Mythtv Users F A Q

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MythTV-Users Mailing List FAQ

CONTENTS

0. General List Questions

Q0.1: Why don�t we have a web based forum instead of this mailing list?

Q0.3: Should I use this list to find out where I can download TV shows/Films?

Q0.4: Anything else I should be aware of?

1. Basic MythTV Questions

Q1.1: Does MythTV run on Windows?

Q1.2: Does MythTV Run on OSX?

Q1.3: Which Linux distribution should I use?

Q1.3.1: How many capture cards do I need?

Q1.3.2: I have no interest in recording TV but I wish to use Myth as a music/video jukebox. Is this possible?

Q1.3.3: What are my options for connecting my computer to my TV?

Q1.4: How much disk space do I need?

Q1.5: I want a low power, silent computer to use as a frontend. What are my choices?

2. Configuration

Q2.1: When using live TV, why is there a delay between the moment I change the channel and the time the channel actually changes?

Q2.2: When viewing video there is an annoying blue border round the side of the screen. How do I get rid of it?

Q2.3: All my fonts look like they are the wrong sizes, how can I correct this?

Q2.4: I want to change the layout of my menus. What�s the best thing to do?

Q2.5: I�m using the TV-Out on the PVR 350 and X is larger than the screen. Parts of the desktop and Myth interface are cut off around the edges.

3. Links to useful information

ANSWERS


0. General List Questions

Q0.1: Why don�t we have a web based forum instead of this mailing list? This is a question that comes up on a regular basis, so unless you have a fascinating new insight into the matter it�s probably best not to bring it up. Basically there are pros and cons to both mailing lists and forums; however we have a mailing list because:

        • Many users prefer managing text only emails to the graphics adverts etc that are associated with forums.
        • Somebody would have to provide (i.e pay for) the bandwith and servers needed to run a forum.
        • Web based forums are difficult to archive.
        • Most email clients such as Thunderbird (and Gmail if you like web based mail) can be configured to make dealing with mailing lists surprisingly easy.

Q0.2: Should I use this list to find out where I can download TV shows/Films?

No. When you use MythTV you will find out that it is a very useful piece of software that can completely change the way you watch TV. It is not, however, a means to circumvent copyright and this list is no place to be asking for tips on how you should do so.

Q0.3: Anything else I should be aware of?

Firstly do a search of the mailing list archives before asking a question. There�s a wealth of information there. Also check out the MythTV Docs to see if your question is answered there. If you�re new to mailing lists in general try to learn a bit about netiquette from a site such as this one. Three good rules to follow are:

  1. Don�t top post. i.e. When replying to a message, put your reply below the quoted text from the original message. The reason for this is best summed up in the following piece of text which one of the list members uses as his sig:
     A: Because it messes up the order in which people normally read text.
     Q: Why is top-posting such a bad thing? 
    
     A: Top-posting.
     Q: What is the most annoying thing on usenet and in e-mail?
  
  2. When starting a new topic, don�t just reply to somebody else�s message and change the subject line. Doing this will retain the message headers, meaning that many people�s mail readers will interpret it as a reply to the original message.
  
  3. Try not to stray too far off topic. By all means tell us if you think something is of interest to the Myth Community, but requesting things like Gmail invites or informing us of the latest free Ipods.com offer is really not a good thing to do. 


1. Basic MythTV Questions

Q1.1: Does MythTV run on Windows?

The short answer is not really. The long answer is that there has been some work done to get basic frontend capability working on Windows by the win Myth people although the result is still fairly raw at this stage. Another potential avenue has been explored by those wishing to compile Myth on Windows by using cygwin, although as far as I�m aware there hasn�t been much success on this as of yet. If you do have a desire to watch Mythtv on a windows box then your best options are:

        • Run mythstream. This will allow you to stream video from you backend to a Windows Frontend, on which you can use mediaplayer etc to watch the video.
        • Use Knoppmyth. This will allow you to boot up your windows box into myhtfrontend in a way that won�t touch you hard drive (so when you take the CD out and restart you�ll go back into windows).
        • Use DS Myth. This is a series of direct show filters and applications, which enable the .nuv files created by MythTV to be played back on windows.

Q1.2: Does MythTV run on OSX?

The frontend does, the backend doesn�t.

Q1.3: Which Linux distribution should I use?

If you are already comfortable with Linux then it�s probably best sticking to the distribution you know best. If, however you�re a Linux novice then the best bet is to go with one of the following three options:

  1. Fedora. Jarod Wilson has written what is almost certainly the best guide to getting MythTV up and running and he�s done it based on Fedora. Find out more here.
  2. Knopp Myth. This is a version of Knoppix bundled with all of the stuff needed to get Myth up and running. Find out more here.
  3. Myth Dora. This is a stripped down version of Fedora along with some scripts which will install all the Myth stuff for you. Homepage is here.

Q1.4: How many capture cards do I need?

Basically you need one capture card for each program you wish to record at any given time, with live tv counting as a recording. The exception to his rule is the PVR 500 which contains two tuners and consequently counts as two capture cards. Examples:

        • With a single capture card you will be able to record a single program or watch live TV at any given time
        • With three capture cards you will be able to record up to two programs whilst still having the ability to watch live TV. You may then begin recording a third program but will then lose the ability to watch live TV.

Q1.5: I have no interest in recording Tv but I wish to use Myth as a music/video jukebox. Is this possible?

Yes. Myth has two plugins called MythMusic and MythVideo which can be used to handle video and audio libraries respectively. You will still have to install both Mythfrontend and Myth Backend, however Myth will work perfectly well without any capture cards installed

Q1.6: What are my options for connecting my computer to my TV?

Ok firstly I�m not really going to touch upon High Def here because it�s something I know little about. Secondly a full description of how to get perfect TV out is beyond the scope of this how to so I�ll just stick with the basics. If you�re really interested, however, go to the mythtv-users mailing list archive and search for posts by Cory Papenfuss. He explains it better than I ever could. Anyway your options are:

1.TV out on a graphics card.

Lots of graphics cards come with a TV out these days, usually in the form of an S-Video out which can then be converted to SCART if you live in Europe. The main piece of advice is to ensure that the graphic card you thinking of has Linux drivers that support the TV out functionality (until very recently some ATi cards had problems with this). If you�ve got a free choice, the best way to go is probably with an Nvidia based card, on the grounds that they have good Linux support and they�re used by many of the developers. If noise is important to you then try and get one without a fan.

2.TV out on the Hauppauge PVR 350.

Unlike all the other Hauppauge cards, the PVR 350 includes an S-Video out socket on the back of the card. The big advantage of using this is that the quality of the picture you get form the PVR 350 is generally regarded as being the best available. The bad news is that the PVR 350 doesn�t have any Open GL support, so if MythGame is going to be a large part of your life, this route probably isn�t for you.

3.A Scan converter

This is a single box, which converts the VGA signal from your video card into NTSC/PAL/SECAM for your TV. This has the advantage of working with any graphics card that has drivers available, and is relatively simple.

4. A homebrew VGA to SCART conversion circuit

If you�re a dab hand with a soldering iron and you live in Europe then you can cheaply make a circuit which will enable you to take the VGA output of the video card and plug it straight into the SCART socket on your TV. Theoretically this should give you the best output possible, although I strongly suspect the results seen will be dependent on your soldering skills. Instructions on how to make the circuit are here

Q1.7: How much disk space do I need?

The short answer is as much as you can afford. If, however, you�re not made of money, here are a few guidelines:

        • Video recorded via a PVR x50 typically comes in at 2GB/Hour
        • Standard Def DVB will typically be 1.2-2GB/Hour
        • High Def video will be somewhere between 3.5GB and 7GB/hour

Q1.8: I want a low power, quiet computer to use as a frontend. What are my choices??

Probably the best two choices are the Mac Mini and computers based around the mini-ITX form factor.

The Mac Mini is Apple�s small form factor computer. It has the benefit of looking extremely nice and being extremely small. While it does have a fan, this is generally regarded to be so quiet that it is not an issue. Power consumption is low (Tom's Hardware quotes 28W while playing DVDs) and since the operating system, OS X, is basically a UNIX derivative, it has been possible to port Mythfrontend to it.

The mini-ITX systems (often referred to as EPIA or VIA Eden boards) are another small factor computer, this time based on the x86 instruction set. They are not quite as small as the Mac Mini, but still pretty tiny and again they are very low power which is good for any computer that�s going to be left on all the time. They come with a range of processor speeds (between 600MHZ and 1.4GHZ) although the processing power is less than would be achieved with the equivalently clocked Intel chip. With the lower power chips it is possible for them to run fanless, although theses will probably struggle for tasks such as transcoding and commercial flagging.


2. Configuration

Q2.1: When using live TV, why is there a delay between the moment I change the channel and the time the channel actually changes?

When you are watching live tv in Myth, you are actually watching content which has first been written as a file to the hard disk. In doing so, the �live TV� that you are watching is actually TV that has been captured a few seconds beforehand. Whenever you change channel, the old file has to be removed and a new file created. The fact that his takes a couple of seconds is responsible for the gap you are seeing in between channel changes.

Although this doesn�t sound too good, it is necessary to create this file so that you can do cool stuff such as pausing and rewinding live TV. The �approved� method of using live TV is to use �browse mode� so that you can see what is on any given channel without having to change to that channel itself. The other main answer to this query is that once you have MythTV, you�ll rarely use live TV anyway on the grounds that all you favourite programs will be sitting on the hard drive ready to watch.

Of course if you do have any coding skills, there�s always the chance to have a look at the code to see if channel changing can be made any faster. You would certainly earn this FAQ writer�s gratitude if you did :)

Q2.2: When viewing video there is an annoying blue border round the side of the screen. How do I get rid of it?

You need a program called xvattr. When your X server starts, run the command:

xvattr -a XV_COLORKEY -v 0.

Q2.3: All my fonts look like they are the wrong sizes, how can I correct this?

The first thing to do is to make sure that the X Server is running at 100dpi as this is the resolution at which Myth is designed to operate. To find out what your resolution is use the command:

$ xpdyinfo | grep dots

If the response from this isn�t 100x100 dots per inch, you need to change your xorg.conf file to tell the X server the resolution to use.

Add a line:

Display Size x y

Under the "Monitor" section in your xorg.conf. Where x = (horizontal resolution)*0.254 and y = (vertical resolution)*0.254, both rounded up to the nearest integer.

If this doesn�t solve the problem then the chances are it�s a broken font package or something. Feel free to post the problem to the mailing list at this point, but make it clear you know you�re running at 100dpi or you�ll get lots of requests telling you to make the changes listed above.

Q2.4: I want to change the layout of my menus. What�s the best thing to do?

The data defining the main menu is kept in the files main_settings.xml and mainmenu.xml in /usr/share/mythtv/. It's probably best not to edit these files directly, as you might screw something up, so follow Jarod's advice and copy them into ~/.mythtv/ where you can edit them to your heart's content

Q2.5: I�m using the TV-Out on the PVR 350 and X is larger than the screen. Parts of the desktop and Myth interface are cut off around the edges

Currently the IVTV X driver only supports being run in full screen mode (720x 576 or 480). This will result in some of the picture being lost due to overscan. The way to fix this for MythTV (but not X in general) is to play about with the GUI X/Y size and displacement options under settings>playback settings (?)

3. Links To Useful Information

MythTV-Users mailing list archives MythTV project page MythTV Wiki Jarod�s guide for Fedora Knoppmyth Mini Myth Mythdora MythTV Docs Rage 3D Linux forums (TV out advice for those with ATi cards) IVTV mailing list archives PVR hardware database Category Faq