[mythtv] Re: [mythtv-commits] Re: Ticket #437: EIT crawl transport scan

[Stuart Auchterlonie]

On Sun, Oct 09, 2005 at 01:20:27PM -0400, Daniel Kristjansson wrote:
> On Sun, 2005-10-09 at 18:02 +0100, Stuart Auchterlonie wrote:
> > On Sun, Oct 09, 2005 at 04:25:28PM -0000, MythTV wrote:
> > > #437: EIT crawl transport scan
> > >  I did not add the part where it disables channel scanning
> > >  entirely if you are using dvb-on-demand. We should instead
> > >  just sleep for a while between scans. I also added a check
> > >  for "useonairguide = 1" to the channel query for the scan.
> > Thought that was what you wanted? (dvb_on_demand)
> > Doesn't disable it entirely, just doesn't add those channels
> > to the channel list.
> dvb-on-demand is a tuner setting, so it wouldn't scan any channels
> on that tuner.. We still want to scan dvb-on-demand cards, we just
> don't want to scan them continuously.

Well without dvb_on_demand = 0 then those channels will be scanned
continuously.

The intention was to grab a list of channels that are not on
demand only tuners and walk through them.

When someone watches a channel on an on demand tuner then they
will get eit data.

Remember this is only the active scan case here....


> 
> > As for useonairguide, that is already handled at the event
> > insertion level. 
> Yes, but why scan channels where there is no good EIT data?
> 

We don't want to scan channels without good EIT data.

It comes down to the fact that useonairguide does not actually
mean useonairguide, it actually means there is EIT data present 
on this channel. 

During event insertion however, it is used to determine if an
event should be inserted into the DB.


In the situation where
1) EIT data is transmitted on a specific channel.
2) The channel (to be watched) doesn't carry EIT data

With the current logic, channel (#2) would not have
useonairguide set when we scanned for channels, since it 
doesn't carry eit data. 

But when we tune to channel #1, we will get EIT data for lots
of channels, but since channel #2 doesn't have useonairguide
set the event info will be dumped.

To do this properly, we really should have another field
eit_present (which is set like useonairguide is currently
set when the channels are scanned) and initially set
useonairguide to true. Then if people don't want to use the
onairguide for a channel they can turn it off and get it
from another more reliable source.

Does this make sense?

This is a valid scenario (mainly under dvb-s)


Stuart