Improved discrimination and channel-name maintenance in MPEG & ATSC channel scans

[Paul Milazzo <pgm0203@…>]

The following patch makes several small improvements to the channel-scanning process for ATSC and MPEG-only (no SI data) scans:

• Allow callsign and service name to differ.
• For transports without inband SI data (e.g. many US cable-TV providers):
  • Avoid adding channels for which at least one of the following is true:
    1. We cannot find the PMT.
    2. We want FTA channels only, but the channel appears to be encrypted.
    3. The video stream contains the still-picture flag (e.g. it's a Music Choice^(R) channel); Myth currently does not play these streams correctly.
  • Don't overwrite known callsign and service name when updating an existing channel. In the absense of SI data this information must have been entered by hand and should not be overwritten by subsequent scans.
• For transports with ATSC PSIP data:
  • If the VCT entry for a given channel includes an Extended Channel Name Descriptor, use the Extended Channel Name as the service name rather than duplicating the callsign. Otherwise use the Short Channel Name (which is used as the callsign) as was done before.

[Paul Milazzo <pgm0203@…>]

Oops; forgot to attach the patch file.

[danielk]

(In [7290]) Closes #361.

Contribution from Paul Milazzo.

This grabs the extended name for ATSC channels when it available, and changes the "Cable" scan so that it checks for encryption and "Still Picture" services.

See the ticket for more details.