11. Using MythTV.

NOTE to Red Hat/Fedora 4 users: Red Hat Linux and Fedora Core ship with Gnome as the default desktop environment. However, Gnome seems to have issues with window focus and window switching which sometimes cause mythfrontend to obscure the video. KDE does not seem to have any such issues. Therefore you will need to switch to KDE by selecting RedHatMenu>Extras>System Settings>Desktop Switching Tool and choose "KDE". NOTE to Fedora Core 5 and 6 users: Fedora 5 and 6 no longer have this tool in the Menu. Use "switchdesk KDE" from a command line. Read "man switchdesk" for further information about changing to other desktop environments.

11.1 Keyboard commands

The keys.txt file describes what the various keyboard commands are. If you have loaded mythweb, you may change the default keys to your liking.

mythfrontend

Watching TV or a recording

Watching TV only

LiveTV Browse Mode

Playback Recording Zoom Mode

If you have two or more tuner cards

Watching a recording only

EPG

Setting Program or Channel Recording Priorities

Viewing Scheduled Recordings/Resolving Conflicts

Viewing Search Listings

Recording Profiles Setup Screen

Recording Groups

In the Watch Recordings screen, Recording Groups allow you to separate programs into user-defined categories, such as "Kids", "Alice", "Bob", etc. This can be used to reduce clutter, or to segregate content if you use the PIN function.

Watch Recordings Screen

Remote Controls

If you are using MythTV with just a remote control then it is suggested that you map the remote control keys as described below. Your remote control may not have the same set of keys as those named below, the names are only a suggestion that roughly correspond to the function.

If you are adding new key bindings to the program then consideration of this suggested list will help users with remote controls.

This list assumes a minimal remote control that only has 20 keys, nearly all features can be used with this configuration. If you have more keys then you can access all of the features. With only 16 keys most features are usable.

11.2 Using themes with MythTV

MythTV is "themeable", meaning that the visual appearance of the program can be modified by the user without re-compiling or altering the program functionality. Download the MythThemes tarball from the website and untar it:

$ tar -xjf myththemes-0.21.tar.bz2
$ cd ~/myththemes-0.21
$ qmake myththemes.pro
$ su -
# make install
# exit
$

The theme will now be available in the mythfrontend Appearance section.

11.3 Adding DishTV information to the database

A script for adding Pay Per View information into the MythTV database for DishTV subscribers is available at http://www.mythppv.com/.

11.4 Adding support for an external tuner

MythTV supports changing the channel on an external tuner. If you have an external tuner, such as a DirecTV or digital cable set top box, you should add /usr/local/bin/changechannel to your Input Connections in the mythbackend configuration GUI.

However, there is not changechannel program per-se, because this is going to be dependent on what sort of external tuner you have. Look in the contrib/channel_changers directory for a number of programs and scripts which may be used to change channels. Once you find one which works, copy it to /usr/local/bin/changechannel.

Feel free to browse some of what sort of hardware is available at http://store.snapstream.com/accessories.html, or if you wish to assemble your own, rather than purchase, the following may be helpful: http://www.dtvcontrol.com/ for cable pinouts.

11.5 Using Shutdown/Wakeup

What does the MythTV Shutdown/Wakeup function do? The scheduler on the Master backend (MBE) keeps track of the idle status of the entire MythTV system, including the Slave backends (SBE). If it considers the system to be idle, and thus ready to shutdown, it sets the wakeuptime to the time of the next recording and then proceeds to shut down all Slave backends and then itself. Once it is time to begin recording, the Master backend and the Slave Backends are automatically woken up. This system allows MythTV to record like a normal VCR, thereby conserving power when not in active use.

In order to use the Shutdown/Wakeup function there must be some method of waking up the Master backend. There are any number of solutions, but we will discuss in detail two possibilities:

• Use another server that runs 24/7 and have it send a WakeOnLAN (WOL) packet to wake the Master backend. This assumes that you have the WOL tools installed, and that your Master backend motherboard supports WOL.
• Use your motherboard's BIOS wakeup capability. You'll need a motherboard that supports BIOS wakeup, and some tools. Two that work are: http://sourceforge.net/projects/nvram-wakeup and http://www.malloc.de/tools/wakeup_clock.html

A deeper look into the operation

The scheduler keeps track of the idle status of the MythTV system. To determine whether or not the MythTV system is idle, the following conditions must be met for a period of time defined in the "Idle timeout (secs)" parameter.

• no client is connected to the server
• no recording (neither LiveTV nor a regular recording) is currently taking place
• no recording starts within a definable amount of time ("Max. wait for recording (min)")
• the "pre Shutdown check-command" returns 0

If we get to this idle state the Master backend will set the wakeuptime using the "Set wakeuptime command", which is the same for WOL and BIOS wakeup. The Master backend will then shut down the Slave backends and itself using the "Server halt command".

One caveat is that the scheduler tries to guess if the Master backend was started by a wakeup call or by the user. If it thinks it was woken up by a user, it blocks shutdown until a client connects to the Master backend, after which it will behave as described above. To disable this feature, unset "Block shutdown before client connected" in the mythfrontend Setup->Setup->General screen.

Once it is time to startup the system, the Master backend is woken up first and will wakeup the Slave backends using the "Wake command for slaves". At this time, there is no support for starting only the required Slave backend, so all Slave backends will startup.

Setting up the MythTV side of this extension.

There are a number of options that are used to control the Shutdown / Wakeup feature.

Shutdown/Wakeup Options:

• "Idle timeout (secs)" is the time the server waits while idle until a shutdown occurs.
• "Max. wait for recording (min)" is the time the Master backend waits for a recording without shutting down. For example, this would be used to prevent a 10 minute system shutdown if a recording is set to start 15 minutes from now.
• "Startup before rec. (secs)" Sets how long before a programmed recording the MythTV system will be woken up. This should be roughly be the time your systems need to bootup, and if you have Slave backends, you'll need to ensure this value is long enough for all your machines to perform their bootup cycle.
• "Wakeup time format" is the format of the wakeup time that is given in the "Set wakeuptime command" as a parameter "$time". You need to set this according to your wakeup mechanism. If you need seconds since the epoch (1970-01-01) set the "Wakeup time format" to "time_t".
• "Set wakeuptime command" is the command executed to set the new wakeuptime.
• "Server Halt Command" is the command executed to shutdown the Master backend and the Slave backends.
• "pre Shutdown check-command" is used to give a "Go/NO-GO" decision from a non-MythTV source. This command is executed immediately before the shutdown would occur. The return value is use to make the following choices:
  • If it returns a "0" the shutdown will occur as scheduled.
  • If it returns a "1" the "idle timeout" will be reset and the system waits again for the timeout.
  • If it returns a "2" the entire shutdown sequence is reset. This means that a new client connect is needed before a shutdown occurs, unless you have the "Wait for client connect" setting disabled, in which case this is the same as returning "1". An example of a use for this return value is to prevent the shutdown if a user is currently logged in, or if a specific program (i.e. transcode, automatic updates, etc.) is currently running. If you don't need it, leave the field blank.

The "WakeOnLan settings": These settings have nothing to do with using BIOS or WOL wakeup, they are the same for both.

• "Master backend" This setting defines timings for the frontends to wakeup the Master backend using WOL. Useful if your frontend can emit a WOL packet so you don't need to physically go to the Master backend if you're trying to watch TV.
• "Reconnect wait time (secs)" is the time the frontend waits after executing the "Wake command" before attempting to retry the connection. This should be roughly the amount of time your Master backend needs for bootup. Set to "0" to disable. The frontends will retry to connect for "Count of reconnect tries" times before giving up.
• "Wake command for slaves" is the one command executed to wake your Slave backends. This should be a script that contains the calls to wakeup all Slave backend systems.

Using WOL to wake your Master backend.

To use WOL to wake your Master backend you will need a WOL capable Master backend, a machine that runs 24/7 which can execute an at-job and nc (netcat) on the Master backend. I use some little bash scripts to make my DSL router wakeup my mythbox if required.

Replace $SERVER and $PORT with your own settings! On my Master backend I have a script that gets called as 'setwakeuptime command' which looks like the following:

#! /bin/sh
echo $@ | nc $SERVER $PORT

If you use inetd:

In /etc/inetd.conf add:

mythwake stream tcp nowait mythtv /usr/sbin/tcpd /usr/local/bin/mythwake

service mythwake
  {    
        socket_type     = stream
        wait            = no
        user            = mythtv        
        protocol        = tcp
        id              = mythwake
        server          = /usr/local/bin/mythwake
  }

mythwake        $PORT/tcp

Finally, /usr/local/bin/mythwake looks like:

#! /bin/bash
#this should be a command to wake your server
WAKECMD="#!/bin/sh\n /usr/local/bin/wakeMBE"
#first we need to delete all wake jobs in queue
for JOB in atq | cut -f 1 ; do
    atrm $JOB;
done
#now we read the date from 'nc'
read date;
#now set the atjob
echo -e "$WAKECMD" | at $date ;

Using BIOS wakeup to wake your Master backend.

Since I don't use this, I cannot say much about this. If your motherboard supports any wakeup tool you have to call that tool as "Set wakeuptime command" with the "Wakeup time format" suitable for that tool.

Wakeup the MySQL server using WOL

If your MySQL server and your Master backend are not on the same machine, you can have the Master backend wake your MySQL server using WOL. You will find the settings for this in the second page of the mythtv-setup program, or at the end of mysql.txt. The meanings are the same as discussed in "The WakeOnLan settings" above.

Tips/Tricks:

If, for example, one of the Slave backends is also your desktop computer, you could simply use a little script as 'server halt command' which first calls /sbin/shutdown -t TIMEOUT where TIMEOUT is a value sufficient for you to react. You could then popup a window using *dialog, asking for permission to shutdown. If you cancel the shutdown, simply call /sbin/shutdown -c.

If you get "nvram-wakeup: /dev/rtc: Device or resource busy" your set-wakeuptime-script should stop the program that uses /dev/rtc before setting the wakeuptime.

11.6 Controlling the mythfrontend via telnet

To use this feature you must first enable it in Settings>General>General

The network control listens on port 6546, as demonstrated below:

$ telnet basement 6546
Connected to basement.
Escape character is '^]'.
MythFrontend Network Control
Type 'help' for usage information
---------------------------------
# help
Valid Commands:
---------------
jump               - Jump to a specified location in Myth
key                - Send a keypress to the program
play               - Playback related commands
query              - Queries
exit               - Exit Network Control

Type 'help COMMANDNAME' for help on any specific command.

# help jump
Usage: jump JUMPPOINT

Where JUMPPOINT is one of the following:
channelpriorities    - Channel Recording Priorities
channelrecpriority   - Channel Recording Priorities
deletebox            - TV Recording Deletion
deleterecordings     - TV Recording Deletion
guidegrid            - Program Guide
livetv               - Live TV
livetvinguide        - Live TV In Guide
mainmenu             - Main Menu
...snip...
# exit
$

Please note that this feature only allows one connection at a time, so any new connections will automatically terminate prior ones.