View source for Repairing the Seektable

It is possible that the [[Recordedseek_table|seektable]] can become corrupted for one or more recordings, which can result in:
* Being unable to skip forward and backward correctly, and
* Recordings reporting the incorrect length.

[[mythcommflag]] and [[mythtranscode]] are two tools that can be used to rebuild the seektable.

[[Image:Important.png]] '''Note:''' After rebuilding the seektable, any cutlist which has created for a recording will no longer be properly synced and should be recreated.

= Repairing the Seektable=
== Preparation==
First, run the <code>optimize_mythdb.pl</code> script to ensure that the MySQL database is in good order.  This script should be run by a user with a valid <tt>~/.mythtv/config.xml</tt>, which provides the required the database connection information.  Since <tt>~/.mythtv/config.xml</tt> is also used by mythfrontend and will be created by  mythfrontend if it doesn't already exist, running <code>optimize_mythdb.pl</code> as a user who has previously run mythfrontend is recommended.

On an Ubuntu machine, for example, running <tt>optimize_mythdb.pl</tt> is as simple as running the following command:
 /usr/share/doc/mythtv-backend/contrib/maintenance/optimize_mythdb.pl

This will iterate through each of the tables in the mythconverg database, 'optimizing' each one.  Once the <code>optimize_mythdb.pl</code> script has returned successfully, it is time to move on.

== Using mythcommflag==
For each recording with corrupted seektable in need of repair, run the following command:
 mythcommflag --file <filepath> --rebuild

where <code><filepath></code> is the path to a recording that exists in the Myth TV database.  There are other options that can be used to specify the input filename(s), refer to the [[mythcommflag]] page for further details.

{{Note box|mythcommflag should ''always'' be used for files that are recording in or transcoded to NUV}}


== Automation of mythcommflag repair function==

If lost seektables are a recurring occurrence for your setup and you have users who are less happy with tracking down a file name and running a command line repair tool against it, the following tip may be useful.

Define a [[User Jobs]] with a descriptive name e.g. "fixseek", this should have the command:
 mythcommflag --file %FILE% --rebuild

The name you have selected e.g. "fixseek" will now appear as a new option below "Job Options" on the "Recording Options" menu.
Progress on the repair can be seen within the "System Status/Job Queue" menu.

== Using mythtranscode==
If problems are encountered rebuilding a seektable for MPEG-2 recording files with mythcommflag, try using mythtranscode as follows:
 mythtranscode --mpeg2 --buildindex --allkeys --showprogress --infile <filepath>

where <code><filepath></code> is the path to a recording that exists in the Myth TV database.  There are other options that can be used to specify the input filename, refer to the [[mythtranscode]] page for further details.

= Possible Causes of a Corrupt Seektable=
* Editing or converting a recording outside of the MythTV Frontend GUI (such as a custom post-processing script).
* Excessive disk IO during recording could prevent invalid SQL updates to the [[recordedseek table]] (I think).
* Crashed MySQL tables.
* Losing the network between slave backends and the MySQL database server during recordings.
* Alternatively, files imported into the MythTV recordings library may need to have their seektables built, especially if they are to be edited.

[[Category:HOWTO]]