Difference between revisions of "Setup General"

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User Job #4 Command:
 
User Job #4 Command:
  
 
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===2. Capture Cars===
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--[[User:Mitchell2345|Mitchell]] 03:59, 19 March 2008 (UTC)In-progress
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===3. Video sources===
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--[[User:Mitchell2345|Mitchell]] 03:59, 19 March 2008 (UTC)In-progress
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===4. Input Connections===
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--[[User:Mitchell2345|Mitchell]] 03:59, 19 March 2008 (UTC)In-progress
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===5. Channel Editor===
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--[[User:Mitchell2345|Mitchell]] 03:59, 19 March 2008 (UTC)In-progress
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===6. Storage Groups===
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--[[User:Mitchell2345|Mitchell]] 03:59, 19 March 2008 (UTC)In-progress
  
 
====Starting mythbackend====
 
====Starting mythbackend====

Revision as of 03:59, 19 March 2008

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Backend

MythTV Detailed Backend Configuration v. 0.21. (Incomplete)


MythTV Backend

The backend process (mythbackend) is the portion of the system that handles the Video capture cards as well as Scheduling Recordings on those cards, Commercial Flagging, and transcoding. The backend process interacts with the Database and the hardware primarily.

As with the MythFrontend, there can be multiple backends. One backend process is designated as the master backend. This is usually the first backend installed on a system. This backend is responsible for coordinating the activities of the other backends known as slaves. This is especially true for scheduling as the master backend will determine the best distribution of programs across all available tuners. Each backend can have any number of tuners. Commercial Flagging can be distributed across different backends, thereby spreading the load of that process.

There is no requirement for direct user interaction with the backend. The backend can use local HardWare/File Storage or have it mounted from another system. If remotely mounted, network performance should be considered as there will be considerable traffic on the network as recordings are stored and retrieved by the backend process.

Communications Protocol

The backend and frontend communicate using their own Myth Protocol. The developer of Win Myth, a windows frontend to MythTV for playing recordings on Windows, has documented his workings on the procotol here. Work on defining the Myth Protocol is also being performed on this Wiki.

Backend Configuration

The MythTV Backend configuration has two main objectives

  • Tell MythTV what TV Capture/Tuner cards to use
  • Populate the Myth Database with information about channels and tuning information

There are additional items that can be configured, but without successfully achieving the above two steps you will not be able to get Live TV.

Running mythtv-setup

Configure the Myth backend like so

> /usr/bin/mythtv-setup

You will now see the GUI for MythTV to setup the backend server and in particular the channel tuning for our broadcast streams. You will need to set up:

  1. General — General Backend settings, most user can use the defaults
  2. Capture Cards — you will configure your capture cards/devices here
  3. Video Sources — create guide data.
  4. Input connections — connect the Capture Card name to the Video Source
  5. Channel Editor — scan for your channels here
  6. Storage Groups — Configure which folders your recordings will be saved.

General

Host Address Backend Setup
Setting Default Value Settings Page's Description Additional Comments
IP address for mythtv 127.0.0.1 Enter the IP address of this machine. Use an externally accessible address (ie, not 127.0.0.1) if you are going to be running a frontend or Slave Backend on a different machine than this one. MythTV is made up of two major components, the Backend and the Frontend. If you run the Backend and Frontend on the same machine then you can leave the setting at its default value of 127.0.0.1. This is referred to as the local loopback address. If you run multiple frontends, or run your frontend on a different machine then you will need to set this to a value the machines static IP address. This value will be determined by your TCPIP Network addressing scheme.
Port the server runs on 6543 Unless you’ve got a good reason to, don’t change this. As noted here you don't need to change this.
Port the server shows status on 6544 Port which the server will listen to for HTTP requests. Currently, it shows a little status information. You can connect to your MythTV box via a web browser at the machine's IP and this port. It shows some information on the status of the box but you should configure MythWeb for more advanced purposes.
Security Pin (Required) 0000 You will need to enter this PIN to authenticate to your backend. When using a remote frontend MythTV will auto discover your backend. For security you must entier this PIN into the frontend to gain access. This feature removes the need for the mysql.txt file in Prior verions (<=.20) Use four zero's (0) to disable this feature.
Master Server IP address 127.0.0.1 The IP address of the master backend server. All frontend and non-master backend machines will connect to this server. If you only have one backend, this should be the same IP address as above. If you're running only a frontend, set the IP address for your backend here.
Port the master server runs on 6543 Port which the server will listen to for HTTP requests. Currently, it shows a little status information. If you're running only a frontend, set the port for your backend here.
Locale Settings
Setting Default Value Settings Page's Description Additional Comments
TV format NTSC The standard to use for viewing TV. Other choices include: ASTC, PAL, SECAM, PAL-NC, PAL-M, PAL-N, NTSC-JP. Be sure to set to the proper format for your region.
VBI format None VBI stands for Vertical Blanking Interrupt. VBI is used to carry Teletext and Closed Captioning data. In TV broadcasting not all of the available lines in each frame of the picture are used. For example in CCIR systems (PAL and SECAM)25 lines per field (50 per frame) are specified for other uses. The remaining lines can be used for data broadcasting, and are typically used for closed caption or teletext. You may sometimes notice a squiggly black and white line or cube right at the top of the screen in a transmission; this is data being transmitted. In some countries, specific data broadcasting companies have exclusive rights on the use of the VBI lines. Options are None, PAL Teletext,
Channel frequency table us-cable Select the appropriate frequency table for your system. If you have an antenna, use a “-bcast” frequency. Other choices include: us-bcast, us-cable-hrc, japan-bcast, japan-cable, europe-west, europe-east, italy, newzealand, australia, ireland, france, china-bcast, southafrica, argentina, australia-optus.
Time offset for XMLTV listings None If your local timezone does not match the timezone returned by XMLTV, use this setting to have mythfilldatabase adjust the program start and end times. None disables this feature, Auto automatically detects your local timezone. Leave this alone if you're an American using the SchedulesDirect xml service.
Miscellaneous Settings
Setting Default Value Settings Page's Description Additional Comments
Master Backend Override Checked If enabled, the master backend will stream and delete files if it finds them in the video directory. Useful if you are using a central storage location, like a NFS share, and your slave backend isn’t running. This is the meat of the subject
Follow Symbolic links when deleting files Not checked This will cause Myth to follow symlinks when recordings and related files are deleted, instead of deleting the symlink and leaving the actual file. This is the meat of the subject
Delete Files Slowly Not checked Some filesystems use a lot of resource when deleting large recording files. This option makes Myth delete the file slowly on this backend to lessen the impact. Use this option if you expericane video studder while Myth deletes recordings in the backround.
HD Ringerbuffer size (kb) 4700 The HD device ringbuffer allows the backend to weather moments of stress. the larger the ringbuffer, the longer the moments of stress can be. However, setting this too large can cause swapping, which is detrimental. The default setting should be used in normal conditions. If you experience crashes when watching HD try increase this. You may need a stronger signal to eliminate the errors.
Miscellaneous Status Application blank External Application or script that outputs extra information for inclusion in the backend status page. See contrib/misc_status_info/README no comments.
Disable Firewire Reset Unchecked By default MythTV will reset the firewire bus when a firewire recorder stops responding to commands. But if this causes problems you can disable this here for Linux firewire recorders. no comments.
Shutdown/Wakeup Options
Setting Default Value Settings Page's Description Additional Comments
Startup command (empty) This command is executed right after starting the backend. As a parameter '$status' is replaced by either 'auto' if the machine was started or 'user' if a user switched it on. You may want to have post-startup tasks execute autonomously once the backend server has fully initialized. Use this parameter to specify a script that will get executed along with the backed server startup routines.
Block shutdown before client connected Checked If set, the automatic shutdown routine will be disabled until a client connects. If you have shutdown wakeup enabled, the backend will normally check to see if its busy before it shuts down. Of course if you have just turned your machine on manually then you don't want it to shut down before you have had a chance to start the frontend. Once the frontend has been started then the shutdown command will take effect as soon as the frontend closes down. This means that you only need to exit the frontend and the machine will go down. With MythTV 0.18 this created a problem with Mythweb, in that as soon as Mythweb connected to a backend which had no frontend process attached, it would think that a frontend connected then disconnected and consequently shut down. This has been fixed in 0.19.
Idle timeout (secs) 0 The amount of time the master backend idles before it shuts down all backends. Set to 0 to disable auto shutdown. MythTV can have multiple backends for the hardcore recording guy. Quite nice if you want to record lots of stuff at one time or if you are just a collector of all things broadcast. One of these backend machines will be designated as the Master Backend. This parameter controls how long the master backend idles, ie is not recording, transcoding or serving frontends before it decides to shut down all backends.
Max. wait for recording (min) 15 The amount of time the master backend waits for a recording. If it's idle but a recording starts within this time period, the backends won't shut down. You don't want the machine to think its idle only to find that by the time it has shut down it has to start again to record the next schedule. This parameter tells the system to wait a period of time just in case a recording is due.
Startup before rec. (secs) 120 The amount of time the master backend will be woken up before a recording starts. You often want to start a scheduled recording before it's actually scheduled according to the guide data. This is just in case it starts early or because you need to allow your machine time to boot in a wake up to record scenario. This parameter sets how much time you want to start the backend before the scheduled recording.
Wakeup time format hh:mm yyyy-MM-dd The format of the time string passed to the 'setWakeuptime Command' as $time. See QT::QDateTime.toString() for details. Set this parameter to be the same as that expected by the BIOS clock.
Command to set Wakeup Time Blank The command used to set the time (passed as $time) to wake up the master backend. This command needs to call an external script. Here is an example command '
sudo /usr/bin/mythsettime $time

where mythsettime is an external script that sets the wakeup command parameters in the bios. Here is the mythsettime script contents

 sudo echo $1 > /home/mythtv/myth.time
 sudo echo $1 > /proc/acpi/alarm
Server halt command sudo /sbin/halt -p The command used to halt the backends. This command needs to call an external script. Here is an example command '
 sudo /usr/sbin/mythshutdown

where mythshutdown is an external script that shuts the machine down. Here is the mythshutdown script contents

 sudo /sbin/halt -p
Pre Shutdown check-command Blank A command executed before the backend would shutdown. The return value determines if the backend can shutdown. 0 - yes, 1 - restart idling, 2 - reset the backend to wait for a frontend. Your machine may be doing other things such as Samba file sharing or streaming music that are not MythTV related. In this case you will want to have script here that checks stuff before it shuts down.

WakeOnLan settings

MasterBackend

Reconnect wait time (secs):

Count of reconnect tries:

Wake Command

Wake command for slaves:

Job Queue (Host-Specific)

Maximum simultaneous jobs on this backend:

Run Jobs only on original recording host

Job Queue Check frequency (in seconds)

CPU Usage

Allow Commercial Detection jobs

Allow User Job #1 jobs

Allow User Job #2 jobs

Allow User Job #3 jobs

Allow User Job #4 jobs


Job Queue (Global)

Run Jobs only on original recording backend.

Start Auto-commercial Flagging jobs when the recording starts.

Commercial Flagger command:

Transcoder command:

Run Transcode Jobs before Auto-Commericial Flagging

Save origional files after transcoding (globally)

Job Queue (Job Commands)

User Job #1 Description:

User Job #1 Command:

User Job #2 Description:

User Job #2 Command:

User Job #3 Description:

User Job #3 Command:

User Job #4 Description:

User Job #4 Command:

2. Capture Cars

--Mitchell 03:59, 19 March 2008 (UTC)In-progress

3. Video sources

--Mitchell 03:59, 19 March 2008 (UTC)In-progress

4. Input Connections

--Mitchell 03:59, 19 March 2008 (UTC)In-progress

5. Channel Editor

--Mitchell 03:59, 19 March 2008 (UTC)In-progress

6. Storage Groups

--Mitchell 03:59, 19 March 2008 (UTC)In-progress

Starting mythbackend

Once configuration is done you can test to see if the mythbackend process is running correctly by starting it in a Terminal window:

> /usr/bin/mythbackend

Watch out for any error messages.

You may also find it useful to read about Mythwelcome and ACPI Wakeup

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