Scantables

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What are scantables?

Scantables, or properly named Digital TV initial scanning tables are data used to speed up scanning for DTV frequencies. They are not a hard requirement per say, w_scan for example does not rely on them, it actually can create them. Most dvb applications however rely on them.

When trying to find the available TV channels for example, you would have to scan every single frequency with all possible settings. Since this is very time consuming, we supply initial data for certain regions so that the dvb applications in question only scan those known frequencies, saving a lot of time scanning. These tables however need to be kept up to date by users.

Creating DVB-T scan tables

There are a few methods to create a DVB-T scan file.

  • Use w_scan and have it scan the entire spectrum and it will output a table for you
  • Manually create/modify the file

It's best to look at the existing files on the format, http://git.linuxtv.org/dtv-scan-tables.git is a good starting point for that.

Submitting DVB-T scan tables

After creating or modifying a scan file, it's time to submit it for review and merge. The best method is to subscribe and send it to the linux-media@vger.kernel.org mailing list. Ideally a To/CC to 'oliver <at> schinagl <period> nl'. The better the quality of your patch (e.g. it can be merged using git am without problem) the quicker it will lend upstream.

If using e-mail is troublesome, it is possible to fork and submit a pull request via https://github/oliv3r/dtv-scan-tables although that method is not prefers as it bypasses the mailing list. Patches submitted this way will be sent to the Mailing list for review before being pushed to git.linuxtv.org.