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19. Miscellaneous.

19.1 I'd like to watch the files without using MythTV / I'd like to convert the files to some other format.

Matthew Zimmerman has created a patch for MPlayer / Mencoder http://www.mplayerhq.hu that allows you view the files created by MythTV. MythTV doesn't use standard Nupplevideo files, which is why you MPlayer complains if you try to view them.

Download the patch to MPlayer from Matt's website. http://dijkstra.csh.rit.edu:8088/~mdz/mythtv/.

$ wget http://dijkstra.csh.rit.edu:8088/~mdz/mythtv/mplayer-0.90pre10+mythtv.patch

Download the source to MPlayer and patch:

$ wget http://ftp.lug.udel.edu/MPlayer/releases/MPlayer-0.90rc1.tar.bz2
$ tar -xjf MPlayer-0.90rc1.tar.bz2
$ cp mplayer-0.90pre10+mythtv.patch MPlayer-0.90rc1
$ cd MPlayer-0.90rc1
$ patch -p1 < mplayer-0.90pre10+mythtv.patch

At this point, you can read the MPlayer documentation and start the compile process.

19.2 I'd like to use some other window manager.

MythTV is not dependent on any particular window manager. If you wish to run a lightweight window manager, the configfiles/ directory has an example of a .twmrc file you may use.

19.3 I'd like MythTV to automatically startup.

Here's an example submitted to the mythtv-dev list by Pat Pflaum mailto:pat@netburp.com using fvwm:

$ cat > .xinitrc
fvwm &
mythfrontend
^D
$ cat > .fvwmrc
Style "myth*"      NoTitle, NoHandles, Sticky, WindowListSkip, BorderWidth 0
^D
$

19.4 What capture resolution should I use? How does video work?

While MythTV allows you to set various GUI and capture resolutions, not all combinations make sense.

First, analog video signals have a defined vertical resolution. In NTSC, the video standard specifies that there are 525 vertical scan lines. Once the "extra" lines are removed (they're used to synchronize the video signal, and encode closed captioning data), you have 480 vertical lines.

In PAL, there are 625 "raw" lines of resolution, with a net of 576 vertical lines.

Horizontally, the maximum you can expect from a Bt8X8 chip is 720.

With this in mind, there are certain commonly accepted values for resolution. While other values may be accepted, they will cause scan lines to be repeated or dropped.

From "best" to "worst", in NTSC:

As you can see, the lower quality values are half of the better ones. 720x240 is possible, but isn't a good tradeoff relative to the number of vertical lines lost. In a PAL country, the you would use values like 720x576 or x288.

The higher resolutions will be more CPU intensive. If the CPU is overtaxed, frames will be dropped causing uneven motion. You will likely see the best results at resolutions which average at least 10% CPU idle time. You can use system tools such as top or sar to check the CPU % idle while recording. If the CPU average usage is consistently exceeding 90%, frames will need to be dropped during peak times when more than 100% of the available CPU would be needed to process all of the frames.

If you'd like to read more on this, go to the vcdhelp website at http://www.vcdhelp.com/forum/userguides/94382.php.

19.5 MythTV GUI and X Display Sizes.

MythTV is designed to be run as dedicated full screen TV application but can also be run as a desktop application on a computer monitor. Here are a few consideration for configuring sizes to best suit you needs.

There are three sizes that are important for matching the MythTV GUI and full screen TV playback to fit the screen:

The MythTV GUI uses its GUI dimensions regardless of the other two and is anchored to the upper left corner of the X Desktop.

The MythTV full screen mode uses the X display size dimensions regardless of the other two and is anchored to the upper left corner of the X display.

X Dimensions

For output to a Television, common resolutions are 640x480, 800x600, and some rare devices support 1024x768. Generally, higher resolutions are better. However, you may find that you prefer the picture quality at one of the lower resolutions. Everything in MythTV is scalable and should 'fit' regardless of the resolution you choose.

Edit your X configuration file, usually "XF86Config-4", so that the the resolution you want to use is listed first in the lists under "Screen". If this resolution is higher than the resolutions supported by your output device, you will see a 'panning' effect where moving the mouse to the edge will scroll around a desktop area which is larger than the display size. If this happens, edit your X configuration file to match the display size then restart X.

MythTV Dimensions

In 0.8, from "mythfrontend" go to Setup->Appearance. The default for the height and width on 0.8 is "0" - this will cause MythTV to automatically size itself to full screen. To ensure that your new dimension settings take effect, exit and restart MythTV.

NOTE: When the GUI is full screen, you may need to set your window manager to 'Click to Focus' for windows to stack properly.

The fonts for the GUI and OSD will scale to whatever sizes you use. Most font sizes can be changed in setup selections. Make sure to use fonts large enough to be read on a TV screen from a distance.

The full screen TV size is based on the X display size. For Xinerama, you can specify a screen in Setup->General. The picture will be stretched to fit the entire screen regardless of the capture resolutions used.

Overscan Dimensions

Because picture edges can be ragged and screen edges aren't straight, Television is designed to project an image larger than the physical screen. This is called "overscan". Underscan is fitting the entire image inside the screen. This is useful for computer monitors so that toolbars and scrollbars at the edges can be seen.

For best results, match the X display area as close as possible to the edges of the physical screen. This can only be adjusted by your tv-out device or by the settings for the television set. Many sets have these adjustments in a 'service mode'.

MythTV has settings for "Overscan" in Setup->Playback. These can not, and do not, cause the image to display beyond the edge of the X display area. The purpose of these settings are to cut off rough edges and to expand the image so that objects will appear to be the same size as a normal overscanned TV picture.

MythTV on the Desktop

When using MythTV on a high resolution desktop monitor, set the MythTV GUI dimensions to something much smaller than your X display resolution but still large enough to read the fonts. The GUI screens will always be in the upper left hand corner. However, your window manager may be able to minimize these (ALT-F4 in KDE for example).

The TV picture will start in full screen mode. Press "f" to put the picture in a window that can be moved and resized. By default, the picture uses the recording resolution for its dimensions. If you check the box "Fixed Aspect Ratio" in Setup->Playback, the windowed picture will always be resized to normal 4:3 shape.

19.6 I'd like to save or restore my database

See the mysqldump manpage for more information.

$ mysqldump -u mythtv --password=mythtv mythconverg > mythtv_backup.sql

To restore:

$ mysql -u mythtv --password=mythtv mythconverg < mythtv_backup.sql

19.7 I'd like to delete the mysql database.

NOTE: Performing this step will remove the entire database. You will lose all of your settings and will need to re-run the mc.sql script to setup the database structure before running the setup program.

$ mysql -u root
mysql> drop database mythconverg;
mysql> quit


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