 into a PVR using Mythtv. This is possible because Sony has allowed alternate operating systems to be put on the PS3 like most flavors of Linux. The cell processor is a PowerPC core so most Linux versions are compatible that have a PPC version. I like the ease of use of Ubuntu so I found this guide to get Ubuntu on the PS3. Ubuntu on PS3

The next challenge is to install Mythtv on Ubuntu for PS3 either from source or pre-compiled binaries (which I don't know if they exist). Since the support for the HDHomerun is built into Mythtv that would be all that was needed to have a Mythtv Box. Given that the 80 GB drive is small under Linux you could just plug in a number of USB harddrives to store the HD content

The biggest problem in this setup is that Sony has not granted access to the video card in the PS3 for fears of open source developers making games for the PS3 that would edge Sony out of the game development. I find this funny given all the games that are out there for Linux are pretty basic. So what if I play Tron on the PS3; I don't think that will stop me from buying Madden. This means that the video card works but does not help with rendering. Without a good driver for the video card I have read that HD playback is choppy. This is a problem now but it may be resolved in the future by reverse engineering or Sony relenting. There is a petition to Sony to open up the Video Card Petition. This still does not leave out the PS3 from becoming a Mythtv backend that would be great for turning the HD into Divx or Xvid given the processing power of the Cell. Look at what the Cell processor is doing for research Folding at Home

Jun 20, 2007

Zap2it Labs Retires Sept 1st

Sad Sad Day

Posted from labs.Zap2it.com; Zap2It is the provider of free tv listings used in Mythtv extensively.


For several years we have offered a free TV listings service to hobbyists for their own personal, noncommercial use. In October of 2004 we posted here an open letter saying the future of Zap2it Labs was at risk because of certain growing misuses of the Zap2it Labs data. Unfortunately this misuse has continued and grown. These misuses, combined with other business factors have led to the decision to discontinue Zap2it Labs effective September 1, 2007.

We thank those users who have honored the terms of the agreement, and we suggest you consider the many TV listings options offered by the commercial licensees of TMS TV listings data.

If you would like to discuss how to license TV listings for commercial use, please let us know by e-mail (labs@zap2it.com) and include your company name, telephone number and the best time to reach you. We will respond to your inquiry as soon as possible.

We anticipate this decision will generate discussion and invite you to respond via the Zap2it Labs forum. We will do our best to respond to relevant questions posted on this forum in a timely manner.

Back in 2004 the Mythtv crowd would scrape xml data from free sources which is slow and inaccurate at times. Zap2It started offering free data service and this was very good! I want to somehow convince them to rethink things. I have submitted a comment in their forums offering a small monetary payment. This would have to be a tenth of what Tivo service offers or something in that range. Digg the article in My Digg Dugg links to raise an internet buzz about the issue so that they will reconsider or offer an alternative.

Jun 15, 2007

Installing Mythtv on Ubuntu 7.04

The last time I installed mythtv on Ubuntu I used Ubuntu 5.10 and compiled mythtv from source. My wife went away for the weekend when I started this project and when she came back she claimed I had not moved at all still configuring and installing. I have recently built a new media center pc so I had to reinstall Mythtv so I thought I would try the latest Ubuntu, Feisty Fawn. I could not believe how streamlined installing Mythtv had become.
The steps were to install Ubuntu from the live disk. I then set up the nvidia video card proprietary drivers. Then I opened up the Synaptic Package Manager and searched for "mythtv". Since I was setting up the frontend and the backend of Mythtv on the same computer, I selected mythtv package and installed. Synaptic first installed all of the prerequisites for Mythtv then installed mythtv. In the process a random password is given to you in a prompt that is the MySQL database password. Make note of this. It also puts this password in the setup for Mythtv. The backend setup is now an icon in the administration tab. You can start this setup and configure the Mythtv backend. The front end icon has been put under applications. This covers the installation which is essentially one step. Later I will go into the setup and configuration of Mythtv in a later article. This assumes you set up a regular desktop with the frontend and backend all on the same computer. See the howto from Ubuntu.

Jun 14, 2007

Getting HD over Cable with Vista Media Center

Getting your HD over the air is great. You don't have to pay anything to get a perfect picture on your HDTV. Depending on where you live, however, can mean you get poor reception. Weather can effect this signal. My neighbor has a problem with planes flying overhead on there way to landing at the airport! I bought the HDHomerun so that I could tune the unencrypted local HD channels that most providers do not scramble called clear QAM. I had basic cable already but did not want to pay extra for digital cable, and extra for other HD channels.
I now wanted to use Vista Media Center to record the channels. Vista is setup only to work with over-the-air HD so there is a little work to be done mapping the QAM channels to the ATSC channels so you can watch these new channels and get program guide data. Someone has made this an easier task by making a remaping GUI. You can download this here. You can unzip this into the C:\Program Files\Silicon Dust\HDHomerun directory. You then right-click on the QAMmapper.exe and pick run as administrator.

You pick the options of MCE and Full scan and you should see what HD channels you can pick up. I got the five major networks and checked them. Then you can assign virtual channels and physical channels. In order to get the guide to work you have to choose these two channels to be the same as the ATSC channels that Media Center has for you area. You can open an XML filed called ATSCChannels.xml in C:\ProgramData\Microsoft\eHome\EPG\prefs and find these virtual and physical channels if you have already scanned for HD channels in your area. Then you save the remap file and go to Documents\QAM Mapper and copy the atscprefs.xml that you just made to the prefs directory above.
Now you can manually setup your channels and scan for digital channels and should find the new QAM channels as if they were ATSC channels. This will then assign guide data to the channels and you should be able to watch and record them.

Jun 13, 2007

How to split your cable for all of those tuners

So your are building a monster media center with 4 tuners at least (thats 2 analog and 2 digital). You start splitting the cable with cheap splitters and wonder why your picture is horrible. In the case of tuning high definition over cable (Clear QAM), the picture stutters and breaks up and analog tv starts to look like you are using an antenna again. You need a distribution amplifier. This is basically a powered splitter that adds back some of the amplitude to the signal that you lost by splitting.

The catch comes if you want to put your cable modem behind this distribution amplifier or a digital cable box that does pay-per-view etc. Basically anything that needs communication back through the distribution amplifier needs a special type. This is called a bi-directional distribution amplifier. This allows that communication backwards through or more likely around that signal amplifier. I needed a 1 to 4 port to allow the HDhomerun (2 ports), my cable modem, and one analog tuner to all be plugged in at the same time. This worked well for my and my signal strength went back to a level that was good for all of the devices. I used an distribution amplifier that amplified the outgoing signal 8dB. Now I really need one in the box outside my house to split all of the inputs initially. I have seen some that do a version of power over ethernet with normal coax so I will look for one of these

Jun 12, 2007


I just received in the mail today a dual HD tuner called the HDhomerun from Silicon Dust. Link I use Linux, OS X, and Windows regularly and this solution works in all three environments. This has drivers to let it work with Vista Media Center, XP Media Center, and almost all of the 3rd party media centers like BeyondTV and MythTV. It uses VLC to stream if you are not using media center software to play the video. The box itself streams the HD signal over the network using UDP. This seems to work well in my own experience. Using this stream over wireless probably does not work well. The stream could take up to 20 Mb/s with both tuners going and would not do well streaming over the wireless ethernet. The Draft-N standard may change this though because of the increase in speed and performance. This dual tuner tunes HD from over-the-air and clear QAM (unencrypted digital cable). This may be one of the only ways to get clear QAM to Vista mediacenter. It works so well for me because I am running out of PCI slots on my computers and I have more than one mediacenter that can share this device. I will be posting some results and setup how-to's when I get some time to work on them

Jun 7, 2007

First Post - The TV

I wanted to start a blog to document all of the time and effort I have put forth in trying to get a media center to play and record all of my digital content. I am concerned about the broadcast flag so I wanted a system that completely ignores this. Linux is not the first OS that comes to mind when you think of multimedia playback but it turns out it is one of the best (with a couple of large caveats).
I have two media center computers recently built as well as two Samsung LCD TVs. The Samsung LCD TV's are perfect for this application because they have a good amount of connections as well as a VGA PC input that allows the full 1360x768 resolution be used.

I chose Ubuntu 7.04 for the OS because now this is the easiest way to install Mythtv. I would argue that it was much easier than Knoppmyth. I will post more about this setup in a later article.